add new api to check for rotation/flip changes (#24)

* add new api to check for rotation/flip changes

Signed-off-by: Glease <4586901+Glease@users.noreply.github.com>

* add a bit javadoc

Signed-off-by: Glease <4586901+Glease@users.noreply.github.com>

---------

Signed-off-by: Glease <4586901+Glease@users.noreply.github.com>

.git-blame-ignore-revs

@@ -0,0 +1,2 @@
+# Ignore spotlessApply reformat
+464e44de8541a46833f50c3bd363d50e1677a685

.gitattributes

@@ -1,22 +1,44 @@
-# Auto detect text files and perform LF normalization
-* text=auto
+* text eol=lf
 
-# Custom for Visual Studio
-*.cs     diff=csharp
-*.sln    merge=union
-*.csproj merge=union
-*.vbproj merge=union
-*.fsproj merge=union
-*.dbproj merge=union
+*.[jJ][aA][rR]          binary
 
-# Standard to msysgit
-*.doc	 diff=astextplain
-*.DOC	 diff=astextplain
-*.docx diff=astextplain
-*.DOCX diff=astextplain
-*.dot  diff=astextplain
-*.DOT  diff=astextplain
-*.pdf  diff=astextplain
-*.PDF	 diff=astextplain
-*.rtf	 diff=astextplain
-*.RTF	 diff=astextplain
+*.[pP][nN][gG]          binary
+*.[jJ][pP][gG]          binary
+*.[jJ][pP][eE][gG]      binary
+*.[gG][iI][fF]          binary
+*.[tT][iI][fF]          binary
+*.[tT][iI][fF][fF]      binary
+*.[iI][cC][oO]          binary
+*.[sS][vV][gG]          text
+*.[eE][pP][sS]          binary
+*.[xX][cC][fF]          binary
+
+*.[kK][aA][rR]          binary
+*.[mM]4[aA]             binary
+*.[mM][iI][dD]          binary
+*.[mM][iI][dD][iI]      binary
+*.[mM][pP]3             binary
+*.[oO][gG][gG]          binary
+*.[rR][aA]              binary
+
+*.7[zZ]                 binary
+*.[gG][zZ]              binary
+*.[tT][aA][rR]          binary
+*.[tT][gG][zZ]          binary
+*.[zZ][iI][pP]          binary
+
+*.[tT][cC][nN]          binary
+*.[sS][oO]              binary
+*.[dD][lL][lL]          binary
+*.[dD][yY][lL][iI][bB]  binary
+*.[pP][sS][dD]          binary
+*.[tT][tT][fF]          binary
+*.[oO][tT][fF]          binary
+
+*.[pP][aA][tT][cC][hH]  -text
+
+*.[bB][aA][tT]          text eol=crlf
+*.[cC][mM][dD]          text eol=crlf
+*.[pP][sS]1             text eol=crlf
+
+*[aA][uU][tT][oO][gG][eE][nN][eE][rR][aA][tT][eE][dD]* binary

.github/workflows/pages.yml

@@ -1,47 +0,0 @@
-# Simple workflow for deploying static content to GitHub Pages
-name: Deploy static content to Pages
-
-on:
-  # Runs on pushes targeting the default branch
-  push:
-    branches: ["gh-pages"]
-
-  # Allows you to run this workflow manually from the Actions tab
-  workflow_dispatch:
-
-# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
-permissions:
-  contents: read
-  pages: write
-  id-token: write
-
-# Allow one concurrent deployment
-concurrency:
-  group: "pages"
-  cancel-in-progress: true
-
-jobs:
-  # Single deploy job since we're just deploying
-  deploy:
-    environment:
-      name: github-pages
-      url: ${{ steps.deployment.outputs.page_url }}
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v3
-      - name: Setup Pages
-        uses: actions/configure-pages@v2
-      - name: Generate Index
-        shell: bash
-        run: |
-          find . -name javadoc -type d -print > index.txt
-          echo feature/doc >> index.txt
-      - name: Upload artifact
-        uses: actions/upload-pages-artifact@v1
-        with:
-          # Upload entire repository
-          path: '.'
-      - name: Deploy to GitHub Pages
-        id: deployment
-        uses: actions/deploy-pages@v1

.github/workflows/publish-javadoc.yaml

@@ -20,13 +20,16 @@ jobs:
     outputs:
       result_hash: ${{ steps.deploy.outputs.hash }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
         with:
           fetch-depth: 0
 
-      - uses: actions/setup-java@v2
+      - uses: actions/setup-java@v3
         with:
-          java-version: 8
+          java-version: |
+            8
+            11
+            17
           distribution: 'temurin'
           cache: gradle
 
@@ -51,7 +54,7 @@ jobs:
             echo Nothing to deploy
             exit 0
           fi
-          find . -name javadoc -type d -print | sed 's#^\./\(.*\)/javadoc$#\1#' > index.txt
+          find . -name javadoc -type d -print | sed 's#^\./\(.*\)/javadoc$#\1#' | sort --version-sort --reverse > index.txt
           git add index.txt
           git config user.name "${GITHUB_ACTOR}"
           git config user.email "${GITHUB_ACTOR}@users.noreply.github.com"

LICENSE.txt

@@ -0,0 +1,165 @@
+                   GNU LESSER GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+
+  This version of the GNU Lesser General Public License incorporates
+the terms and conditions of version 3 of the GNU General Public
+License, supplemented by the additional permissions listed below.
+
+  0. Additional Definitions.
+
+  As used herein, "this License" refers to version 3 of the GNU Lesser
+General Public License, and the "GNU GPL" refers to version 3 of the GNU
+General Public License.
+
+  "The Library" refers to a covered work governed by this License,
+other than an Application or a Combined Work as defined below.
+
+  An "Application" is any work that makes use of an interface provided
+by the Library, but which is not otherwise based on the Library.
+Defining a subclass of a class defined by the Library is deemed a mode
+of using an interface provided by the Library.
+
+  A "Combined Work" is a work produced by combining or linking an
+Application with the Library.  The particular version of the Library
+with which the Combined Work was made is also called the "Linked
+Version".
+
+  The "Minimal Corresponding Source" for a Combined Work means the
+Corresponding Source for the Combined Work, excluding any source code
+for portions of the Combined Work that, considered in isolation, are
+based on the Application, and not on the Linked Version.
+
+  The "Corresponding Application Code" for a Combined Work means the
+object code and/or source code for the Application, including any data
+and utility programs needed for reproducing the Combined Work from the
+Application, but excluding the System Libraries of the Combined Work.
+
+  1. Exception to Section 3 of the GNU GPL.
+
+  You may convey a covered work under sections 3 and 4 of this License
+without being bound by section 3 of the GNU GPL.
+
+  2. Conveying Modified Versions.
+
+  If you modify a copy of the Library, and, in your modifications, a
+facility refers to a function or data to be supplied by an Application
+that uses the facility (other than as an argument passed when the
+facility is invoked), then you may convey a copy of the modified
+version:
+
+   a) under this License, provided that you make a good faith effort to
+   ensure that, in the event an Application does not supply the
+   function or data, the facility still operates, and performs
+   whatever part of its purpose remains meaningful, or
+
+   b) under the GNU GPL, with none of the additional permissions of
+   this License applicable to that copy.
+
+  3. Object Code Incorporating Material from Library Header Files.
+
+  The object code form of an Application may incorporate material from
+a header file that is part of the Library.  You may convey such object
+code under terms of your choice, provided that, if the incorporated
+material is not limited to numerical parameters, data structure
+layouts and accessors, or small macros, inline functions and templates
+(ten or fewer lines in length), you do both of the following:
+
+   a) Give prominent notice with each copy of the object code that the
+   Library is used in it and that the Library and its use are
+   covered by this License.
+
+   b) Accompany the object code with a copy of the GNU GPL and this license
+   document.
+
+  4. Combined Works.
+
+  You may convey a Combined Work under terms of your choice that,
+taken together, effectively do not restrict modification of the
+portions of the Library contained in the Combined Work and reverse
+engineering for debugging such modifications, if you also do each of
+the following:
+
+   a) Give prominent notice with each copy of the Combined Work that
+   the Library is used in it and that the Library and its use are
+   covered by this License.
+
+   b) Accompany the Combined Work with a copy of the GNU GPL and this license
+   document.
+
+   c) For a Combined Work that displays copyright notices during
+   execution, include the copyright notice for the Library among
+   these notices, as well as a reference directing the user to the
+   copies of the GNU GPL and this license document.
+
+   d) Do one of the following:
+
+       0) Convey the Minimal Corresponding Source under the terms of this
+       License, and the Corresponding Application Code in a form
+       suitable for, and under terms that permit, the user to
+       recombine or relink the Application with a modified version of
+       the Linked Version to produce a modified Combined Work, in the
+       manner specified by section 6 of the GNU GPL for conveying
+       Corresponding Source.
+
+       1) Use a suitable shared library mechanism for linking with the
+       Library.  A suitable mechanism is one that (a) uses at run time
+       a copy of the Library already present on the user's computer
+       system, and (b) will operate properly with a modified version
+       of the Library that is interface-compatible with the Linked
+       Version.
+
+   e) Provide Installation Information, but only if you would otherwise
+   be required to provide such information under section 6 of the
+   GNU GPL, and only to the extent that such information is
+   necessary to install and execute a modified version of the
+   Combined Work produced by recombining or relinking the
+   Application with a modified version of the Linked Version. (If
+   you use option 4d0, the Installation Information must accompany
+   the Minimal Corresponding Source and Corresponding Application
+   Code. If you use option 4d1, you must provide the Installation
+   Information in the manner specified by section 6 of the GNU GPL
+   for conveying Corresponding Source.)
+
+  5. Combined Libraries.
+
+  You may place library facilities that are a work based on the
+Library side by side in a single library together with other library
+facilities that are not Applications and are not covered by this
+License, and convey such a combined library under terms of your
+choice, if you do both of the following:
+
+   a) Accompany the combined library with a copy of the same work based
+   on the Library, uncombined with any other library facilities,
+   conveyed under the terms of this License.
+
+   b) Give prominent notice with the combined library that part of it
+   is a work based on the Library, and explaining where to find the
+   accompanying uncombined form of the same work.
+
+  6. Revised Versions of the GNU Lesser General Public License.
+
+  The Free Software Foundation may publish revised and/or new versions
+of the GNU Lesser General Public License from time to time. Such new
+versions will be similar in spirit to the present version, but may
+differ in detail to address new problems or concerns.
+
+  Each version is given a distinguishing version number. If the
+Library as you received it specifies that a certain numbered version
+of the GNU Lesser General Public License "or any later version"
+applies to it, you have the option of following the terms and
+conditions either of that published version or of any later version
+published by the Free Software Foundation. If the Library as you
+received it does not specify a version number of the GNU Lesser
+General Public License, you may choose any version of the GNU Lesser
+General Public License ever published by the Free Software Foundation.
+
+  If the Library as you received it specifies that a proxy can decide
+whether future versions of the GNU Lesser General Public License shall
+apply, that proxy's public statement of acceptance of any version is
+permanent authorization for you to choose that version for the
+Library.

README.md

@@ -32,3 +32,5 @@ The project is developed using IDEA. Please manually configure the build to not
 Due to me adding in ItemStackMap, which was derived from code from CodeChicken's LGPL mod NEI. This mod is effectively considered
 licensed under LGPL in its entirety since commit ebef584b8c518f8202cfe0984fb28a6d23e52b3d or any squash commit containing it, e.g.
 609e50428ee4e293f65f67f554a70b9fcfae97c4.
+
+Note while the LICENSE.txt is added by a much later commit, all code on previous commits are covered by this as well.

addon.gradle

@@ -1,4 +1,10 @@
 javadoc {
+    javadocTool = javaToolchains.javadocToolFor {
+        // Last version with frames, but it also has search
+        languageVersion = JavaLanguageVersion.of(11)
+        vendor = JvmVendorSpec.ADOPTIUM
+    }
+
     inputs.file  "src/main/javadoc/overview.html"
 
     include "com/gtnewhorizon/structurelib/alignment/**"
@@ -6,19 +12,31 @@ javadoc {
     include "com/gtnewhorizon/structurelib/structure/**"
     include "com/gtnewhorizon/structurelib/util/**"
     include "com/gtnewhorizon/structurelib/StructureLibAPI.java"
+    include "com/gtnewhorizon/structurelib/StructureEvent.java"
+
+    classpath += sourceSets.patchedMc.output
 
     options {
         overview "src/main/javadoc/overview.html"
         links 'https://docs.oracle.com/javase/8/docs/api/'
         links 'https://skmedix.github.io/ForgeJavaDocs/javadoc/forge/1.7.10-10.13.4.1614/'
+        addBooleanOption("-frames", true)
     }
 }
 
-task javadocJar(type: Jar, dependsOn: javadoc) {
-    classifier = 'javadoc'
+tasks.register('javadocJar', Jar) {
+    dependsOn javadoc
+    archiveClassifier = 'javadoc'
     from javadoc.destinationDir
 }
 
 artifacts {
     archives javadocJar
 }
+
+test {
+    useJUnitPlatform()
+    testLogging {
+        events "passed", "skipped", "failed"
+    }
+}

dependencies.gradle

@@ -1,6 +1,9 @@
 // Add your dependencies here
 
 dependencies {
-    compile("com.github.GTNewHorizons:GTNHLib:0.0.1:dev")
-    runtime("com.github.GTNewHorizons:NotEnoughItems:2.2.20-GTNH:dev")
+    api("com.github.GTNewHorizons:GTNHLib:0.0.10:dev")
+    runtimeOnly("com.github.GTNewHorizons:NotEnoughItems:2.3.46-GTNH:dev")
+
+    testImplementation(platform('org.junit:junit-bom:5.9.2'))
+    testImplementation('org.junit.jupiter:junit-jupiter')
 }

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.9.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.6-bin.zip
+networkTimeout=10000
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

gradlew

@@ -1,7 +1,7 @@
-#!/usr/bin/env sh
+#!/bin/sh
 
 #
-# Copyright 2015 the original author or authors.
+# Copyright © 2015-2021 the original authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -17,78 +17,113 @@
 #
 
 ##############################################################################
-##
-##  Gradle start up script for UN*X
-##
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
 ##############################################################################
 
 # Attempt to set APP_HOME
-# Resolve links: $0 may be a link
-PRG="$0"
-# Need this for relative symlinks.
-while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-        PRG="$link"
-    else
-        PRG=`dirname "$PRG"`"/$link"
-    fi
-done
-SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >/dev/null
-APP_HOME="`pwd -P`"
-cd "$SAVED" >/dev/null
 
-APP_NAME="Gradle"
-APP_BASE_NAME=`basename "$0"`
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
 
 # Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
 DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
-MAX_FD="maximum"
+MAX_FD=maximum
 
 warn () {
     echo "$*"
-}
+} >&2
 
 die () {
     echo
     echo "$*"
     echo
     exit 1
-}
+} >&2
 
 # OS specific support (must be 'true' or 'false').
 cygwin=false
 msys=false
 darwin=false
 nonstop=false
-case "`uname`" in
-  CYGWIN* )
-    cygwin=true
-    ;;
-  Darwin* )
-    darwin=true
-    ;;
-  MINGW* )
-    msys=true
-    ;;
-  NONSTOP* )
-    nonstop=true
-    ;;
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
+
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
     if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
         # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD="$JAVA_HOME/jre/sh/java"
+        JAVACMD=$JAVA_HOME/jre/sh/java
     else
-        JAVACMD="$JAVA_HOME/bin/java"
+        JAVACMD=$JAVA_HOME/bin/java
     fi
     if [ ! -x "$JAVACMD" ] ; then
         die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
@@ -97,7 +132,7 @@ Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
     fi
 else
-    JAVACMD="java"
+    JAVACMD=java
     which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
 
 Please set the JAVA_HOME variable in your environment to match the
@@ -105,84 +140,105 @@ location of your Java installation."
 fi
 
 # Increase the maximum file descriptors if we can.
-if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
-    MAX_FD_LIMIT=`ulimit -H -n`
-    if [ $? -eq 0 ] ; then
-        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
-            MAX_FD="$MAX_FD_LIMIT"
-        fi
-        ulimit -n $MAX_FD
-        if [ $? -ne 0 ] ; then
-            warn "Could not set maximum file descriptor limit: $MAX_FD"
-        fi
-    else
-        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
-    fi
-fi
-
-# For Darwin, add options to specify how the application appears in the dock
-if $darwin; then
-    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
-fi
-
-# For Cygwin or MSYS, switch paths to Windows format before running java
-if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
-    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
-    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
-    JAVACMD=`cygpath --unix "$JAVACMD"`
-
-    # We build the pattern for arguments to be converted via cygpath
-    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
-    SEP=""
-    for dir in $ROOTDIRSRAW ; do
-        ROOTDIRS="$ROOTDIRS$SEP$dir"
-        SEP="|"
-    done
-    OURCYGPATTERN="(^($ROOTDIRS))"
-    # Add a user-defined pattern to the cygpath arguments
-    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
-        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
-    fi
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    i=0
-    for arg in "$@" ; do
-        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
-        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
-
-        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
-            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
-        else
-            eval `echo args$i`="\"$arg\""
-        fi
-        i=$((i+1))
-    done
-    case $i in
-        (0) set -- ;;
-        (1) set -- "$args0" ;;
-        (2) set -- "$args0" "$args1" ;;
-        (3) set -- "$args0" "$args1" "$args2" ;;
-        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
     esac
 fi
 
-# Escape application args
-save () {
-    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
-    echo " "
-}
-APP_ARGS=$(save "$@")
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
 
-# Collect all arguments for the java command, following the shell quoting and substitution rules
-eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
-# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
-if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
-  cd "$(dirname "$0")"
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
 fi
 
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
 exec "$JAVACMD" "$@"

gradlew.bat

@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,10 +25,14 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
 set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
@@ -37,7 +41,7 @@ if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto init
+if %ERRORLEVEL% equ 0 goto execute
 
 echo.
 echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
@@ -51,7 +55,7 @@ goto fail
 set JAVA_HOME=%JAVA_HOME:"=%
 set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
-if exist "%JAVA_EXE%" goto init
+if exist "%JAVA_EXE%" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
@@ -61,38 +65,26 @@ echo location of your Java installation.
 
 goto fail
 
-:init
-@rem Get command-line arguments, handling Windows variants
-
-if not "%OS%" == "Windows_NT" goto win9xME_args
-
-:win9xME_args
-@rem Slurp the command line arguments.
-set CMD_LINE_ARGS=
-set _SKIP=2
-
-:win9xME_args_slurp
-if "x%~1" == "x" goto execute
-
-set CMD_LINE_ARGS=%*
-
 :execute
 @rem Setup the command line
 
 set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
+
 @rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal

settings.gradle

@@ -1,10 +1,28 @@
+
+pluginManagement {
+    repositories {
+        maven {
+            // RetroFuturaGradle
+            name "GTNH Maven"
+            url "http://jenkins.usrv.eu:8081/nexus/content/groups/public/"
+            allowInsecureProtocol = true
+            mavenContent {
+                includeGroup("com.gtnewhorizons.retrofuturagradle")
+            }
+        }
+        gradlePluginPortal()
+        mavenCentral()
+        mavenLocal()
+    }
+}
+
 plugins {
     id 'com.diffplug.blowdryerSetup' version '1.6.0'
+    id 'org.gradle.toolchains.foojay-resolver-convention' version '0.4.0' // Provides java toolchains
 }
 
-apply plugin: 'com.diffplug.blowdryerSetup'
-
 blowdryerSetup {
-    github('GTNewHorizons/ExampleMod1.7.10', 'tag', '0.1.4')
+    repoSubfolder 'gtnhShared'
+    github('GTNewHorizons/ExampleMod1.7.10', 'tag', '0.2.0')
     //devLocal '.' // Use this when testing config updates locally
 }

src/main/java/com/gtnewhorizon/structurelib/ClientProxy.java

@@ -2,21 +2,14 @@ package com.gtnewhorizon.structurelib;
 
 import static com.gtnewhorizon.structurelib.StructureLib.RANDOM;
 
-import com.gtnewhorizon.structurelib.entity.fx.WeightlessParticleFX;
-import com.gtnewhorizon.structurelib.net.SetChannelDataMessage;
-import cpw.mods.fml.common.FMLCommonHandler;
-import cpw.mods.fml.common.event.FMLPreInitializationEvent;
-import cpw.mods.fml.common.eventhandler.SubscribeEvent;
-import cpw.mods.fml.common.gameevent.TickEvent.ClientTickEvent;
-import cpw.mods.fml.common.gameevent.TickEvent.Phase;
 import java.util.*;
+
 import net.minecraft.block.Block;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.GuiNewChat;
 import net.minecraft.client.particle.EntityFX;
 import net.minecraft.client.renderer.Tessellator;
 import net.minecraft.client.renderer.culling.Frustrum;
-import net.minecraft.client.renderer.entity.RenderManager;
 import net.minecraft.client.renderer.texture.TextureMap;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.player.EntityPlayer;
@@ -31,19 +24,28 @@ import net.minecraft.world.World;
 import net.minecraftforge.client.event.RenderWorldLastEvent;
 import net.minecraftforge.common.MinecraftForge;
 import net.minecraftforge.event.world.WorldEvent;
+
 import org.lwjgl.opengl.GL11;
 
+import com.gtnewhorizon.structurelib.entity.fx.WeightlessParticleFX;
+import com.gtnewhorizon.structurelib.net.SetChannelDataMessage;
+
+import cpw.mods.fml.common.FMLCommonHandler;
+import cpw.mods.fml.common.event.FMLPreInitializationEvent;
+import cpw.mods.fml.common.eventhandler.SubscribeEvent;
+import cpw.mods.fml.common.gameevent.TickEvent.ClientTickEvent;
+import cpw.mods.fml.common.gameevent.TickEvent.Phase;
+
 public class ClientProxy extends CommonProxy {
 
-    private static final short[] RGBA_NO_TINT = {255, 255, 255, 255};
-    private static final short[] RGBA_RED_TINT = {255, 128, 128, 0};
+    private static final short[] RGBA_NO_TINT = { 255, 255, 255, 255 };
+    private static final short[] RGBA_RED_TINT = { 255, 128, 128, 0 };
     private static final Map<HintParticleInfo, HintGroup> allHints = new HashMap<>();
     /**
      * All batches of hints.
      */
     private static final List<HintGroup> allGroups = new ArrayList<>();
 
-    public static int HOLOGRAM_LIFETIME = 200;
     /**
      * Current batch of hints. Belongs to the same logical multiblock.
      */
@@ -55,11 +57,10 @@ public class ClientProxy extends CommonProxy {
      */
     private static final List<HintParticleInfo> allHintsForRender = new ArrayList<>(10000);
     /**
-     * If the diff to current player position is too great sort the allHints.
-     * Initial value is very far off below y=0 but not huge enough to make a NaN.
+     * If the diff to current player position is too great sort the allHints. Initial value is very far off below y=0
+     * but not huge enough to make a NaN.
      * <p>
-     * We are using this supposedly immutable object as a mutable object here.
-     * So be aware.
+     * We are using this supposedly immutable object as a mutable object here. So be aware.
      */
     private static final Vec3 lastPlayerPos = Vec3.createVectorHelper(0, -1e30, 0);
     /**
@@ -158,11 +159,7 @@ public class ClientProxy extends CommonProxy {
     }
 
     @Override
-    public void addThrottledChat(
-            Object throttleKey,
-            EntityPlayer player,
-            IChatComponent text,
-            short intervalRequired,
+    public void addThrottledChat(Object throttleKey, EntityPlayer player, IChatComponent text, short intervalRequired,
             boolean forceUpdateLastSend) {
         if (player instanceof EntityPlayerMP)
             super.addThrottledChat(throttleKey, player, text, intervalRequired, forceUpdateLastSend);
@@ -250,6 +247,7 @@ public class ClientProxy extends CommonProxy {
     }
 
     private static class HintGroup {
+
         private final List<HintParticleInfo> hints = new LinkedList<>();
         private int creationTime = -1;
 
@@ -267,9 +265,10 @@ public class ClientProxy extends CommonProxy {
     }
 
     private static class HintParticleInfo {
+
         private final World w;
+        // these are the block coordinate for e.g. w.getBlock()
         private final int x, y, z;
-        private final double X, Y, Z;
         private final IIcon[] icons;
         private short[] tint;
         private boolean renderThrough;
@@ -281,9 +280,6 @@ public class ClientProxy extends CommonProxy {
             this.x = x;
             this.y = y;
             this.z = z;
-            X = x + 0.25;
-            Y = y + 0.25;
-            Z = z + 0.25;
             this.icons = icons;
             this.tint = tint;
         }
@@ -319,10 +315,11 @@ public class ClientProxy extends CommonProxy {
         }
 
         public boolean isInFrustrum(Frustrum frustrum) {
-            return frustrum.isBoxInFrustum(x, y, z, X, Y, Z);
+            return frustrum.isBoxInFrustum(x + 0.25, y + 0.25, z + 0.25, x + 0.75, y + 0.75, z + 0.75);
         }
 
-        public void draw(Tessellator tes) {
+        public void draw(Tessellator tes, double eyeX, double eyeY, double eyeZ, int eyeXint, int eyeYint,
+                int eyeZint) {
             double size = 0.5;
 
             int brightness = w.blockExists(x, 0, z) ? w.getLightBrightnessForSkyBlocks(x, y, z, 0) : 0;
@@ -334,52 +331,94 @@ public class ClientProxy extends CommonProxy {
                     (int) (tint[2] * 1F),
                     ConfigurationHandler.INSTANCE.getHintTransparency());
 
-            for (int i = 0; i < 6; i++) {
-                if (icons[i] == null) continue;
+            double X = (x - eyeXint) + 0.25;
+            double Y = (y - eyeYint) + 0.25;
+            double Z = (z - eyeZint) + 0.25;
+            double worldX = x + 0.25;
+            double worldY = y + 0.25;
+            double worldZ = z + 0.25;
 
-                markTextureUsed(icons[i]);
+            // this rendering code is independently written by glee8e on July 10th, 2023
+            // and is released as part of StructureLib under LGPL terms, just like everything else in this project
+            // cube is a very special model. its facings can be rendered correctly by viewer distance without using
+            // surface normals and view vector
+            // here we do a 2 pass render.
+            // first pass we draw obstructed faces (i.e. faces that are further away from player)
+            // second pass we draw unobstructed faces
+            for (int j = 0; j < 2; j++) {
+                boolean unobstructedPass = j == 1;
+                for (int i = 0; i < 6; i++) {
+                    if (icons[i] == null) continue;
 
-                double u = icons[i].getMinU();
-                double U = icons[i].getMaxU();
-                double v = icons[i].getMinV();
-                double V = icons[i].getMaxV();
-                switch (i) { // {DOWN, UP, NORTH, SOUTH, WEST, EAST}
-                    case 0:
-                        tes.addVertexWithUV(X, Y, Z + size, u, V);
-                        tes.addVertexWithUV(X, Y, Z, u, v);
-                        tes.addVertexWithUV(X + size, Y, Z, U, v);
-                        tes.addVertexWithUV(X + size, Y, Z + size, U, V);
-                        break;
-                    case 1:
-                        tes.addVertexWithUV(X, Y + size, Z, u, v);
-                        tes.addVertexWithUV(X, Y + size, Z + size, u, V);
-                        tes.addVertexWithUV(X + size, Y + size, Z + size, U, V);
-                        tes.addVertexWithUV(X + size, Y + size, Z, U, v);
-                        break;
-                    case 2:
-                        tes.addVertexWithUV(X, Y, Z, U, V);
-                        tes.addVertexWithUV(X, Y + size, Z, U, v);
-                        tes.addVertexWithUV(X + size, Y + size, Z, u, v);
-                        tes.addVertexWithUV(X + size, Y, Z, u, V);
-                        break;
-                    case 3:
-                        tes.addVertexWithUV(X + size, Y, Z + size, U, V);
-                        tes.addVertexWithUV(X + size, Y + size, Z + size, U, v);
-                        tes.addVertexWithUV(X, Y + size, Z + size, u, v);
-                        tes.addVertexWithUV(X, Y, Z + size, u, V);
-                        break;
-                    case 4:
-                        tes.addVertexWithUV(X, Y, Z + size, U, V);
-                        tes.addVertexWithUV(X, Y + size, Z + size, U, v);
-                        tes.addVertexWithUV(X, Y + size, Z, u, v);
-                        tes.addVertexWithUV(X, Y, Z, u, V);
-                        break;
-                    case 5:
-                        tes.addVertexWithUV(X + size, Y, Z, U, V);
-                        tes.addVertexWithUV(X + size, Y + size, Z, U, v);
-                        tes.addVertexWithUV(X + size, Y + size, Z + size, u, v);
-                        tes.addVertexWithUV(X + size, Y, Z + size, u, V);
-                        break;
+                    markTextureUsed(icons[i]);
+
+                    double u = icons[i].getMinU();
+                    double U = icons[i].getMaxU();
+                    double v = icons[i].getMinV();
+                    double V = icons[i].getMaxV();
+                    switch (i) { // {DOWN, UP, NORTH, SOUTH, WEST, EAST}
+                        case 0:
+                            // all these ifs is in form if ((is face unobstructed) != (is in unobstructred pass))
+                            if ((worldY >= eyeY) != unobstructedPass) continue;
+                            tes.setNormal(0, -1, 0);
+                            tes.addVertexWithUV(X, Y, Z + size, u, V);
+                            tes.addVertexWithUV(X, Y, Z, u, v);
+                            tes.addVertexWithUV(X + size, Y, Z, U, v);
+                            tes.addVertexWithUV(X + size, Y, Z, U, v);
+                            tes.addVertexWithUV(X + size, Y, Z + size, U, V);
+                            tes.addVertexWithUV(X, Y, Z + size, u, V);
+                            break;
+                        case 1:
+                            if ((worldY + size <= eyeY) != unobstructedPass) continue;
+                            tes.setNormal(0, 1, 0);
+                            tes.addVertexWithUV(X, Y + size, Z, u, v);
+                            tes.addVertexWithUV(X, Y + size, Z + size, u, V);
+                            tes.addVertexWithUV(X + size, Y + size, Z + size, U, V);
+                            tes.addVertexWithUV(X + size, Y + size, Z + size, U, V);
+                            tes.addVertexWithUV(X + size, Y + size, Z, U, v);
+                            tes.addVertexWithUV(X, Y + size, Z, u, v);
+                            break;
+                        case 2:
+                            if ((worldZ >= eyeZ) != unobstructedPass) continue;
+                            tes.setNormal(0, 0, -1);
+                            tes.addVertexWithUV(X, Y, Z, U, V);
+                            tes.addVertexWithUV(X, Y + size, Z, U, v);
+                            tes.addVertexWithUV(X + size, Y + size, Z, u, v);
+                            tes.addVertexWithUV(X + size, Y + size, Z, u, v);
+                            tes.addVertexWithUV(X + size, Y, Z, u, V);
+                            tes.addVertexWithUV(X, Y, Z, U, V);
+                            break;
+                        case 3:
+                            if ((worldZ + size <= eyeZ) != unobstructedPass) continue;
+                            tes.setNormal(0, 0, 1);
+                            tes.addVertexWithUV(X + size, Y, Z + size, U, V);
+                            tes.addVertexWithUV(X + size, Y + size, Z + size, U, v);
+                            tes.addVertexWithUV(X, Y + size, Z + size, u, v);
+                            tes.addVertexWithUV(X, Y + size, Z + size, u, v);
+                            tes.addVertexWithUV(X, Y, Z + size, u, V);
+                            tes.addVertexWithUV(X + size, Y, Z + size, U, V);
+                            break;
+                        case 4:
+                            if ((worldX >= eyeX) != unobstructedPass) continue;
+                            tes.setNormal(-1, 0, 0);
+                            tes.addVertexWithUV(X, Y, Z + size, U, V);
+                            tes.addVertexWithUV(X, Y + size, Z + size, U, v);
+                            tes.addVertexWithUV(X, Y + size, Z, u, v);
+                            tes.addVertexWithUV(X, Y + size, Z, u, v);
+                            tes.addVertexWithUV(X, Y, Z, u, V);
+                            tes.addVertexWithUV(X, Y, Z + size, U, V);
+                            break;
+                        case 5:
+                            if ((worldX + size <= eyeX) != unobstructedPass) continue;
+                            tes.setNormal(1, 0, 0);
+                            tes.addVertexWithUV(X + size, Y, Z, U, V);
+                            tes.addVertexWithUV(X + size, Y + size, Z, U, v);
+                            tes.addVertexWithUV(X + size, Y + size, Z + size, u, v);
+                            tes.addVertexWithUV(X + size, Y + size, Z + size, u, v);
+                            tes.addVertexWithUV(X + size, Y, Z + size, u, V);
+                            tes.addVertexWithUV(X + size, Y, Z, U, V);
+                            break;
+                    }
                 }
             }
         }
@@ -389,11 +428,12 @@ public class ClientProxy extends CommonProxy {
         }
 
         public double getSquareDistanceTo(Vec3 point) {
-            return point.squareDistanceTo(X, Y, Z);
+            return point.squareDistanceTo(x + 0.5, y + 0.5, z + 0.5);
         }
     }
 
     public static class FMLEventHandler {
+
         private void resetPlayerLocation() {
             lastPlayerPos.xCoord = Minecraft.getMinecraft().thePlayer.posX;
             lastPlayerPos.yCoord = Minecraft.getMinecraft().thePlayer.posY;
@@ -430,12 +470,11 @@ public class ClientProxy extends CommonProxy {
                     for (HintGroup c : allGroups) allHintsForRender.addAll(c.getHints());
                     sortRequired = true;
                 }
-                if (renderThrough > 0 && (sortRequired || playerPos.squareDistanceTo(lastPlayerPos) > 1e-2)) {
-                    // only sort if there is anything that need depth test disabled
+                if (sortRequired || playerPos.squareDistanceTo(lastPlayerPos) > 1e-2) {
                     // only redo sort if player moved some distance
                     // default is 0.1 block
                     // if there was a full rebuild, go sort it as well
-                    allHintsForRender.sort(Comparator.comparingDouble(info -> info.getSquareDistanceTo(playerPos)));
+                    allHintsForRender.sort(Comparator.comparingDouble(info -> -info.getSquareDistanceTo(playerPos)));
                     resetPlayerLocation();
                 }
             }
@@ -443,6 +482,7 @@ public class ClientProxy extends CommonProxy {
     }
 
     public static class ForgeEventHandler {
+
         @SubscribeEvent
         public void onWorldLoad(WorldEvent.Load e) {
             if (e.world.isRemote) {
@@ -475,35 +515,47 @@ public class ClientProxy extends CommonProxy {
                     + (entitylivingbase.posY - entitylivingbase.lastTickPosY) * e.partialTicks;
             double d2 = entitylivingbase.lastTickPosZ
                     + (entitylivingbase.posZ - entitylivingbase.lastTickPosZ) * e.partialTicks;
+            int i0 = (int) d0, i1 = (int) d1, i2 = (int) d2;
             frustrum.setPosition(d0, d1, d2);
 
             GL11.glPushMatrix();
             GL11.glPushAttrib(GL11.GL_ENABLE_BIT | GL11.GL_COLOR_BUFFER_BIT); // TODO figure out original states
             // we need the back facing rendered because the thing is transparent
             GL11.glDisable(GL11.GL_CULL_FACE);
+            GL11.glDisable(GL11.GL_ALPHA_TEST);
             GL11.glEnable(GL11.GL_BLEND); // enable blend so it is transparent
             GL11.glBlendFunc(GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.GL_SRC_ALPHA);
             // depth test begin as enabled
             boolean renderThrough = false;
             Minecraft.getMinecraft().renderEngine.bindTexture(TextureMap.locationBlocksTexture);
-            GL11.glTranslated(-RenderManager.renderPosX, -RenderManager.renderPosY, -RenderManager.renderPosZ);
+            GL11.glTranslated(-d0 + i0, -d1 + i1, -d2 + i2);
             Tessellator tes = Tessellator.instance;
-            tes.startDrawingQuads();
-            for (int i = 0, allHintsForRenderSize = allHintsForRender.size(); i < allHintsForRenderSize; i++) {
+            tes.startDrawing(GL11.GL_TRIANGLES);
+            for (int i = 0, allHintsForRenderSize = allHintsForRender.size(), cubeDrawn = 0; i
+                    < allHintsForRenderSize; i++, cubeDrawn++) {
                 HintParticleInfo hint = allHintsForRender.get(i);
                 if (!hint.isInFrustrum(frustrum)) continue;
                 if (renderThrough != hint.renderThrough) {
                     if (i > 0) {
                         p.endStartSection("Draw");
                         tes.draw();
-                        tes.startDrawingQuads();
+                        tes.startDrawing(GL11.GL_TRIANGLES);
+                        cubeDrawn = 0;
                         p.endStartSection("Prepare");
                     }
                     if (hint.renderThrough) GL11.glDisable(GL11.GL_DEPTH_TEST);
                     else GL11.glEnable(GL11.GL_DEPTH_TEST);
                     renderThrough = hint.renderThrough;
                 }
-                hint.draw(tes);
+                // Minecraft Tessellator draw in batch of 4096. This plays nicely with quads, but for trigs
+                // it might occasionally end up with one half in first batch and the other half in later batch.
+                // so we manually flush the buffer here if that would happen.
+                // 6 faces per particle, 2 trig per face, 3 vertex per trig
+                if ((cubeDrawn + 1) >= 4096 / (6 * 2 * 3)) {
+                    tes.draw();
+                    tes.startDrawing(GL11.GL_TRIANGLES);
+                }
+                hint.draw(tes, d0, d1, d2, i0, i1, i2);
             }
             p.endStartSection("Draw");
             tes.draw();

src/main/java/com/gtnewhorizon/structurelib/CommonProxy.java

@@ -1,11 +1,9 @@
 package com.gtnewhorizon.structurelib;
 
-import com.gtnewhorizon.structurelib.net.ErrorHintParticleMessage;
-import com.gtnewhorizon.structurelib.net.UpdateHintParticleMessage;
-import cpw.mods.fml.common.event.FMLPreInitializationEvent;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.WeakHashMap;
+
 import net.minecraft.block.Block;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.entity.player.EntityPlayerMP;
@@ -15,7 +13,12 @@ import net.minecraft.util.IChatComponent;
 import net.minecraft.util.IIcon;
 import net.minecraft.world.World;
 
+import com.gtnewhorizon.structurelib.net.ErrorHintParticleMessage;
+import com.gtnewhorizon.structurelib.net.UpdateHintParticleMessage;
+import cpw.mods.fml.common.event.FMLPreInitializationEvent;
+
 public class CommonProxy {
+
     public void hintParticleTinted(World w, int x, int y, int z, IIcon[] icons, short[] RGBa) {}
 
     public void hintParticleTinted(World w, int x, int y, int z, Block block, int meta, short[] RGBa) {}
@@ -68,11 +71,7 @@ public class CommonProxy {
 
     private final Map<EntityPlayerMP, Map<Object, Long>> throttleMap = new WeakHashMap<>();
 
-    public void addThrottledChat(
-            Object throttleKey,
-            EntityPlayer player,
-            IChatComponent text,
-            short intervalRequired,
+    public void addThrottledChat(Object throttleKey, EntityPlayer player, IChatComponent text, short intervalRequired,
             boolean forceUpdateLastSend) {
         if (player instanceof EntityPlayerMP) {
             Map<Object, Long> submap = throttleMap.computeIfAbsent((EntityPlayerMP) player, p -> new HashMap<>());
@@ -80,13 +79,8 @@ public class CommonProxy {
         }
     }
 
-    protected static void addThrottledChat(
-            Object throttleKey,
-            EntityPlayer player,
-            IChatComponent text,
-            short intervalRequired,
-            boolean forceUpdateLastSend,
-            Map<Object, Long> submap) {
+    protected static void addThrottledChat(Object throttleKey, EntityPlayer player, IChatComponent text,
+            short intervalRequired, boolean forceUpdateLastSend, Map<Object, Long> submap) {
         long now = System.currentTimeMillis();
         Long old;
         if (forceUpdateLastSend) {

src/main/java/com/gtnewhorizon/structurelib/ConfigurationHandler.java

@@ -1,15 +1,18 @@
 package com.gtnewhorizon.structurelib;
 
-import cpw.mods.fml.client.event.ConfigChangedEvent;
-import cpw.mods.fml.common.FMLCommonHandler;
-import cpw.mods.fml.common.eventhandler.SubscribeEvent;
 import java.io.File;
 import java.util.Map;
+
 import net.minecraftforge.common.config.ConfigCategory;
 import net.minecraftforge.common.config.Configuration;
 import net.minecraftforge.common.config.Property;
 
+import cpw.mods.fml.client.event.ConfigChangedEvent;
+import cpw.mods.fml.common.FMLCommonHandler;
+import cpw.mods.fml.common.eventhandler.SubscribeEvent;
+
 public enum ConfigurationHandler {
+
     INSTANCE;
 
     private Configuration config;
@@ -54,8 +57,8 @@ public enum ConfigurationHandler {
                 "client.hologram",
                 true,
                 "An attempt will be made to remove an existing hologram if it collides with a new hologram.");
-        hintLifespan =
-                config.getInt("hintLifespan", "client.hologram", 400, 1, 20000, "Ticks before a hologram disappears.");
+        hintLifespan = config
+                .getInt("hintLifespan", "client.hologram", 400, 1, 20000, "Ticks before a hologram disappears.");
         hintTransparency = config.getInt(
                 "hintTransparency",
                 "client.hologram",
@@ -78,7 +81,7 @@ public enum ConfigurationHandler {
                 300,
                 0,
                 20000,
-                "Unit: milisecond. Minimal interval between two auto place round.\n"
+                "Unit: millisecond. Minimal interval between two auto place round.\n"
                         + "As expected, server side settings will overrides client settings.\n"
                         + "Note this relates to the wall clock, not in game ticks.\n"
                         + "Value smaller than default is likely to be perceived as no minimal interval whatsoever.");

src/main/java/com/gtnewhorizon/structurelib/ConfigurationVersion.java

@@ -2,11 +2,15 @@ package com.gtnewhorizon.structurelib;
 
 import java.util.Arrays;
 import java.util.Objects;
+
 import javax.annotation.Nullable;
+
 import net.minecraftforge.common.config.Configuration;
 
 enum ConfigurationVersion {
+
     V1 {
+
         @Override
         protected void step(Configuration c) {}
     };
@@ -30,10 +34,8 @@ enum ConfigurationVersion {
     }
 
     public static ConfigurationVersion identify(Configuration c) {
-        return Arrays.stream(VALUES)
-                .filter(v -> Objects.equals(c.getLoadedConfigVersion(), v.getVersionMarker()))
-                .findFirst()
-                .orElse(V1);
+        return Arrays.stream(VALUES).filter(v -> Objects.equals(c.getLoadedConfigVersion(), v.getVersionMarker()))
+                .findFirst().orElse(V1);
     }
 
     @Nullable

src/main/java/com/gtnewhorizon/structurelib/GLHelper.java

@@ -1,51 +0,0 @@
-package com.gtnewhorizon.structurelib;
-
-import java.nio.ByteBuffer;
-import org.lwjgl.opengl.ARBVertexBufferObject;
-import org.lwjgl.opengl.ContextCapabilities;
-import org.lwjgl.opengl.GL15;
-import org.lwjgl.opengl.GLContext;
-
-class GLHelper {
-    public static final boolean vboSupported;
-    private static final boolean arbVbo;
-
-    static {
-        ContextCapabilities contextcapabilities = GLContext.getCapabilities();
-
-        arbVbo = !contextcapabilities.OpenGL15 && contextcapabilities.GL_ARB_vertex_buffer_object;
-        vboSupported = contextcapabilities.OpenGL15 || arbVbo;
-    }
-
-    public static int glGenBuffers() {
-        return arbVbo ? ARBVertexBufferObject.glGenBuffersARB() : GL15.glGenBuffers();
-    }
-
-    public static void glBindBuffer(int target, int buffer) {
-        if (arbVbo) {
-            ARBVertexBufferObject.glBindBufferARB(target, buffer);
-        } else {
-            GL15.glBindBuffer(target, buffer);
-        }
-    }
-
-    public static void glBufferData(int target, ByteBuffer data, int usage) {
-        if (arbVbo) {
-            ARBVertexBufferObject.glBufferDataARB(target, data, usage);
-        } else {
-            GL15.glBufferData(target, data, usage);
-        }
-    }
-
-    public static void glDeleteBuffers(int buffer) {
-        if (arbVbo) {
-            ARBVertexBufferObject.glDeleteBuffersARB(buffer);
-        } else {
-            GL15.glDeleteBuffers(buffer);
-        }
-    }
-
-    public static boolean useVbo() {
-        return vboSupported;
-    }
-}

src/main/java/com/gtnewhorizon/structurelib/GuiFactory.java

@@ -1,11 +1,14 @@
 package com.gtnewhorizon.structurelib;
 
-import cpw.mods.fml.client.IModGuiFactory;
 import java.util.Set;
+
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.GuiScreen;
 
+import cpw.mods.fml.client.IModGuiFactory;
+
 public class GuiFactory implements IModGuiFactory {
+
     @Override
     public void initialize(Minecraft minecraftInstance) {}
 

src/main/java/com/gtnewhorizon/structurelib/GuiHandler.java

@@ -1,11 +1,13 @@
 package com.gtnewhorizon.structurelib;
 
-import com.gtnewhorizon.structurelib.gui.GuiScreenConfigureChannels;
-import cpw.mods.fml.common.network.IGuiHandler;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.world.World;
 
+import com.gtnewhorizon.structurelib.gui.GuiScreenConfigureChannels;
+import cpw.mods.fml.common.network.IGuiHandler;
+
 public class GuiHandler implements IGuiHandler {
+
     @Override
     public Object getServerGuiElement(int ID, EntityPlayer player, World world, int x, int y, int z) {
         return null;

src/main/java/com/gtnewhorizon/structurelib/GuiModConfig.java

@@ -1,14 +1,17 @@
 package com.gtnewhorizon.structurelib;
 
-import cpw.mods.fml.client.config.GuiConfig;
-import cpw.mods.fml.client.config.IConfigElement;
 import java.util.List;
 import java.util.stream.Collectors;
+
 import net.minecraft.client.gui.GuiScreen;
 import net.minecraftforge.common.config.ConfigElement;
 import net.minecraftforge.common.config.Configuration;
 
+import cpw.mods.fml.client.config.GuiConfig;
+import cpw.mods.fml.client.config.IConfigElement;
+
 public class GuiModConfig extends GuiConfig {
+
     public GuiModConfig(GuiScreen guiScreen) {
         super(
                 guiScreen,
@@ -16,16 +19,13 @@ public class GuiModConfig extends GuiConfig {
                 StructureLibAPI.MOD_ID,
                 false,
                 false,
-                GuiConfig.getAbridgedConfigPath(
-                        ConfigurationHandler.INSTANCE.getConfig().toString()));
+                GuiConfig.getAbridgedConfigPath(ConfigurationHandler.INSTANCE.getConfig().toString()));
     }
 
     @SuppressWarnings("rawtypes")
     private static List<IConfigElement> getConfigElements() {
         final Configuration config = ConfigurationHandler.INSTANCE.getConfig();
-        return config.getCategoryNames().stream()
-                .filter(name -> name.indexOf('.') == -1)
-                .map(name -> new ConfigElement(config.getCategory(name)))
-                .collect(Collectors.toList());
+        return config.getCategoryNames().stream().filter(name -> name.indexOf('.') == -1)
+                .map(name -> new ConfigElement(config.getCategory(name))).collect(Collectors.toList());
     }
 }

src/main/java/com/gtnewhorizon/structurelib/IStructureCompat.java

@@ -3,5 +3,6 @@ package com.gtnewhorizon.structurelib;
 import net.minecraft.util.IIcon;
 
 public interface IStructureCompat {
+
     void markTextureUsed(IIcon o);
 }

src/main/java/com/gtnewhorizon/structurelib/StructureEvent.java

@@ -0,0 +1,159 @@
+package com.gtnewhorizon.structurelib;
+
+import net.minecraft.world.World;
+import net.minecraftforge.common.MinecraftForge;
+
+import com.gtnewhorizon.structurelib.structure.IStructureElement;
+import cpw.mods.fml.common.eventhandler.Event;
+
+/**
+ * Subscribers are <b>required</b> to not keep reference to these events, nor to depend on values of these events after
+ * the method call returns.
+ * <p>
+ * All of these events will be fired on the {@link net.minecraftforge.common.MinecraftForge#EVENT_BUS}, if they are
+ * enabled by {@link StructureLibAPI#enableInstrument(Object)}.
+ * <p>
+ * All public stuff in this class and its enclosed classes are considered part of the public API. Backwards
+ * compatibility is maintained to the maximum extend possible.
+ */
+public abstract class StructureEvent extends Event {
+
+    /*
+     * In case the event is passed to another thread for processing.
+     */
+    private final Object identifier = StructureLibAPI.instrument.get();
+
+    StructureEvent() {}
+
+    /**
+     * The instrument identifier. Subscribers should filter by these identifiers to prevent listening to a structure
+     * event for other people.
+     */
+    public Object getInstrumentIdentifier() {
+        return identifier;
+    }
+
+    /**
+     * Fired <b>just before</b> any structure element is visited.
+     */
+    public static final class StructureElementVisitedEvent extends StructureEvent {
+
+        private final World world;
+        private final int x, y, z;
+        private final int a, b, c;
+        private final IStructureElement<?> element;
+
+        /**
+         * Fire this event on {@link MinecraftForge#EVENT_BUS} by populating it with given arguments. Do nothing if
+         * instrumenting isn't enabled for current thread.
+         * <p>
+         * Any {@link Exception} thrown by event listeners will be logged and ignored. {@link Error} will be propagated
+         * as is.
+         */
+        public static void fireEvent(World world, int x, int y, int z, int a, int b, int c,
+                IStructureElement<?> element) {
+            if (StructureLibAPI.isInstrumentEnabled()) {
+                try {
+                    MinecraftForge.EVENT_BUS.post(new StructureElementVisitedEvent(world, x, y, z, a, b, c, element));
+                } catch (Exception e) {
+                    // logging is done by event bus, we just ignore the consequence here
+                }
+            }
+        }
+
+        StructureElementVisitedEvent(World world, int x, int y, int z, int a, int b, int c,
+                IStructureElement<?> element) {
+            this.world = world;
+            this.x = x;
+            this.y = y;
+            this.z = z;
+            this.a = a;
+            this.b = b;
+            this.c = c;
+            this.element = element;
+        }
+
+        /**
+         * A position in ABC coordinate, relative to (0,0,0) in the piece, i.e. without baseOffset
+         * <p>
+         * Submit a feature request if you need the baseOffset.
+         */
+        public int getA() {
+            return a;
+        }
+
+        /**
+         * B position in ABC coordinate, relative to (0,0,0) in the piece, i.e. without baseOffset
+         * <p>
+         * Submit a feature request if you need the baseOffset.
+         */
+        public int getB() {
+            return b;
+        }
+
+        /**
+         * C position in ABC coordinate, relative to (0,0,0) in the piece, i.e. without baseOffset
+         * <p>
+         * Submit a feature request if you need the baseOffset.
+         */
+        public int getC() {
+            return c;
+        }
+
+        /**
+         * Element being visited.
+         */
+        public IStructureElement<?> getElement() {
+            return element;
+        }
+
+        @Override
+        public String toString() {
+            return "StructureElementVisitedEvent{" + "a="
+                    + a
+                    + ", b="
+                    + b
+                    + ", c="
+                    + c
+                    + ", element="
+                    + element
+                    + ", world="
+                    + getWorld()
+                    + ", x="
+                    + getX()
+                    + ", y="
+                    + getY()
+                    + ", z="
+                    + getZ()
+                    + '}';
+        }
+
+        /**
+         * Location of this event.
+         */
+        public World getWorld() {
+            return world;
+        }
+
+        /**
+         * Location of this event. Absolute world coordinate.
+         */
+        public int getX() {
+            return x;
+        }
+
+        /**
+         * Location of this event. Absolute world coordinate.
+         */
+        public int getY() {
+            return y;
+        }
+
+        /**
+         * Location of this event. Absolute world coordinate.
+         */
+        public int getZ() {
+            return z;
+        }
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/StructureLib.java

@@ -1,5 +1,15 @@
 package com.gtnewhorizon.structurelib;
 
+import net.minecraft.block.Block;
+import net.minecraft.creativetab.CreativeTabs;
+import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.item.Item;
+import net.minecraft.item.ItemBlock;
+import net.minecraft.launchwrapper.Launch;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
 import com.gtnewhorizon.structurelib.block.BlockHint;
 import com.gtnewhorizon.structurelib.command.CommandConfigureChannels;
 import com.gtnewhorizon.structurelib.item.ItemBlockHint;
@@ -10,6 +20,7 @@ import com.gtnewhorizon.structurelib.net.ErrorHintParticleMessage;
 import com.gtnewhorizon.structurelib.net.SetChannelDataMessage;
 import com.gtnewhorizon.structurelib.net.UpdateHintParticleMessage;
 import com.gtnewhorizon.structurelib.util.XSTR;
+
 import cpw.mods.fml.common.Loader;
 import cpw.mods.fml.common.Mod;
 import cpw.mods.fml.common.SidedProxy;
@@ -20,14 +31,6 @@ import cpw.mods.fml.common.network.simpleimpl.SimpleNetworkWrapper;
 import cpw.mods.fml.common.registry.GameRegistry;
 import cpw.mods.fml.relauncher.Side;
 import cpw.mods.fml.relauncher.SideOnly;
-import net.minecraft.block.Block;
-import net.minecraft.creativetab.CreativeTabs;
-import net.minecraft.entity.player.EntityPlayer;
-import net.minecraft.item.Item;
-import net.minecraft.item.ItemBlock;
-import net.minecraft.launchwrapper.Launch;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 
 /**
  * This class does not contain a stable API. Refrain from using this class.
@@ -39,21 +42,25 @@ import org.apache.logging.log4j.Logger;
         acceptableRemoteVersions = "*",
         guiFactory = "com.gtnewhorizon.structurelib.GuiFactory")
 public class StructureLib {
+
     private static final String STRUCTURECOMPAT_MODID = "structurecompat";
     public static boolean DEBUG_MODE;
     public static boolean PANIC_MODE = Boolean.getBoolean("structurelib.panic");
-    public static Logger LOGGER = LogManager.getLogger("StructureLib");
+    public static final Logger LOGGER = LogManager.getLogger("StructureLib");
 
     @SidedProxy(
             serverSide = "com.gtnewhorizon.structurelib.CommonProxy",
             clientSide = "com.gtnewhorizon.structurelib.ClientProxy")
     static CommonProxy proxy;
 
-    static SimpleNetworkWrapper net = NetworkRegistry.INSTANCE.newSimpleChannel(StructureLibAPI.MOD_ID);
+    static final SimpleNetworkWrapper net = NetworkRegistry.INSTANCE.newSimpleChannel(StructureLibAPI.MOD_ID);
 
     static {
         net.registerMessage(
-                AlignmentMessage.ServerHandler.class, AlignmentMessage.AlignmentQuery.class, 0, Side.SERVER);
+                AlignmentMessage.ServerHandler.class,
+                AlignmentMessage.AlignmentQuery.class,
+                0,
+                Side.SERVER);
         net.registerMessage(AlignmentMessage.ClientHandler.class, AlignmentMessage.AlignmentData.class, 1, Side.CLIENT);
         net.registerMessage(UpdateHintParticleMessage.Handler.class, UpdateHintParticleMessage.class, 2, Side.CLIENT);
         net.registerMessage(SetChannelDataMessage.Handler.class, SetChannelDataMessage.class, 3, Side.SERVER);
@@ -80,6 +87,7 @@ public class StructureLib {
     static Item itemFrontRotationTool;
     static Item itemConstructableTrigger;
     public static final CreativeTabs creativeTab = new CreativeTabs("structurelib") {
+
         @Override
         @SideOnly(Side.CLIENT)
         public Item getTabIconItem() {
@@ -93,7 +101,8 @@ public class StructureLib {
         GameRegistry.registerBlock(blockHint = new BlockHint(), ItemBlockHint.class, "blockhint");
         itemBlockHint = ItemBlock.getItemFromBlock(StructureLibAPI.getBlockHint());
         GameRegistry.registerItem(
-                itemFrontRotationTool = new ItemFrontRotationTool(), itemFrontRotationTool.getUnlocalizedName());
+                itemFrontRotationTool = new ItemFrontRotationTool(),
+                itemFrontRotationTool.getUnlocalizedName());
         GameRegistry.registerItem(
                 itemConstructableTrigger = new ItemConstructableTrigger(),
                 itemConstructableTrigger.getUnlocalizedName());
@@ -101,10 +110,7 @@ public class StructureLib {
         NetworkRegistry.INSTANCE.registerGuiHandler(instance(), new GuiHandler());
 
         if (Loader.isModLoaded(STRUCTURECOMPAT_MODID)) {
-            COMPAT = Loader.instance()
-                    .getIndexedModList()
-                    .get(STRUCTURECOMPAT_MODID)
-                    .getMod();
+            COMPAT = Loader.instance().getIndexedModList().get(STRUCTURECOMPAT_MODID).getMod();
         }
     }
 

src/main/java/com/gtnewhorizon/structurelib/StructureLibAPI.java

@@ -2,12 +2,6 @@ package com.gtnewhorizon.structurelib;
 
 import static com.gtnewhorizon.structurelib.StructureLib.proxy;
 
-import com.gtnewhorizon.structurelib.alignment.IAlignment;
-import com.gtnewhorizon.structurelib.alignment.IAlignmentProvider;
-import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
-import com.gtnewhorizon.structurelib.net.AlignmentMessage;
-import com.gtnewhorizon.structurelib.structure.IItemSource;
-import cpw.mods.fml.common.network.NetworkRegistry;
 import net.minecraft.block.Block;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.entity.player.EntityPlayerMP;
@@ -17,10 +11,20 @@ import net.minecraft.util.IChatComponent;
 import net.minecraft.util.IIcon;
 import net.minecraft.world.World;
 
+import com.gtnewhorizon.structurelib.alignment.IAlignment;
+import com.gtnewhorizon.structurelib.alignment.IAlignmentProvider;
+import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
+import com.gtnewhorizon.structurelib.net.AlignmentMessage;
+import com.gtnewhorizon.structurelib.structure.AutoPlaceEnvironment;
+import com.gtnewhorizon.structurelib.structure.IStructureDefinition;
+import cpw.mods.fml.common.network.NetworkRegistry;
+
 /**
- * A stable interface into the structure lib's internals. Backwards compatibility is maintained to the maximum extend possible.
+ * A stable interface into the structure lib's internals. Backwards compatibility is maintained to the maximum extend
+ * possible.
  */
 public class StructureLibAPI {
+
     public static final String MOD_ID = "structurelib";
     public static final int HINT_BLOCK_META_GENERIC_0 = 0;
     public static final int HINT_BLOCK_META_GENERIC_1 = 1;
@@ -38,20 +42,74 @@ public class StructureLibAPI {
     public static final int HINT_BLOCK_META_AIR = 13;
     public static final int HINT_BLOCK_META_NOT_AIR = 14;
     public static final int HINT_BLOCK_META_ERROR = 15;
+    static final ThreadLocal<Object> instrument = new ThreadLocal<>();
 
     /**
-     * Start a batch of hinting. All hints particles generated during one batch will be considered to belong to one hologram.
+     * Start instrumenting <b>for the current thread only</b>. When instrumentation is enabled,
+     * {@link IStructureDefinition}'s builtin iteration methods will send {@link StructureEvent} and its subclasses when
+     * appropriate. Otherwise, these events will not be sent at all, regardless of whether a listener for these events
+     * are registered.
      * <p>
-     * You don't need to call this unless your constructable tool didn't call {@link com.gtnewhorizon.structurelib.alignment.constructable.ConstructableUtility#handle(ItemStack, EntityPlayer, World, int, int, int, int)}
+     * Identifiers are required to be value-comparable, i.e. overrides {@link Object#equals(Object)}. Suggested
+     * identifier includes
+     * <ul>
+     * <li>Mod Instance or {@link cpw.mods.fml.common.ModContainer}</li>
+     * <li>{@link com.gtnewhorizon.structurelib.alignment.constructable.IConstructable} and its friends, if you are
+     * triggering structure check via this interface.</li>
+     * <li>{@link net.minecraft.util.ResourceLocation}</li>
+     * </ul>
+     * <p>
+     * It's an API abuse for normal {@link IStructureDefinition} users to depend on this feature. They have full control
+     * and full knowledge of the {@link IStructureDefinition} they are using. Using events to instrument the structure
+     * check/autoplace is completely unnecessary and does nothing but add overhead.
+     * <p>
+     * Instruments are required to call {@link #disableInstrument()} whenever it is done with its business, as there can
+     * be only one instrument for any given thread.
+     *
+     * @param identifier an identifier sent along the actual event.
+     * @throws IllegalStateException if instrument has already been enabled.
+     */
+    public static void enableInstrument(Object identifier) {
+        if (isInstrumentEnabled()) throw new IllegalStateException();
+        instrument.set(instrument);
+    }
+
+    /**
+     * Stop instrumenting.
+     *
+     * @throws IllegalStateException if instrumenting hasn't been enabled.
+     */
+    public static void disableInstrument() {
+        if (!isInstrumentEnabled()) throw new IllegalStateException();
+        instrument.set(null);
+    }
+
+    /**
+     * Check if instrumenting is enabled.
+     *
+     * @return true if enabled, false otherwise
+     */
+    public static boolean isInstrumentEnabled() {
+        return instrument.get() != null;
+    }
+
+    /**
+     * Start a batch of hinting. All hints particles generated during one batch will be considered to belong to one
+     * hologram.
+     * <p>
+     * You don't need to call this unless your constructable tool didn't call
+     * {@link com.gtnewhorizon.structurelib.alignment.constructable.ConstructableUtility#handle(ItemStack, EntityPlayer, World, int, int, int, int)}
      */
     public static void startHinting(World w) {
         proxy.startHinting(w);
     }
 
     /**
-     * End current batch of hinting. All hints particles generated during one batch will be considered to belong to one hologram.
+     * End current batch of hinting. All hints particles generated during one batch will be considered to belong to one
+     * hologram.
      * <p>
-     * You don't need to call this unless your constructable tool didn't call {@link com.gtnewhorizon.structurelib.alignment.constructable.ConstructableUtility#handle(ItemStack, EntityPlayer, World, int, int, int, int)}
+     * You don't need to call this unless your constructable tool didn't call
+     * {@link com.gtnewhorizon.structurelib.alignment.constructable.ConstructableUtility#handle(ItemStack, EntityPlayer, World, int, int, int, int)}
      */
     public static void endHinting(World w) {
         proxy.endHinting(w);
@@ -59,12 +117,14 @@ public class StructureLibAPI {
 
     /**
      * Generate a new hint particle on client side at given location using given textures with a tint.
-     * @param w World to spawn. Usually the client world.
-     * @param x x coord
-     * @param y y coord
-     * @param z z coord
+     *
+     * @param w     World to spawn. Usually the client world.
+     * @param x     x coord
+     * @param y     y coord
+     * @param z     z coord
      * @param icons 6 texture. in forge direction order.
-     * @param RGBa a 4 short array. tint in rgba form. currently alpha channel is ignored, but we might change this later on.
+     * @param RGBa  a 4 short array. tint in rgba form. currently alpha channel is ignored, but we might change this
+     *              later on.
      */
     public static void hintParticleTinted(World w, int x, int y, int z, IIcon[] icons, short[] RGBa) {
         proxy.hintParticleTinted(w, x, y, z, icons, RGBa);
@@ -72,13 +132,15 @@ public class StructureLibAPI {
 
     /**
      * Generate a new hint particle on client side at given location using textures from given block with a tint.
-     * @param w World to spawn. Usually the client world.
-     * @param x x coord
-     * @param y y coord
-     * @param z z coord
+     *
+     * @param w     World to spawn. Usually the client world.
+     * @param x     x coord
+     * @param y     y coord
+     * @param z     z coord
      * @param block block to take texture from
-     * @param meta the meta of block to take texture from
-     * @param RGBa a 4 short array. tint in rgba form. currently alpha channel is ignored, but we might change this later on.
+     * @param meta  the meta of block to take texture from
+     * @param RGBa  a 4 short array. tint in rgba form. currently alpha channel is ignored, but we might change this
+     *              later on.
      */
     public static void hintParticleTinted(World w, int x, int y, int z, Block block, int meta, short[] RGBa) {
         proxy.hintParticleTinted(w, x, y, z, block, meta, RGBa);
@@ -86,10 +148,11 @@ public class StructureLibAPI {
 
     /**
      * Generate a new hint particle on client side at given location using given textures.
-     * @param w World to spawn. Usually the client world.
-     * @param x x coord
-     * @param y y coord
-     * @param z z coord
+     *
+     * @param w     World to spawn. Usually the client world.
+     * @param x     x coord
+     * @param y     y coord
+     * @param z     z coord
      * @param icons 6 texture. in forge direction order.
      */
     public static void hintParticle(World w, int x, int y, int z, IIcon[] icons) {
@@ -98,12 +161,13 @@ public class StructureLibAPI {
 
     /**
      * Generate a new hint particle on client side at given location using textures from given block.
-     * @param w World to spawn. Usually the client world.
-     * @param x x coord
-     * @param y y coord
-     * @param z z coord
+     *
+     * @param w     World to spawn. Usually the client world.
+     * @param x     x coord
+     * @param y     y coord
+     * @param z     z coord
      * @param block block to take texture from
-     * @param meta the meta of block to take texture from
+     * @param meta  the meta of block to take texture from
      */
     public static void hintParticle(World w, int x, int y, int z, Block block, int meta) {
         proxy.hintParticle(w, x, y, z, block, meta);
@@ -111,10 +175,9 @@ public class StructureLibAPI {
 
     /**
      * Update the tint of given hint particle. Do nothing if particle not found.
-     *
-     * Can be called on either client side or server side.
-     * Server side will schedule a network message to update it for this player only.
-     * Will do nothing if no hint particle is found at given location.
+     * <p>
+     * Can be called on either client side or server side. Server side will schedule a network message to update it for
+     * this player only. Will do nothing if no hint particle is found at given location.
      *
      * @return false if nothing updated. true if updated or update instruction sent.
      */
@@ -132,11 +195,13 @@ public class StructureLibAPI {
     }
 
     /**
-     * Query the ExtendedFacing of this tile entity from client side. Can be sent only on client side.
-     * The ExtendedFacing will later be set onto given tile entity via {@link com.gtnewhorizon.structurelib.alignment.IAlignment#setExtendedFacing(ExtendedFacing)}
-     * upon arrival of server reply.
+     * Query the ExtendedFacing of this tile entity from client side. Can be sent only on client side. The
+     * ExtendedFacing will later be set onto given tile entity via
+     * {@link com.gtnewhorizon.structurelib.alignment.IAlignment#setExtendedFacing(ExtendedFacing)} upon arrival of
+     * server reply.
      * <p>
-     * The server side will query the {@link ExtendedFacing} of this provider using {@link IAlignment#getExtendedFacing()}
+     * The server side will query the {@link ExtendedFacing} of this provider using
+     * {@link IAlignment#getExtendedFacing()}
      *
      * @throws IllegalArgumentException if is not tile entity or provided a null alignment
      */
@@ -147,7 +212,8 @@ public class StructureLibAPI {
     /**
      * Send the ExtendedFacing of this Tile Entity to all players. Can be called on server side only.
      * <p>
-     * The receiving tile entity will receive the {@link ExtendedFacing} via its {@link com.gtnewhorizon.structurelib.alignment.IAlignment#setExtendedFacing(ExtendedFacing)} method.
+     * The receiving tile entity will receive the {@link ExtendedFacing} via its
+     * {@link com.gtnewhorizon.structurelib.alignment.IAlignment#setExtendedFacing(ExtendedFacing)} method.
      *
      * @throws IllegalArgumentException if is not tile entity or provided a null alignment
      */
@@ -158,7 +224,8 @@ public class StructureLibAPI {
     /**
      * Send the ExtendedFacing of this Tile Entity to given player. Can be called on server side only.
      * <p>
-     * The receiving tile entity will receive the {@link ExtendedFacing} via its {@link com.gtnewhorizon.structurelib.alignment.IAlignment#setExtendedFacing(ExtendedFacing)} method.
+     * The receiving tile entity will receive the {@link ExtendedFacing} via its
+     * {@link com.gtnewhorizon.structurelib.alignment.IAlignment#setExtendedFacing(ExtendedFacing)} method.
      *
      * @throws IllegalArgumentException if is not tile entity or provided a null alignment
      */
@@ -167,9 +234,11 @@ public class StructureLibAPI {
     }
 
     /**
-     * Send the ExtendedFacing of this Tile Entity to all players around target point. Can be called on server side only.
+     * Send the ExtendedFacing of this Tile Entity to all players around target point. Can be called on server side
+     * only.
      * <p>
-     * The receiving tile entity will receive the {@link ExtendedFacing} via its {@link com.gtnewhorizon.structurelib.alignment.IAlignment#setExtendedFacing(ExtendedFacing)} method.
+     * The receiving tile entity will receive the {@link ExtendedFacing} via its
+     * {@link com.gtnewhorizon.structurelib.alignment.IAlignment#setExtendedFacing(ExtendedFacing)} method.
      *
      * @throws IllegalArgumentException if is not tile entity or provided a null alignment
      */
@@ -180,7 +249,8 @@ public class StructureLibAPI {
     /**
      * Send the ExtendedFacing of this Tile Entity to all players in that dimension. Can be called on server side only.
      * <p>
-     * The receiving tile entity will receive the {@link ExtendedFacing} via its {@link com.gtnewhorizon.structurelib.alignment.IAlignment#setExtendedFacing(ExtendedFacing)} method.
+     * The receiving tile entity will receive the {@link ExtendedFacing} via its
+     * {@link com.gtnewhorizon.structurelib.alignment.IAlignment#setExtendedFacing(ExtendedFacing)} method.
      *
      * @throws IllegalArgumentException if is not tile entity or provided a null alignment
      */
@@ -202,6 +272,13 @@ public class StructureLibAPI {
         return StructureLib.itemBlockHint;
     }
 
+    /**
+     * Get the hologram item.
+     */
+    public static Item getDefaultHologramItem() {
+        return StructureLib.itemConstructableTrigger;
+    }
+
     /**
      * Check if structure debug mode is on.
      *
@@ -216,12 +293,25 @@ public class StructureLibAPI {
     }
 
     /**
-     * Determines if given block can be replaced without much effort. The exact predicate clauses is not stable and
-     * will be changed, but the general idea will always stay the same.
+     * Determines if given block can be replaced without much effort. The exact predicate clauses is not stable and will
+     * be changed, but the general idea will always stay the same.
      * <p>
-     * Use this in your {@link com.gtnewhorizon.structurelib.structure.IStructureElement#survivalPlaceBlock(Object, World, int, int, int, ItemStack, IItemSource, EntityPlayerMP, java.util.function.Consumer)}
+     * Use this in your
+     * {@link com.gtnewhorizon.structurelib.structure.IStructureElement#survivalPlaceBlock(Object, World, int, int, int, ItemStack, AutoPlaceEnvironment)}
      */
+    @Deprecated
     public static boolean isBlockTriviallyReplaceable(World w, int x, int y, int z, EntityPlayerMP actor) {
+        return isBlockTriviallyReplaceable(w, x, y, z, (EntityPlayer) actor);
+    }
+
+    /**
+     * Determines if given block can be replaced without much effort. The exact predicate clauses is not stable and will
+     * be changed, but the general idea will always stay the same.
+     * <p>
+     * Use this in your
+     * {@link com.gtnewhorizon.structurelib.structure.IStructureElement#survivalPlaceBlock(Object, World, int, int, int, ItemStack, AutoPlaceEnvironment)}
+     */
+    public static boolean isBlockTriviallyReplaceable(World w, int x, int y, int z, EntityPlayer actor) {
         // TODO extend this function a bit
         Block block = w.getBlock(x, y, z);
         return block.isAir(w, x, y, z) || block.isReplaceable(w, x, y, z);
@@ -229,34 +319,34 @@ public class StructureLibAPI {
 
     /**
      * Send chat to player, but throttled.
-     * @param throttleKey throttle key. Must properly implement {@link Object#hashCode()} and {@link Object#equals(Object)}
-     *                    to handle value equality.
-     * @param player        player to send chat to
-     * @param text          chat to send
-     * @param intervalRequired interval required before last recorded time to actually send the message. unit in millisecond.
-     *                         we purposefully chose to not use a bigger data type to limit how long this interval can be
+     *
+     * @param throttleKey      throttle key. Must properly implement {@link Object#hashCode()} and
+     *                         {@link Object#equals(Object)} to handle value equality.
+     * @param player           player to send chat to
+     * @param text             chat to send
+     * @param intervalRequired interval required before last recorded time to actually send the message. unit in
+     *                         millisecond. we purposefully chose to not use a bigger data type to limit how long this
+     *                         interval can be
      */
-    public static void addThrottledChat(
-            Object throttleKey, EntityPlayer player, IChatComponent text, short intervalRequired) {
+    public static void addThrottledChat(Object throttleKey, EntityPlayer player, IChatComponent text,
+            short intervalRequired) {
         addThrottledChat(throttleKey, player, text, intervalRequired, false);
     }
 
     /**
      * Send chat to player, but throttled.
-     * @param throttleKey throttle key. Must properly implement {@link Object#hashCode()} and {@link Object#equals(Object)}
-     *                    to handle value equality.
-     * @param player        player to send chat to
-     * @param text          chat to send
-     * @param intervalRequired interval required before last recorded time to actually send the message. unit in millisecond.
-     *                         we purposefully chose to not use a bigger data type to limit how long this interval can be
+     *
+     * @param throttleKey         throttle key. Must properly implement {@link Object#hashCode()} and
+     *                            {@link Object#equals(Object)} to handle value equality.
+     * @param player              player to send chat to
+     * @param text                chat to send
+     * @param intervalRequired    interval required before last recorded time to actually send the message. unit in
+     *                            millisecond. we purposefully chose to not use a bigger data type to limit how long
+     *                            this interval can be
      * @param forceUpdateLastSend if true, always update the last send time, even if the message isn't actually sent.
      */
-    public static void addThrottledChat(
-            Object throttleKey,
-            EntityPlayer player,
-            IChatComponent text,
-            short intervalRequired,
-            boolean forceUpdateLastSend) {
+    public static void addThrottledChat(Object throttleKey, EntityPlayer player, IChatComponent text,
+            short intervalRequired, boolean forceUpdateLastSend) {
         proxy.addThrottledChat(throttleKey, player, text, intervalRequired, forceUpdateLastSend);
     }
 }

src/main/java/com/gtnewhorizon/structurelib/alignment/AlignmentLimits.java

@@ -1,8 +1,9 @@
 package com.gtnewhorizon.structurelib.alignment;
 
+import net.minecraftforge.common.util.ForgeDirection;
+
 import com.gtnewhorizon.structurelib.alignment.enumerable.Flip;
 import com.gtnewhorizon.structurelib.alignment.enumerable.Rotation;
-import net.minecraftforge.common.util.ForgeDirection;
 
 class AlignmentLimits implements IAlignmentLimits {
 

src/main/java/com/gtnewhorizon/structurelib/alignment/AlignmentUtility.java

@@ -7,6 +7,7 @@ import net.minecraft.world.World;
 import net.minecraftforge.common.util.FakePlayer;
 
 public class AlignmentUtility {
+
     private AlignmentUtility() {}
 
     public static boolean handle(EntityPlayer aPlayer, World aWorld, int aX, int aY, int aZ) {

src/main/java/com/gtnewhorizon/structurelib/alignment/IAlignment.java

@@ -1,12 +1,14 @@
 package com.gtnewhorizon.structurelib.alignment;
 
+import net.minecraftforge.common.util.ForgeDirection;
+
 import com.gtnewhorizon.structurelib.alignment.enumerable.Direction;
 import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
 import com.gtnewhorizon.structurelib.alignment.enumerable.Flip;
 import com.gtnewhorizon.structurelib.alignment.enumerable.Rotation;
-import net.minecraftforge.common.util.ForgeDirection;
 
 public interface IAlignment extends IAlignmentLimits, IAlignmentProvider {
+
     int DIRECTIONS_COUNT = Direction.VALUES.length;
     int ROTATIONS_COUNT = Rotation.VALUES.length;
     int FLIPS_COUNT = Flip.VALUES.length;
@@ -15,8 +17,8 @@ public interface IAlignment extends IAlignmentLimits, IAlignmentProvider {
     ExtendedFacing getExtendedFacing();
 
     /**
-     * Set the facing without additional checks.
-     * Tools altering facing should use {@link #toolSetExtendedFacing(ExtendedFacing)} instead.
+     * Set the facing without additional checks. Tools altering facing should use
+     * {@link #toolSetExtendedFacing(ExtendedFacing)} instead.
      */
     void setExtendedFacing(ExtendedFacing alignment);
 
@@ -57,9 +59,8 @@ public interface IAlignment extends IAlignmentLimits, IAlignmentProvider {
 
     default boolean toolSetDirection(ForgeDirection direction) {
         if (direction == null || direction == ForgeDirection.UNKNOWN) {
-            for (int i = 0, j = getDirection().ordinal() + 1, valuesLength = Direction.VALUES.length;
-                    i < valuesLength;
-                    i++) {
+            for (int i = 0, j = getDirection().ordinal() + 1, valuesLength = Direction.VALUES.length; i
+                    < valuesLength; i++) {
                 if (toolSetDirection(Direction.VALUES[(j + i) % valuesLength].getForgeDirection())) {
                     return true;
                 }
@@ -97,8 +98,11 @@ public interface IAlignment extends IAlignmentLimits, IAlignmentProvider {
             int rotations = Rotation.VALUES.length;
             for (int ii = 0, jj = getFlip().ordinal(); ii < flips; ii++) {
                 for (int i = 1, j = getRotation().ordinal(); i < rotations; i++) {
-                    if (checkedSetExtendedFacing(ExtendedFacing.of(
-                            getDirection(), Rotation.VALUES[(j + i) % rotations], Flip.VALUES[(jj + ii) % flips]))) {
+                    if (checkedSetExtendedFacing(
+                            ExtendedFacing.of(
+                                    getDirection(),
+                                    Rotation.VALUES[(j + i) % rotations],
+                                    Flip.VALUES[(jj + ii) % flips]))) {
                         return true;
                     }
                 }
@@ -140,9 +144,8 @@ public interface IAlignment extends IAlignmentLimits, IAlignmentProvider {
 
     default boolean toolSetExtendedFacing(ExtendedFacing extendedFacing) {
         if (extendedFacing == null) {
-            for (int i = 0, j = getExtendedFacing().ordinal() + 1, valuesLength = ExtendedFacing.VALUES.length;
-                    i < valuesLength;
-                    i++) {
+            for (int i = 0, j = getExtendedFacing().ordinal() + 1, valuesLength = ExtendedFacing.VALUES.length; i
+                    < valuesLength; i++) {
                 if (checkedSetExtendedFacing(ExtendedFacing.VALUES[(j + i) % valuesLength])) {
                     return true;
                 }
@@ -187,4 +190,28 @@ public interface IAlignment extends IAlignmentLimits, IAlignmentProvider {
         return getAlignmentLimits()
                 .isNewExtendedFacingValid(alignment.getDirection(), alignment.getRotation(), alignment.getFlip());
     }
+
+    /**
+     * Check if this object support a flip change, assuming both direction and rotation is not changed.
+     */
+    default boolean isFlipChangeAllowed() {
+        ExtendedFacing facing = getExtendedFacing();
+        for (Flip flip : Flip.VALUES) {
+            if (flip == getFlip()) continue;
+            if (isNewExtendedFacingValid(facing.with(flip))) return true;
+        }
+        return false;
+    }
+
+    /**
+     * Check if this object support a rotation change, assuming both direction and flip is not changed.
+     */
+    default boolean isRotationChangeAllowed() {
+        ExtendedFacing facing = getExtendedFacing();
+        for (Rotation rotation : Rotation.VALUES) {
+            if (rotation == getRotation()) continue;
+            if (isNewExtendedFacingValid(facing.with(rotation))) return true;
+        }
+        return false;
+    }
 }

src/main/java/com/gtnewhorizon/structurelib/alignment/IAlignmentLimits.java

@@ -2,14 +2,16 @@ package com.gtnewhorizon.structurelib.alignment;
 
 import static com.gtnewhorizon.structurelib.alignment.IAlignment.STATES_COUNT;
 
-import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
-import com.gtnewhorizon.structurelib.alignment.enumerable.Flip;
-import com.gtnewhorizon.structurelib.alignment.enumerable.Rotation;
 import java.util.Arrays;
 import java.util.Optional;
 import java.util.function.Function;
+
 import net.minecraftforge.common.util.ForgeDirection;
 
+import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
+import com.gtnewhorizon.structurelib.alignment.enumerable.Flip;
+import com.gtnewhorizon.structurelib.alignment.enumerable.Rotation;
+
 public interface IAlignmentLimits {
 
     IAlignmentLimits UNLIMITED = (direction, rotation, flip) -> true;
@@ -37,6 +39,7 @@ public interface IAlignmentLimits {
     }
 
     class Builder {
+
         protected final boolean[] validStates = new boolean[STATES_COUNT];
 
         private Builder() {}
@@ -54,15 +57,13 @@ public interface IAlignmentLimits {
         }
 
         public Builder deny(ForgeDirection fd) {
-            ExtendedFacing.getAllWith(fd).stream()
-                    .mapToInt(ExtendedFacing::getIndex)
+            ExtendedFacing.getAllWith(fd).stream().mapToInt(ExtendedFacing::getIndex)
                     .forEach(v -> validStates[v] = false);
             return this;
         }
 
         public Builder allow(ForgeDirection fd) {
-            ExtendedFacing.getAllWith(fd).stream()
-                    .mapToInt(ExtendedFacing::getIndex)
+            ExtendedFacing.getAllWith(fd).stream().mapToInt(ExtendedFacing::getIndex)
                     .forEach(v -> validStates[v] = true);
             return this;
         }
@@ -78,29 +79,25 @@ public interface IAlignmentLimits {
         }
 
         public Builder deny(Rotation fd) {
-            ExtendedFacing.getAllWith(fd).stream()
-                    .mapToInt(ExtendedFacing::getIndex)
+            ExtendedFacing.getAllWith(fd).stream().mapToInt(ExtendedFacing::getIndex)
                     .forEach(v -> validStates[v] = false);
             return this;
         }
 
         public Builder allow(Rotation fd) {
-            ExtendedFacing.getAllWith(fd).stream()
-                    .mapToInt(ExtendedFacing::getIndex)
+            ExtendedFacing.getAllWith(fd).stream().mapToInt(ExtendedFacing::getIndex)
                     .forEach(v -> validStates[v] = true);
             return this;
         }
 
         public Builder deny(Flip fd) {
-            ExtendedFacing.getAllWith(fd).stream()
-                    .mapToInt(ExtendedFacing::getIndex)
+            ExtendedFacing.getAllWith(fd).stream().mapToInt(ExtendedFacing::getIndex)
                     .forEach(v -> validStates[v] = false);
             return this;
         }
 
         public Builder allow(Flip fd) {
-            ExtendedFacing.getAllWith(fd).stream()
-                    .mapToInt(ExtendedFacing::getIndex)
+            ExtendedFacing.getAllWith(fd).stream().mapToInt(ExtendedFacing::getIndex)
                     .forEach(v -> validStates[v] = true);
             return this;
         }
@@ -122,7 +119,7 @@ public interface IAlignmentLimits {
         }
 
         /**
-         * Prefers rotation over flip, so both flip will get translated to opposite rotation and no flip
+         * Prefers rotation to flip, so both flip will get translated to opposite rotation and no flip
          *
          * @param flip the preferred flip to be used Horizontal or vertical
          * @return this

src/main/java/com/gtnewhorizon/structurelib/alignment/IAlignmentProvider.java

@@ -3,6 +3,7 @@ package com.gtnewhorizon.structurelib.alignment;
 import javax.annotation.Nullable;
 
 public interface IAlignmentProvider {
+
     @Nullable
     IAlignment getAlignment();
 }

src/main/java/com/gtnewhorizon/structurelib/alignment/IntegerAxisSwap.java

@@ -2,12 +2,14 @@ package com.gtnewhorizon.structurelib.alignment;
 
 import static java.lang.Math.abs;
 
-import com.gtnewhorizon.structurelib.alignment.enumerable.Direction;
-import com.gtnewhorizon.structurelib.util.Vec3Impl;
 import net.minecraft.util.Vec3;
 import net.minecraftforge.common.util.ForgeDirection;
 
+import com.gtnewhorizon.structurelib.alignment.enumerable.Direction;
+import com.gtnewhorizon.structurelib.util.Vec3Impl;
+
 public class IntegerAxisSwap {
+
     private final Vec3Impl forFirstAxis;
     private final Vec3Impl forSecondAxis;
     private final Vec3Impl forThirdAxis;
@@ -20,61 +22,49 @@ public class IntegerAxisSwap {
                 || abs(this.forFirstAxis.get1()) + abs(this.forSecondAxis.get1()) + abs(this.forThirdAxis.get1()) != 1
                 || abs(this.forFirstAxis.get2()) + abs(this.forSecondAxis.get2()) + abs(this.forThirdAxis.get2())
                         != 1) {
-            throw new IllegalArgumentException("Axis are overlapping/missing! " + forFirstAxis.name()
-                    + " " + forSecondAxis.name()
-                    + " " + forThirdAxis.name());
+            throw new IllegalArgumentException(
+                    "Axis are overlapping/missing! " + forFirstAxis
+                            .name() + " " + forSecondAxis.name() + " " + forThirdAxis.name());
         }
     }
 
     public Vec3Impl translate(Vec3Impl point) {
         return new Vec3Impl(
-                forFirstAxis.get0() * point.get0()
-                        + forFirstAxis.get1() * point.get1()
+                forFirstAxis.get0() * point.get0() + forFirstAxis.get1() * point.get1()
                         + forFirstAxis.get2() * point.get2(),
-                forSecondAxis.get0() * point.get0()
-                        + forSecondAxis.get1() * point.get1()
+                forSecondAxis.get0() * point.get0() + forSecondAxis.get1() * point.get1()
                         + forSecondAxis.get2() * point.get2(),
-                forThirdAxis.get0() * point.get0()
-                        + forThirdAxis.get1() * point.get1()
+                forThirdAxis.get0() * point.get0() + forThirdAxis.get1() * point.get1()
                         + forThirdAxis.get2() * point.get2());
     }
 
     public Vec3Impl inverseTranslate(Vec3Impl point) {
         return new Vec3Impl(
-                forFirstAxis.get0() * point.get0()
-                        + forSecondAxis.get0() * point.get1()
+                forFirstAxis.get0() * point.get0() + forSecondAxis.get0() * point.get1()
                         + forThirdAxis.get0() * point.get2(),
-                forFirstAxis.get1() * point.get0()
-                        + forSecondAxis.get1() * point.get1()
+                forFirstAxis.get1() * point.get0() + forSecondAxis.get1() * point.get1()
                         + forThirdAxis.get1() * point.get2(),
-                forFirstAxis.get2() * point.get0()
-                        + forSecondAxis.get2() * point.get1()
+                forFirstAxis.get2() * point.get0() + forSecondAxis.get2() * point.get1()
                         + forThirdAxis.get2() * point.get2());
     }
 
     public Vec3 translate(Vec3 point) {
         return Vec3.createVectorHelper(
-                forFirstAxis.get0() * point.xCoord
-                        + forFirstAxis.get1() * point.yCoord
+                forFirstAxis.get0() * point.xCoord + forFirstAxis.get1() * point.yCoord
                         + forFirstAxis.get2() * point.zCoord,
-                forSecondAxis.get0() * point.xCoord
-                        + forSecondAxis.get1() * point.yCoord
+                forSecondAxis.get0() * point.xCoord + forSecondAxis.get1() * point.yCoord
                         + forSecondAxis.get2() * point.zCoord,
-                forThirdAxis.get0() * point.xCoord
-                        + forThirdAxis.get1() * point.yCoord
+                forThirdAxis.get0() * point.xCoord + forThirdAxis.get1() * point.yCoord
                         + forThirdAxis.get2() * point.zCoord);
     }
 
     public Vec3 inverseTranslate(Vec3 point) {
         return Vec3.createVectorHelper(
-                forFirstAxis.get0() * point.xCoord
-                        + forSecondAxis.get0() * point.yCoord
+                forFirstAxis.get0() * point.xCoord + forSecondAxis.get0() * point.yCoord
                         + forThirdAxis.get0() * point.zCoord,
-                forFirstAxis.get1() * point.xCoord
-                        + forSecondAxis.get1() * point.yCoord
+                forFirstAxis.get1() * point.xCoord + forSecondAxis.get1() * point.yCoord
                         + forThirdAxis.get1() * point.zCoord,
-                forFirstAxis.get2() * point.xCoord
-                        + forSecondAxis.get2() * point.yCoord
+                forFirstAxis.get2() * point.xCoord + forSecondAxis.get2() * point.yCoord
                         + forThirdAxis.get2() * point.zCoord);
     }
 

src/main/java/com/gtnewhorizon/structurelib/alignment/constructable/ChannelDataAccessor.java

@@ -3,23 +3,27 @@ package com.gtnewhorizon.structurelib.alignment.constructable;
 import static com.gtnewhorizon.structurelib.util.MiscUtils.getTagKeys;
 import static net.minecraftforge.common.util.Constants.NBT.TAG_COMPOUND;
 
-import com.gtnewhorizon.structurelib.StructureLibAPI;
 import java.util.Locale;
 import java.util.Map.Entry;
 import java.util.stream.Stream;
+
 import net.minecraft.init.Items;
 import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.NBTTagCompound;
 import net.minecraftforge.common.util.Constants.NBT;
+
 import org.apache.commons.lang3.StringUtils;
 import org.apache.commons.lang3.tuple.ImmutablePair;
 
+import com.gtnewhorizon.structurelib.StructureLibAPI;
+
 /**
  * Provide accessor methods for channel data from trigger item.
  *
  * <a href="{@docRoot}/overview-summary.html#channels">Channels section on overview</a>
  */
 public class ChannelDataAccessor {
+
     private static final String SECONDARY_HINT_TAG = "channels";
 
     private ChannelDataAccessor() {}
@@ -27,29 +31,25 @@ public class ChannelDataAccessor {
     /**
      * Return a trigger item that
      * <ul>
-     *     <li>Still carry all the subchannel in some unspecified ways</li>
-     *     <li>Have its master channel data replaced with specified subchannel's data</li>
+     * <li>Still carry all the subchannel in some unspecified ways</li>
+     * <li>Have its master channel data replaced with specified subchannel's data</li>
      * </ul>
      *
-     * If given subchannel does not exist, masterStack may or may not be returned to save performance.
-     * Code within StructureLib can depend on this behavior, you cannot.
+     * If given subchannel does not exist, masterStack may or may not be returned to save performance. Code within
+     * StructureLib can depend on this behavior, you cannot.
      *
      * @param masterStack trigger item. can be the return value of another {@link #withChannel(ItemStack, String)} call
-     * @param channel subchannel to use. will use current master channel data instead if this channel does not exist
-     *                Note: all channel identifiers are supposed to be lower case and not empty.
+     * @param channel     subchannel to use. will use current master channel data instead if this channel does not exist
+     *                    Note: all channel identifiers are supposed to be lower case and not empty.
      * @return a trigger item with new master channel
      */
     public static ItemStack withChannel(ItemStack masterStack, String channel) {
         if (StringUtils.isEmpty(channel) || masterStack == null) throw new IllegalArgumentException();
-        if (StructureLibAPI.isDebugEnabled()
-                && !channel.toLowerCase(Locale.ROOT).equals(channel))
+        if (StructureLibAPI.isDebugEnabled() && !channel.toLowerCase(Locale.ROOT).equals(channel))
             throw new IllegalArgumentException("Channel name can be lower case ONLY");
-        if (!masterStack.hasTagCompound()
-                || !masterStack.stackTagCompound.hasKey(SECONDARY_HINT_TAG, TAG_COMPOUND)
-                || !masterStack
-                        .stackTagCompound
-                        .getCompoundTag(SECONDARY_HINT_TAG)
-                        .hasKey(channel, NBT.TAG_INT)) return masterStack;
+        if (!masterStack.hasTagCompound() || !masterStack.stackTagCompound.hasKey(SECONDARY_HINT_TAG, TAG_COMPOUND)
+                || !masterStack.stackTagCompound.getCompoundTag(SECONDARY_HINT_TAG).hasKey(channel, NBT.TAG_INT))
+            return masterStack;
         ItemStack ret = new ItemStack(
                 masterStack.getItem(),
                 masterStack.stackTagCompound.getCompoundTag(SECONDARY_HINT_TAG).getInteger(channel),
@@ -60,6 +60,7 @@ public class ChannelDataAccessor {
 
     /**
      * Check if given trigger item contains any subchannel
+     * 
      * @param masterStack trigger stack to check
      * @return true if contains any subchannel
      */
@@ -70,57 +71,47 @@ public class ChannelDataAccessor {
 
     /**
      * Check if given trigger item contains specified subchannel
+     * 
      * @param masterStack trigger stack to check
-     * @param channel channel identifier.
-     *                Note: all channel identifiers are supposed to be lower case and not empty.
+     * @param channel     channel identifier. Note: all channel identifiers are supposed to be lower case and not empty.
      * @return true if contains specified subchannel
      */
     public static boolean hasSubChannel(ItemStack masterStack, String channel) {
         if (StringUtils.isEmpty(channel) || masterStack == null) throw new IllegalArgumentException();
-        if (StructureLibAPI.isDebugEnabled()
-                && !channel.toLowerCase(Locale.ROOT).equals(channel))
+        if (StructureLibAPI.isDebugEnabled() && !channel.toLowerCase(Locale.ROOT).equals(channel))
             throw new IllegalArgumentException("Channel name can be lower case ONLY");
-        return !channel.isEmpty()
-                && masterStack.hasTagCompound()
+        return !channel.isEmpty() && masterStack.hasTagCompound()
                 && masterStack.stackTagCompound.hasKey(SECONDARY_HINT_TAG, TAG_COMPOUND)
-                && masterStack
-                        .stackTagCompound
-                        .getCompoundTag(SECONDARY_HINT_TAG)
-                        .hasKey(channel, NBT.TAG_INT);
+                && masterStack.stackTagCompound.getCompoundTag(SECONDARY_HINT_TAG).hasKey(channel, NBT.TAG_INT);
     }
 
     /**
      * Get the subchannel data from given trigger item. Will use master channel instead if not present.
+     * 
      * @param masterStack trigger stack to query from
-     * @param channel channel identifier.
-     *                Note: all channel identifiers are supposed to be lower case and not empty.
+     * @param channel     channel identifier. Note: all channel identifiers are supposed to be lower case and not empty.
      * @return channel data
      */
     public static int getChannelData(ItemStack masterStack, String channel) {
         if (StringUtils.isEmpty(channel) || masterStack == null) throw new IllegalArgumentException();
-        if (StructureLibAPI.isDebugEnabled()
-                && !channel.toLowerCase(Locale.ROOT).equals(channel))
+        if (StructureLibAPI.isDebugEnabled() && !channel.toLowerCase(Locale.ROOT).equals(channel))
             throw new IllegalArgumentException("Channel name can be lower case ONLY");
-        if (!masterStack.hasTagCompound()
-                || !masterStack.stackTagCompound.hasKey(SECONDARY_HINT_TAG, TAG_COMPOUND)
-                || !masterStack
-                        .stackTagCompound
-                        .getCompoundTag(SECONDARY_HINT_TAG)
-                        .hasKey(channel, NBT.TAG_INT)) return masterStack.stackSize;
+        if (!masterStack.hasTagCompound() || !masterStack.stackTagCompound.hasKey(SECONDARY_HINT_TAG, TAG_COMPOUND)
+                || !masterStack.stackTagCompound.getCompoundTag(SECONDARY_HINT_TAG).hasKey(channel, NBT.TAG_INT))
+            return masterStack.stackSize;
         return masterStack.stackTagCompound.getCompoundTag(SECONDARY_HINT_TAG).getInteger(channel);
     }
 
     /**
      * Set the subchannel data on given trigger item
+     * 
      * @param masterStack trigger stack to check
-     * @param channel channel identifier.
-     *                Note: all channel identifiers are supposed to be lower case and not empty.
-     * @param data subchannel data. should always be a positive value
+     * @param channel     channel identifier. Note: all channel identifiers are supposed to be lower case and not empty.
+     * @param data        subchannel data. should always be a positive value
      */
     public static void setChannelData(ItemStack masterStack, String channel, int data) {
         if (StringUtils.isEmpty(channel) || masterStack == null) throw new IllegalArgumentException();
-        if (StructureLibAPI.isDebugEnabled()
-                && !channel.toLowerCase(Locale.ROOT).equals(channel))
+        if (StructureLibAPI.isDebugEnabled() && !channel.toLowerCase(Locale.ROOT).equals(channel))
             throw new IllegalArgumentException("Channel name can be lower case ONLY");
         if (data <= 0) throw new IllegalArgumentException();
         if (masterStack.stackTagCompound == null) masterStack.stackTagCompound = new NBTTagCompound();
@@ -131,14 +122,13 @@ public class ChannelDataAccessor {
 
     /**
      * Clear the given subchannel from given trigger item, if it exists
+     * 
      * @param masterStack trigger stack to unset
-     * @param channel channel identifier.
-     *                Note: all channel identifiers are supposed to be lower case and not empty.
+     * @param channel     channel identifier. Note: all channel identifiers are supposed to be lower case and not empty.
      */
     public static void unsetChannelData(ItemStack masterStack, String channel) {
         if (StringUtils.isEmpty(channel) || masterStack == null) throw new IllegalArgumentException();
-        if (StructureLibAPI.isDebugEnabled()
-                && !channel.toLowerCase(Locale.ROOT).equals(channel))
+        if (StructureLibAPI.isDebugEnabled() && !channel.toLowerCase(Locale.ROOT).equals(channel))
             throw new IllegalArgumentException("Channel name can be lower case ONLY");
         if (masterStack.stackTagCompound == null) masterStack.stackTagCompound = new NBTTagCompound();
         NBTTagCompound main = masterStack.stackTagCompound;
@@ -151,6 +141,7 @@ public class ChannelDataAccessor {
 
     /**
      * Wipe all subchannel data on given trigger item
+     * 
      * @param masterStack trigger stack to wipe
      */
     public static void wipeChannelData(ItemStack masterStack) {
@@ -160,10 +151,11 @@ public class ChannelDataAccessor {
 
     /**
      * Iterate over all subchannel data on trigger stack. Does not include master channel!!
+     * 
      * @param masterStack trigger stack to check
      * @return A java8 stream of pairs. Key is channel identifier and value is channel data. Pairs do not support
-     * mutation nor removal. Can still cause {@link java.util.ConcurrentModificationException} if underlying channel
-     * data is modified while stream is working.
+     *         mutation nor removal. Can still cause {@link java.util.ConcurrentModificationException} if underlying
+     *         channel data is modified while stream is working.
      */
     public static Stream<Entry<String, Integer>> iterateChannelData(ItemStack masterStack) {
         if (!hasSubChannel(masterStack)) return Stream.empty();
@@ -173,6 +165,7 @@ public class ChannelDataAccessor {
 
     /**
      * Get the number of subchannels present on given trigger item. Does not include master channel.
+     * 
      * @param masterStack trigger stack to query from
      * @return subchannel count
      */

src/main/java/com/gtnewhorizon/structurelib/alignment/constructable/ConstructableUtility.java

@@ -1,12 +1,7 @@
 package com.gtnewhorizon.structurelib.alignment.constructable;
 
-import com.gtnewhorizon.structurelib.ConfigurationHandler;
-import com.gtnewhorizon.structurelib.StructureLib;
-import com.gtnewhorizon.structurelib.StructureLibAPI;
-import com.gtnewhorizon.structurelib.alignment.IAlignment;
-import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
-import com.gtnewhorizon.structurelib.structure.IItemSource;
 import java.util.WeakHashMap;
+
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.entity.player.EntityPlayerMP;
 import net.minecraft.item.ItemStack;
@@ -16,6 +11,14 @@ import net.minecraft.world.World;
 import net.minecraftforge.common.util.FakePlayer;
 import net.minecraftforge.common.util.ForgeDirection;
 
+import com.gtnewhorizon.structurelib.ConfigurationHandler;
+import com.gtnewhorizon.structurelib.StructureLib;
+import com.gtnewhorizon.structurelib.StructureLibAPI;
+import com.gtnewhorizon.structurelib.alignment.IAlignment;
+import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
+import com.gtnewhorizon.structurelib.structure.IItemSource;
+import com.gtnewhorizon.structurelib.structure.ISurvivalBuildEnvironment;
+
 public class ConstructableUtility {
 
     private static final WeakHashMap<EntityPlayerMP, Long> lastUse = new WeakHashMap<>();
@@ -23,16 +26,16 @@ public class ConstructableUtility {
 
     private ConstructableUtility() {}
 
-    public static boolean handle(
-            ItemStack aStack, EntityPlayer aPlayer, World aWorld, int aX, int aY, int aZ, int aSide) {
+    public static boolean handle(ItemStack aStack, EntityPlayer aPlayer, World aWorld, int aX, int aY, int aZ,
+            int aSide) {
         StructureLibAPI.startHinting(aWorld);
         boolean ret = handle0(aStack, aPlayer, aWorld, aX, aY, aZ, aSide);
         StructureLibAPI.endHinting(aWorld);
         return ret;
     }
 
-    private static boolean handle0(
-            ItemStack aStack, EntityPlayer aPlayer, World aWorld, int aX, int aY, int aZ, int aSide) {
+    private static boolean handle0(ItemStack aStack, EntityPlayer aPlayer, World aWorld, int aX, int aY, int aZ,
+            int aSide) {
         TileEntity tTileEntity = aWorld.getTileEntity(aX, aY, aZ);
         if (tTileEntity == null || aPlayer instanceof FakePlayer) {
             return aPlayer instanceof EntityPlayerMP;
@@ -43,9 +46,10 @@ public class ConstructableUtility {
 
             long timePast = System.currentTimeMillis() - getLastUseMilis(aPlayer);
             if (timePast < ConfigurationHandler.INSTANCE.getAutoPlaceInterval()) {
-                aPlayer.addChatComponentMessage(new ChatComponentTranslation(
-                        "item.structurelib.constructableTrigger.too_fast",
-                        ConfigurationHandler.INSTANCE.getAutoPlaceInterval() - timePast));
+                aPlayer.addChatComponentMessage(
+                        new ChatComponentTranslation(
+                                "item.structurelib.constructableTrigger.too_fast",
+                                ConfigurationHandler.INSTANCE.getAutoPlaceInterval() - timePast));
                 return true;
             }
         } else if (!StructureLib.isCurrentPlayer(aPlayer)) {
@@ -58,8 +62,7 @@ public class ConstructableUtility {
         else if (tTileEntity instanceof IConstructable) {
             constructable = (IConstructable) tTileEntity;
         } else if (IMultiblockInfoContainer.contains(tTileEntity.getClass())) {
-            ExtendedFacing facing = tTileEntity instanceof IAlignment
-                    ? ((IAlignment) tTileEntity).getExtendedFacing()
+            ExtendedFacing facing = tTileEntity instanceof IAlignment ? ((IAlignment) tTileEntity).getExtendedFacing()
                     : ExtendedFacing.of(ForgeDirection.getOrientation(aSide));
             constructable = IMultiblockInfoContainer.<TileEntity>get(tTileEntity.getClass())
                     .toConstructable(tTileEntity, facing);
@@ -74,12 +77,10 @@ public class ConstructableUtility {
             if (aPlayer.capabilities.isCreativeMode) {
                 constructable.construct(aStack, false);
             } else if (constructable instanceof ISurvivalConstructable) {
-                int built = ((ISurvivalConstructable) constructable)
-                        .survivalConstruct(
-                                aStack,
-                                ConfigurationHandler.INSTANCE.getAutoPlaceBudget(),
-                                IItemSource.fromPlayer(playerMP),
-                                playerMP);
+                int built = ((ISurvivalConstructable) constructable).survivalConstruct(
+                        aStack,
+                        ConfigurationHandler.INSTANCE.getAutoPlaceBudget(),
+                        ISurvivalBuildEnvironment.create(IItemSource.fromPlayer(playerMP), playerMP));
                 if (built > 0) {
                     playerMP.addChatMessage(new ChatComponentTranslation("structurelib.autoplace.built_stat", built));
                 } else if (built == -1) {

src/main/java/com/gtnewhorizon/structurelib/alignment/constructable/IConstructable.java

@@ -1,15 +1,26 @@
 package com.gtnewhorizon.structurelib.alignment.constructable;
 
+import net.minecraft.item.ItemStack;
+
+import com.gtnewhorizon.structurelib.structure.IStructureDefinition;
+
 import cpw.mods.fml.relauncher.Side;
 import cpw.mods.fml.relauncher.SideOnly;
-import net.minecraft.item.ItemStack;
 
 /**
  * Created by Tec on 24.03.2017.
  */
 public interface IConstructable {
+
     void construct(ItemStack stackSize, boolean hintsOnly);
 
+    /**
+     * Get the structure definition used for this constructable. Can be null if this constructable is not backed by one.
+     */
+    default IStructureDefinition<?> getStructureDefinition() {
+        return null;
+    }
+
     @SideOnly(Side.CLIENT)
     String[] getStructureDescription(ItemStack stackSize);
 }

src/main/java/com/gtnewhorizon/structurelib/alignment/constructable/IConstructableProvider.java

@@ -6,6 +6,7 @@ import javax.annotation.Nullable;
  * Implement this interface if this tile entity MIGHT be constructable
  */
 public interface IConstructableProvider {
+
     /**
      * @return null if not constructable, an instance otherwise.
      */

src/main/java/com/gtnewhorizon/structurelib/alignment/constructable/IMultiblockInfoContainer.java

@@ -1,19 +1,25 @@
 package com.gtnewhorizon.structurelib.alignment.constructable;
 
-import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
-import com.gtnewhorizon.structurelib.structure.IItemSource;
-import cpw.mods.fml.relauncher.Side;
-import cpw.mods.fml.relauncher.SideOnly;
 import java.util.HashMap;
+
 import net.minecraft.entity.player.EntityPlayerMP;
 import net.minecraft.item.ItemStack;
 import net.minecraft.tileentity.TileEntity;
 import net.minecraft.world.World;
 
+import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
+import com.gtnewhorizon.structurelib.structure.AutoPlaceEnvironment;
+import com.gtnewhorizon.structurelib.structure.IItemSource;
+import com.gtnewhorizon.structurelib.structure.ISurvivalBuildEnvironment;
+
+import cpw.mods.fml.relauncher.Side;
+import cpw.mods.fml.relauncher.SideOnly;
+
 /**
  * To implement IConstructable on not own TileEntities
  */
 public interface IMultiblockInfoContainer<T> {
+
     HashMap<String, IMultiblockInfoContainer<?>> MULTIBLOCK_MAP = new HashMap<>();
 
     /**
@@ -36,28 +42,37 @@ public interface IMultiblockInfoContainer<T> {
     void construct(ItemStack stackSize, boolean hintsOnly, T tileEntity, ExtendedFacing aSide);
 
     /**
-     * Construct the structure using {@link com.gtnewhorizon.structurelib.structure.IStructureElement#survivalPlaceBlock(Object, World, int, int, int, ItemStack, IItemSource, EntityPlayerMP, java.util.function.Consumer)}
+     * Construct the structure using
+     * {@link com.gtnewhorizon.structurelib.structure.IStructureElement#survivalPlaceBlock(Object, World, int, int, int, ItemStack, AutoPlaceEnvironment)}
+     *
      * @return -1 if done, a helping pointer
      */
-    default int survivalConstruct(
-            ItemStack stackSize,
-            int elementBudge,
-            IItemSource source,
-            EntityPlayerMP actorProfile,
-            T tileEntity,
-            ExtendedFacing aSide) {
-        return -1;
-    }
+    int survivalConstruct(ItemStack stackSize, int elementBudge, ISurvivalBuildEnvironment env, T tileEntity,
+            ExtendedFacing aSide);
 
     @SideOnly(Side.CLIENT)
     String[] getDescription(ItemStack stackSize);
 
-    /**
-     * Override this and return {@link #toConstructable(IMultiblockInfoContainer, Object, ExtendedFacing)} if
-     * {@link #survivalConstruct(ItemStack, int, IItemSource, EntityPlayerMP, Object, ExtendedFacing)} isn't a stub
-     */
-    default IConstructable toConstructable(T tileEntity, ExtendedFacing aSide) {
-        return new IConstructable() {
+    default ISurvivalConstructable toConstructable(T tileEntity, ExtendedFacing aSide) {
+        return new ISurvivalConstructable() {
+
+            @Override
+            public int survivalConstruct(ItemStack stackSize, int elementBudget, ISurvivalBuildEnvironment env) {
+                return IMultiblockInfoContainer.this
+                        .survivalConstruct(stackSize, elementBudget, env, tileEntity, aSide);
+            }
+
+            @Override
+            public int survivalConstruct(ItemStack stackSize, int elementBudget, IItemSource source,
+                    EntityPlayerMP actor) {
+                return IMultiblockInfoContainer.this.survivalConstruct(
+                        stackSize,
+                        elementBudget,
+                        ISurvivalBuildEnvironment.create(source, actor),
+                        tileEntity,
+                        aSide);
+            }
+
             @Override
             public void construct(ItemStack stackSize, boolean hintsOnly) {
                 IMultiblockInfoContainer.this.construct(stackSize, hintsOnly, tileEntity, aSide);
@@ -69,25 +84,4 @@ public interface IMultiblockInfoContainer<T> {
             }
         };
     }
-
-    static <T> ISurvivalConstructable toConstructable(
-            IMultiblockInfoContainer<T> thiz, T tileEntity, ExtendedFacing aSide) {
-        return new ISurvivalConstructable() {
-            @Override
-            public int survivalConstruct(
-                    ItemStack stackSize, int elementBudget, IItemSource source, EntityPlayerMP actor) {
-                return thiz.survivalConstruct(stackSize, elementBudget, source, actor, tileEntity, aSide);
-            }
-
-            @Override
-            public void construct(ItemStack stackSize, boolean hintsOnly) {
-                thiz.construct(stackSize, hintsOnly, tileEntity, aSide);
-            }
-
-            @Override
-            public String[] getStructureDescription(ItemStack stackSize) {
-                return thiz.getDescription(stackSize);
-            }
-        };
-    }
 }

src/main/java/com/gtnewhorizon/structurelib/alignment/constructable/ISurvivalConstructable.java

@@ -1,17 +1,85 @@
 package com.gtnewhorizon.structurelib.alignment.constructable;
 
-import com.gtnewhorizon.structurelib.structure.IItemSource;
+import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.entity.player.EntityPlayerMP;
 import net.minecraft.item.ItemStack;
 import net.minecraft.world.World;
 
+import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
+import com.gtnewhorizon.structurelib.structure.AutoPlaceEnvironment;
+import com.gtnewhorizon.structurelib.structure.IItemSource;
+import com.gtnewhorizon.structurelib.structure.ISurvivalBuildEnvironment;
+
+/**
+ * An extension to {@link IConstructable}. Tile Entities (or delegates returned by
+ * {@link IConstructableProvider#getConstructable()} should implement this interface to allow third party tools and
+ * StructureLib builtin constructable tools to trigger autoplace in survival mode.
+ * <p>
+ * While not originally planned, a creative player can also use this interface to trigger autoplace by using an
+ * {@link IItemSource} with every possible items in the game.
+ */
 public interface ISurvivalConstructable extends IConstructable {
+
     /**
-     * Construct the structure using {@link com.gtnewhorizon.structurelib.structure.IStructureElement#survivalPlaceBlock(Object, World, int, int, int, ItemStack, IItemSource, EntityPlayerMP, java.util.function.Consumer)}
+     * End player might want to disable this hack if it turns out to be too crashy
+     */
+    boolean DISABLE_HACKY_MIGRATION_CODE = Boolean.getBoolean("structurelib.disable_isc_migration_hack");
+
+    /**
+     * Construct the structure using
+     * {@link com.gtnewhorizon.structurelib.structure.IStructureElement#survivalPlaceBlock(Object, World, int, int, int, ItemStack, IItemSource, EntityPlayerMP, java.util.function.Consumer)}
+     * or
+     * {@link com.gtnewhorizon.structurelib.structure.IStructureDefinition#survivalBuild(Object, ItemStack, String, World, ExtendedFacing, int, int, int, int, int, int, int, IItemSource, EntityPlayerMP, boolean)}
      *
-     * @param elementBudget The server configured element budget. You can tune this up a bit if the structure is too big, but
-     *                      generally should not be a 4 digits number to not overwhelm the server
+     * @param elementBudget The server configured element budget. The implementor can choose to tune this up a bit if
+     *                      the structure is too big, but generally should not be a 4 digits number to not overwhelm the
+     *                      server
      * @return -1 if done, otherwise number of elements placed this round
      */
-    int survivalConstruct(ItemStack stackSize, int elementBudget, IItemSource source, EntityPlayerMP actor);
+    @Deprecated
+    default int survivalConstruct(ItemStack stackSize, int elementBudget, IItemSource source, EntityPlayerMP actor) {
+        return survivalConstruct(stackSize, elementBudget, ISurvivalBuildEnvironment.create(source, actor));
+    }
+
+    /**
+     * Construct the structure using
+     * {@link com.gtnewhorizon.structurelib.structure.IStructureElement#survivalPlaceBlock(Object, World, int, int, int, ItemStack, AutoPlaceEnvironment)}
+     * or
+     * {@link com.gtnewhorizon.structurelib.structure.IStructureDefinition#survivalBuild(Object, ItemStack, String, World, ExtendedFacing, int, int, int, int, int, int, int, ISurvivalBuildEnvironment, boolean)}
+     *
+     * @param elementBudget The server configured element budget. The implementor can choose to tune this up a bit if
+     *                      the structure is too big, but generally should not be a 4 digits number to not overwhelm the
+     *                      server
+     * @return -1 if done, -2 if not supported (e.g. due to an incompatible change in the API of env, otherwise number
+     *         of elements placed this round
+     */
+    default int survivalConstruct(ItemStack stackSize, int elementBudget, ISurvivalBuildEnvironment env) {
+        EntityPlayer actor = env.getActor();
+        if (actor instanceof EntityPlayerMP)
+            return survivalConstruct(stackSize, elementBudget, env.getSource(), (EntityPlayerMP) actor);
+        else if (!DISABLE_HACKY_MIGRATION_CODE && __get_player() == null) {
+            // as far as I know, no implementor would actually do anything to actor beyond passing it down to
+            // IStructureDefinition, so it's probably fine to proceed like this
+            GlobalStates.entityPlayer.set(env.getActor());
+            try {
+                return survivalConstruct(stackSize, elementBudget, env.getSource(), null);
+            } finally {
+                GlobalStates.entityPlayer.remove();
+            }
+        }
+        return -2;
+    }
+
+    /**
+     * Internal hack. Do not use.
+     */
+    @Deprecated
+    static EntityPlayer __get_player() {
+        return GlobalStates.entityPlayer.get();
+    }
+}
+
+class GlobalStates {
+
+    public static final ThreadLocal<EntityPlayer> entityPlayer = new ThreadLocal<>();
 }

src/main/java/com/gtnewhorizon/structurelib/alignment/enumerable/Direction.java

@@ -1,9 +1,16 @@
 package com.gtnewhorizon.structurelib.alignment.enumerable;
 
-import com.gtnewhorizon.structurelib.util.Vec3Impl;
+import java.util.Arrays;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
 import net.minecraftforge.common.util.ForgeDirection;
 
+import com.gtnewhorizon.structurelib.util.Vec3Impl;
+
 public enum Direction {
+
     DOWN(ForgeDirection.DOWN),
     UP(ForgeDirection.UP),
     NORTH(ForgeDirection.NORTH),
@@ -14,10 +21,12 @@ public enum Direction {
     private final ForgeDirection forgeDirection;
     private final Vec3Impl axisVector;
     public static final Direction[] VALUES = values();
+    private static final Map<Vec3Impl, Direction> reverseMap = Arrays.stream(VALUES)
+            .collect(Collectors.toMap(d -> d.axisVector, Function.identity()));
 
     Direction(ForgeDirection forgeDirection) {
         this.forgeDirection = forgeDirection;
-        axisVector = new Vec3Impl(forgeDirection.offsetX, forgeDirection.offsetY, forgeDirection.offsetZ);
+        axisVector = Vec3Impl.getFromPool(forgeDirection.offsetX, forgeDirection.offsetY, forgeDirection.offsetZ);
     }
 
     public ForgeDirection getForgeDirection() {
@@ -31,4 +40,8 @@ public enum Direction {
     public static Vec3Impl getAxisVector(ForgeDirection forgeDirection) {
         return VALUES[forgeDirection.ordinal()].axisVector;
     }
+
+    public static Direction getByAxisVector(Vec3Impl vec3) {
+        return reverseMap.get(vec3);
+    }
 }

src/main/java/com/gtnewhorizon/structurelib/alignment/enumerable/ExtendedFacing.java

@@ -6,16 +6,19 @@ import static java.lang.Math.abs;
 import static java.util.Arrays.stream;
 import static java.util.stream.Collectors.*;
 
-import com.google.common.collect.ImmutableSet;
-import com.gtnewhorizon.structurelib.alignment.IAlignment;
-import com.gtnewhorizon.structurelib.alignment.IntegerAxisSwap;
-import com.gtnewhorizon.structurelib.util.Vec3Impl;
 import java.util.*;
+
 import net.minecraft.util.StatCollector;
 import net.minecraft.util.Vec3;
 import net.minecraftforge.common.util.ForgeDirection;
 
+import com.google.common.collect.ImmutableSet;
+import com.gtnewhorizon.structurelib.alignment.IAlignment;
+import com.gtnewhorizon.structurelib.alignment.IntegerAxisSwap;
+import com.gtnewhorizon.structurelib.util.Vec3Impl;
+
 public enum ExtendedFacing {
+
     DOWN_NORMAL_NONE("down normal none"),
     DOWN_NORMAL_HORIZONTAL("down normal horizontal"),
     DOWN_NORMAL_VERTICAL("down normal vertical"),
@@ -119,31 +122,31 @@ public enum ExtendedFacing {
     public static final int STATES_COUNT = VALUES.length;
 
     static {
-        stream(values())
-                .forEach(extendedFacing ->
-                        FOR_FACING.compute(extendedFacing.direction, ((forgeDirection, extendedFacings) -> {
-                            if (extendedFacings == null) {
-                                extendedFacings = new ArrayList<>();
-                            }
-                            extendedFacings.add(extendedFacing);
-                            return extendedFacings;
-                        })));
+        stream(values()).forEach(
+                extendedFacing -> FOR_FACING.compute(extendedFacing.direction, ((forgeDirection, extendedFacings) -> {
+                    if (extendedFacings == null) {
+                        extendedFacings = new ArrayList<>();
+                    }
+                    extendedFacings.add(extendedFacing);
+                    return extendedFacings;
+                })));
     }
 
-    private static final Map<String, ExtendedFacing> NAME_LOOKUP =
-            stream(VALUES).collect(toMap(ExtendedFacing::getName2, (extendedFacing) -> extendedFacing));
+    private static final Map<String, ExtendedFacing> NAME_LOOKUP = stream(VALUES)
+            .collect(toMap(ExtendedFacing::getName2, (extendedFacing) -> extendedFacing));
     private static final EnumMap<ForgeDirection, ImmutableSet<ExtendedFacing>> LOOKUP_BY_DIRECTION = stream(VALUES)
-            .collect(groupingBy(
-                    ExtendedFacing::getDirection,
-                    () -> new EnumMap<>(ForgeDirection.class),
-                    collectingAndThen(toSet(), ImmutableSet::copyOf)));
-    private static final EnumMap<Rotation, ImmutableSet<ExtendedFacing>> LOOKUP_BY_ROTATION = stream(VALUES)
-            .collect(groupingBy(
+            .collect(
+                    groupingBy(
+                            ExtendedFacing::getDirection,
+                            () -> new EnumMap<>(ForgeDirection.class),
+                            collectingAndThen(toSet(), ImmutableSet::copyOf)));
+    private static final EnumMap<Rotation, ImmutableSet<ExtendedFacing>> LOOKUP_BY_ROTATION = stream(VALUES).collect(
+            groupingBy(
                     ExtendedFacing::getRotation,
                     () -> new EnumMap<>(Rotation.class),
                     collectingAndThen(toSet(), ImmutableSet::copyOf)));
-    private static final EnumMap<Flip, ImmutableSet<ExtendedFacing>> LOOKUP_BY_FLIP = stream(VALUES)
-            .collect(groupingBy(
+    private static final EnumMap<Flip, ImmutableSet<ExtendedFacing>> LOOKUP_BY_FLIP = stream(VALUES).collect(
+            groupingBy(
                     ExtendedFacing::getFlip,
                     () -> new EnumMap<>(Flip.class),
                     collectingAndThen(toSet(), ImmutableSet::copyOf)));
@@ -333,7 +336,7 @@ public enum ExtendedFacing {
     }
 
     /**
-     * Translates relative to front facing offset  to  world offset
+     * Translates relative to front facing offset to world offset
      *
      * @param abcOffset A,B,C offset (facing relative {@code L-->R,U-->D,F-->B})
      * @return X, Y, Z offset in world
@@ -355,10 +358,32 @@ public enum ExtendedFacing {
     }
 
     /**
-     * Translates world offset  to  relative front facing offset
+     * do note the ABC coordinate system is (X, -Y, Z).
+     */
+    public ForgeDirection getWorldDirection(ForgeDirection abcDirection) {
+        switch (abcDirection) {
+            case NORTH:
+                return getRelativeForwardInWorld();
+            case SOUTH:
+                return getRelativeBackInWorld();
+            case UP:
+                return getRelativeDownInWorld();
+            case DOWN:
+                return getRelativeUpInWorld();
+            case EAST:
+                return getRelativeLeftInWorld();
+            case WEST:
+                return getRelativeRightInWorld();
+            default:
+                return ForgeDirection.UNKNOWN;
+        }
+    }
+
+    /**
+     * Translates world offset to relative front facing offset
      *
      * @param xyzOffset X,Y,Z offset in world
-     * @return A, B, C offset (facing relative  {@code L-->R,U-->D,F-->B})
+     * @return A, B, C offset (facing relative {@code L-->R,U-->D,F-->B})
      */
     public Vec3 getOffsetABC(Vec3 xyzOffset) {
         return integerAxisSwap.translate(xyzOffset);

src/main/java/com/gtnewhorizon/structurelib/alignment/enumerable/Flip.java

@@ -7,9 +7,11 @@ import static java.util.stream.Collectors.toMap;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Random;
+
 import javax.annotation.Nonnull;
 
 public enum Flip {
+
     NONE(3, "none"),
     HORIZONTAL(2, "horizontal"),
     VERTICAL(1, "vertical"),

src/main/java/com/gtnewhorizon/structurelib/alignment/enumerable/Rotation.java

@@ -7,9 +7,11 @@ import static java.util.stream.Collectors.toMap;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Random;
+
 import javax.annotation.Nonnull;
 
 public enum Rotation {
+
     NORMAL(2, "normal"),
     CLOCKWISE(3, "clockwise"),
     UPSIDE_DOWN(0, "upside down"),
@@ -19,8 +21,8 @@ public enum Rotation {
     private final String name;
 
     public static final Rotation[] VALUES = values();
-    private static final Map<String, Rotation> NAME_LOOKUP =
-            stream(VALUES).collect(toMap(Rotation::getName2, (rotation) -> rotation));
+    private static final Map<String, Rotation> NAME_LOOKUP = stream(VALUES)
+            .collect(toMap(Rotation::getName2, (rotation) -> rotation));
 
     Rotation(int oppositeIn, String nameIn) {
         this.opposite = oppositeIn;

src/main/java/com/gtnewhorizon/structurelib/alignment/package-info.java

@@ -1,7 +1,7 @@
 /**
  * This package provide a framework for rotating a given block, or a multiblock structure.
  * <p>
- * All public stuff in this package and its subpackages are considered part of the public API.
- * Backwards compatibility is maintained to the maximum extend possible.
+ * All public stuff in this package and its subpackages are considered part of the public API. Backwards compatibility
+ * is maintained to the maximum extend possible.
  */
 package com.gtnewhorizon.structurelib.alignment;

src/main/java/com/gtnewhorizon/structurelib/block/BlockHint.java

@@ -1,10 +1,7 @@
 package com.gtnewhorizon.structurelib.block;
 
-import com.gtnewhorizon.structurelib.StructureLib;
-import com.gtnewhorizon.structurelib.StructureLibAPI;
-import cpw.mods.fml.relauncher.Side;
-import cpw.mods.fml.relauncher.SideOnly;
 import java.util.List;
+
 import net.minecraft.block.Block;
 import net.minecraft.block.material.Material;
 import net.minecraft.client.renderer.texture.IIconRegister;
@@ -14,7 +11,14 @@ import net.minecraft.item.ItemStack;
 import net.minecraft.util.IIcon;
 import net.minecraft.world.IBlockAccess;
 
+import com.gtnewhorizon.structurelib.StructureLib;
+import com.gtnewhorizon.structurelib.StructureLibAPI;
+
+import cpw.mods.fml.relauncher.Side;
+import cpw.mods.fml.relauncher.SideOnly;
+
 public class BlockHint extends Block {
+
     private static final IIcon[] hint = new IIcon[16];
 
     public BlockHint() {

src/main/java/com/gtnewhorizon/structurelib/command/CommandConfigureChannels.java

@@ -1,10 +1,9 @@
 package com.gtnewhorizon.structurelib.command;
 
-import com.gtnewhorizon.structurelib.alignment.constructable.ChannelDataAccessor;
-import com.gtnewhorizon.structurelib.item.ItemConstructableTrigger;
 import java.util.Arrays;
 import java.util.List;
 import java.util.stream.Collectors;
+
 import net.minecraft.command.CommandBase;
 import net.minecraft.command.ICommandSender;
 import net.minecraft.command.WrongUsageException;
@@ -13,7 +12,11 @@ import net.minecraft.item.ItemStack;
 import net.minecraft.util.ChatComponentText;
 import net.minecraft.util.ChatComponentTranslation;
 
+import com.gtnewhorizon.structurelib.alignment.constructable.ChannelDataAccessor;
+import com.gtnewhorizon.structurelib.item.ItemConstructableTrigger;
+
 public class CommandConfigureChannels extends CommandBase {
+
     @Override
     public String getCommandName() {
         return "sl_channel";
@@ -58,13 +61,12 @@ public class CommandConfigureChannels extends CommandBase {
                 if (!ChannelDataAccessor.hasSubChannel(heldItem)) {
                     sender.addChatMessage(new ChatComponentText("No subchannel"));
                 } else {
-                    sender.addChatMessage(new ChatComponentTranslation(
-                            "item.structurelib.constructableTrigger.desc.lshift.0",
-                            ChannelDataAccessor.countChannelData(heldItem)));
-                    ChannelDataAccessor.iterateChannelData(heldItem)
-                            .map(e -> e.getKey() + ": " + e.getValue())
-                            .map(ChatComponentText::new)
-                            .forEach(player::addChatMessage);
+                    sender.addChatMessage(
+                            new ChatComponentTranslation(
+                                    "item.structurelib.constructableTrigger.desc.lshift.0",
+                                    ChannelDataAccessor.countChannelData(heldItem)));
+                    ChannelDataAccessor.iterateChannelData(heldItem).map(e -> e.getKey() + ": " + e.getValue())
+                            .map(ChatComponentText::new).forEach(player::addChatMessage);
                 }
                 return;
             case "wipe":
@@ -73,13 +75,11 @@ public class CommandConfigureChannels extends CommandBase {
             case "get":
             case "unset":
                 if (args.length < 2) throw new WrongUsageException(getCommandUsage(sender));
-                channel =
-                        args.length == 2 ? args[1] : Arrays.stream(args).skip(1).collect(Collectors.joining());
+                channel = args.length == 2 ? args[1] : Arrays.stream(args).skip(1).collect(Collectors.joining());
                 break;
             case "set":
                 if (args.length < 3) throw new WrongUsageException(getCommandUsage(sender));
-                channel = args.length == 3
-                        ? args[1]
+                channel = args.length == 3 ? args[1]
                         : Arrays.stream(args).skip(1).limit(args.length - 2).collect(Collectors.joining());
                 break;
             default:
@@ -88,9 +88,9 @@ public class CommandConfigureChannels extends CommandBase {
 
         switch (args[0]) {
             case "get":
-                if (ChannelDataAccessor.hasSubChannel(heldItem, channel))
-                    sender.addChatMessage(new ChatComponentText(
-                            channel + " value: " + ChannelDataAccessor.getChannelData(heldItem, channel)));
+                if (ChannelDataAccessor.hasSubChannel(heldItem, channel)) sender.addChatMessage(
+                        new ChatComponentText(
+                                channel + " value: " + ChannelDataAccessor.getChannelData(heldItem, channel)));
                 else sender.addChatMessage(new ChatComponentText(channel + " value: N/A"));
                 break;
             case "clear":

src/main/java/com/gtnewhorizon/structurelib/entity/fx/WeightlessParticleFX.java

@@ -1,20 +1,16 @@
 package com.gtnewhorizon.structurelib.entity.fx;
 
-import cpw.mods.fml.relauncher.Side;
-import cpw.mods.fml.relauncher.SideOnly;
 import net.minecraft.client.particle.EntityFX;
 import net.minecraft.world.World;
 
+import cpw.mods.fml.relauncher.Side;
+import cpw.mods.fml.relauncher.SideOnly;
+
 @SideOnly(Side.CLIENT)
 public class WeightlessParticleFX extends EntityFX {
-    public WeightlessParticleFX(
-            World p_i1205_1_,
-            double p_i1205_2_,
-            double p_i1205_4_,
-            double p_i1205_6_,
-            double p_i1205_8_,
-            double p_i1205_10_,
-            double p_i1205_12_) {
+
+    public WeightlessParticleFX(World p_i1205_1_, double p_i1205_2_, double p_i1205_4_, double p_i1205_6_,
+            double p_i1205_8_, double p_i1205_10_, double p_i1205_12_) {
         super(p_i1205_1_, p_i1205_2_, p_i1205_4_, p_i1205_6_, p_i1205_8_, p_i1205_10_, p_i1205_12_);
         this.motionX = p_i1205_8_ + (double) ((float) (Math.random() * 2.0D - 1.0D) * 0.05F);
         this.motionY = p_i1205_10_ + (double) ((float) (Math.random() * 2.0D - 1.0D) * 0.05F);

src/main/java/com/gtnewhorizon/structurelib/gui/GuiScreenConfigureChannels.java

@@ -1,12 +1,10 @@
 package com.gtnewhorizon.structurelib.gui;
 
-import com.gtnewhorizon.structurelib.StructureLib;
-import com.gtnewhorizon.structurelib.alignment.constructable.ChannelDataAccessor;
-import com.gtnewhorizon.structurelib.gui.GuiScrollableList.IGuiScreen;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map.Entry;
 import java.util.stream.Collectors;
+
 import net.minecraft.client.gui.GuiButton;
 import net.minecraft.client.gui.GuiScreen;
 import net.minecraft.client.gui.GuiTextField;
@@ -15,12 +13,18 @@ import net.minecraft.client.resources.I18n;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.EnumChatFormatting;
 import net.minecraft.util.ResourceLocation;
+
 import org.apache.commons.lang3.StringUtils;
 import org.lwjgl.input.Keyboard;
 import org.lwjgl.input.Mouse;
 import org.lwjgl.opengl.GL11;
 
+import com.gtnewhorizon.structurelib.StructureLib;
+import com.gtnewhorizon.structurelib.alignment.constructable.ChannelDataAccessor;
+import com.gtnewhorizon.structurelib.gui.GuiScrollableList.IGuiScreen;
+
 public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen {
+
     private static final int KEY_MAX_WIDTH = 50;
     private final ItemStack trigger;
     private final GuiChannelsList list;
@@ -48,6 +52,7 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
         guiTop = (this.height - this.getYSize()) / 2;
 
         key = new GuiTextField(fontRendererObj, guiLeft + 45, guiTop + 119, 151 + 12 - 45, 12) {
+
             @Override
             public void writeText(String text) {
                 // force lower case
@@ -58,8 +63,7 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
             @Override
             public void mouseClicked(int p_146192_1_, int p_146192_2_, int p_146192_3_) {
                 super.mouseClicked(p_146192_1_, p_146192_2_, p_146192_3_);
-                boolean flag = p_146192_1_ >= this.xPosition
-                        && p_146192_1_ < this.xPosition + this.width
+                boolean flag = p_146192_1_ >= this.xPosition && p_146192_1_ < this.xPosition + this.width
                         && p_146192_2_ >= this.yPosition
                         && p_146192_2_ < this.yPosition + this.height;
                 if (flag && p_146192_3_ == 1) {
@@ -75,6 +79,7 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
             }
         };
         value = new GuiTextField(fontRendererObj, guiLeft + 45, guiTop + 139, 151 + 12 - 45, 12) {
+
             @Override
             public void writeText(String text) {
                 // ignore write requests containing non digit characters.
@@ -104,8 +109,7 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
             @Override
             public void mouseClicked(int p_146192_1_, int p_146192_2_, int p_146192_3_) {
                 super.mouseClicked(p_146192_1_, p_146192_2_, p_146192_3_);
-                boolean flag = p_146192_1_ >= this.xPosition
-                        && p_146192_1_ < this.xPosition + this.width
+                boolean flag = p_146192_1_ >= this.xPosition && p_146192_1_ < this.xPosition + this.width
                         && p_146192_2_ >= this.yPosition
                         && p_146192_2_ < this.yPosition + this.height;
                 if (flag && p_146192_3_ == 1) {
@@ -122,22 +126,30 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
 
         list.onGuiInit(this);
 
-        addButton(new GuiButton(
-                0, guiLeft + 12, guiTop + 157, 47, 20, I18n.format("item.structurelib.constructableTrigger.gui.add")));
-        addButton(new GuiButton(
-                1,
-                guiLeft + 65,
-                guiTop + 157,
-                47,
-                20,
-                I18n.format("item.structurelib.constructableTrigger.gui.unset")));
-        addButton(new GuiButton(
-                2,
-                guiLeft + 118,
-                guiTop + 157,
-                47,
-                20,
-                I18n.format("item.structurelib.constructableTrigger.gui.wipe")));
+        addButton(
+                new GuiButton(
+                        0,
+                        guiLeft + 12,
+                        guiTop + 157,
+                        47,
+                        20,
+                        I18n.format("item.structurelib.constructableTrigger.gui.add")));
+        addButton(
+                new GuiButton(
+                        1,
+                        guiLeft + 65,
+                        guiTop + 157,
+                        47,
+                        20,
+                        I18n.format("item.structurelib.constructableTrigger.gui.unset")));
+        addButton(
+                new GuiButton(
+                        2,
+                        guiLeft + 118,
+                        guiTop + 157,
+                        47,
+                        20,
+                        I18n.format("item.structurelib.constructableTrigger.gui.wipe")));
 
         updateButtons();
     }
@@ -236,9 +248,9 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
     private void updateButtons() {
         // this will be called from setText of key and value. NEVER UPDATE THE VALUE OF THESE HERE OR GET A
         // STACKOVERFLOW!
-        boolean existing = ChannelDataAccessor.hasSubChannel(trigger, key.getText());
-        getButtonList().get(0).displayString = existing
-                ? I18n.format("item.structurelib.constructableTrigger.gui.set")
+        String keyText = key.getText();
+        boolean existing = !StringUtils.isEmpty(keyText) && ChannelDataAccessor.hasSubChannel(trigger, keyText);
+        getButtonList().get(0).displayString = existing ? I18n.format("item.structurelib.constructableTrigger.gui.set")
                 : I18n.format("item.structurelib.constructableTrigger.gui.add");
         getButtonList().get(0).enabled = !StringUtils.isBlank(value.getText());
         getButtonList().get(1).enabled = existing && !StringUtils.isBlank(value.getText());
@@ -299,14 +311,21 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
         super.drawScreen(mX, mY, partialTick);
         list.drawScreen(mX, mY, partialTick);
         fontRendererObj.drawString(
-                I18n.format("item.structurelib.constructableTrigger.gui.key"), guiLeft + 12, guiTop + 122, 0);
+                I18n.format("item.structurelib.constructableTrigger.gui.key"),
+                guiLeft + 12,
+                guiTop + 122,
+                0);
         key.drawTextBox();
         fontRendererObj.drawString(
-                I18n.format("item.structurelib.constructableTrigger.gui.value"), guiLeft + 12, guiTop + 142, 0);
+                I18n.format("item.structurelib.constructableTrigger.gui.value"),
+                guiLeft + 12,
+                guiTop + 142,
+                0);
         value.drawTextBox();
     }
 
     private class GuiChannelsList extends GuiScrollableList<Entry<String, Integer>> {
+
         private List<Entry<String, Integer>> cache;
 
         public GuiChannelsList(int width, int height, int originX, int originY, int slotHeight) {
@@ -315,11 +334,7 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
 
         @Override
         public Entry<String, Integer> getElementAt(int index) {
-            return ChannelDataAccessor.iterateChannelData(trigger)
-                    .sorted()
-                    .skip(index)
-                    .findFirst()
-                    .orElse(null);
+            return ChannelDataAccessor.iterateChannelData(trigger).sorted().skip(index).findFirst().orElse(null);
         }
 
         @Override
@@ -329,8 +344,7 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
 
         @Override
         protected boolean elementClicked(int elementIndex, boolean doubleClick, int mXRelative, int mYRelative) {
-            if (mXRelative >= margin + 1
-                    && mXRelative <= margin + 5
+            if (mXRelative >= margin + 1 && mXRelative <= margin + 5
                     && mYRelative >= margin / 2 + 1
                     && mYRelative <= margin / 2 + 5) {
                 Entry<String, Integer> e = getElementAt(elementIndex);
@@ -348,8 +362,8 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
         }
 
         @Override
-        protected void drawElement(
-                int elementIndex, int x, int y, int height, Tessellator tessellator, boolean isHovering) {
+        protected void drawElement(int elementIndex, int x, int y, int height, Tessellator tessellator,
+                boolean isHovering) {
             if (elementIndex < 0 || elementIndex >= cache.size()) {
                 return;
             }
@@ -381,8 +395,7 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
             // TODO optimize this to not create a billion string, or maybe cache this
             String s = fontRendererObj.trimStringToWidth(e, keyMaxWidth);
             if (s.length() != e.length()) {
-                StringBuilder buffer =
-                        new StringBuilder(s).deleteCharAt(s.length() - 1).append("...");
+                StringBuilder buffer = new StringBuilder(s).deleteCharAt(s.length() - 1).append("...");
                 while ((s = fontRendererObj.trimStringToWidth(buffer.toString(), keyMaxWidth)).length()
                         != buffer.length())
                     // drop last original char
@@ -390,9 +403,7 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
                 do {
                     buffer.append('.');
                 } while (fontRendererObj.getStringWidth(buffer.toString()) <= keyMaxWidth);
-                s = buffer.deleteCharAt(s.length() - 1)
-                        .insert(s.length() - 3, EnumChatFormatting.GRAY)
-                        .toString();
+                s = buffer.deleteCharAt(s.length() - 1).insert(s.length() - 3, EnumChatFormatting.GRAY).toString();
             }
             return s;
         }

src/main/java/com/gtnewhorizon/structurelib/gui/GuiScrollableList.java

@@ -2,37 +2,40 @@ package com.gtnewhorizon.structurelib.gui;
 
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
+
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.GuiButton;
 import net.minecraft.client.gui.ScaledResolution;
 import net.minecraft.client.renderer.Tessellator;
+
 import org.lwjgl.input.Mouse;
 import org.lwjgl.opengl.GL11;
 
 /**
  * Shamelessly stolen from EnderCore, with some amount of edit to fit in one file. Original code from CrazyPants.
  * <p>
- * As the code has been released into public domain, it is now LGPL as part of this library as a whole.
- * You can go to EnderCore's repository to obtain a public domain copy though
+ * As the code has been released into public domain, it is now LGPL as part of this library as a whole. You can go to
+ * EnderCore's repository to obtain a public domain copy though
  *
  * Major edits
  * <ul>
- *     <li>Separate dwheel handling to handleDWheel. The next event calls often cause the mouse click event to
- *     not fire on other widgets</li>
- *     <li>scrollbar are now rendered within width</li>
- *     <li>added prepareDrawElements</li>
+ * <li>Separate dwheel handling to handleDWheel. The next event calls often cause the mouse click event to not fire on
+ * other widgets</li>
+ * <li>scrollbar are now rendered within width</li>
+ * <li>added prepareDrawElements</li>
  * </ul>
  *
  * @author CrazyPants
  * @author glee8e
  */
 public abstract class GuiScrollableList<T> {
+
     protected final int slotHeight;
     private final Minecraft mc = Minecraft.getMinecraft();
-    protected int originX;
-    protected int originY;
-    protected int width;
-    protected int height;
+    protected final int originX;
+    protected final int originY;
+    protected final int width;
+    protected final int height;
     protected int minY;
     protected int maxY;
     protected int minX;
@@ -41,7 +44,7 @@ public abstract class GuiScrollableList<T> {
     protected int mouseY;
     protected int selectedIndex = -1;
     protected int margin = 4;
-    protected List<ListSelectionListener<T>> listeners = new CopyOnWriteArrayList<>();
+    protected final List<ListSelectionListener<T>> listeners = new CopyOnWriteArrayList<>();
     private int scrollUpButtonID;
     private int scrollDownButtonID;
     private float initialClickY = -2.0F;
@@ -113,8 +116,8 @@ public abstract class GuiScrollableList<T> {
 
     public abstract int getNumElements();
 
-    protected abstract void drawElement(
-            int elementIndex, int x, int y, int height, Tessellator tessellator, boolean isHovering);
+    protected abstract void drawElement(int elementIndex, int x, int y, int height, Tessellator tessellator,
+            boolean isHovering);
 
     protected boolean elementClicked(int elementIndex, boolean doubleClick, int mXRelative, int mYRelative) {
         return true;
@@ -153,11 +156,11 @@ public abstract class GuiScrollableList<T> {
     public void actionPerformed(GuiButton b) {
         if (b.enabled) {
             if (b.id == scrollUpButtonID) {
-                amountScrolled -= slotHeight * 2 / 3;
+                amountScrolled -= slotHeight * 2f / 3;
                 initialClickY = -2.0F;
                 clampScrollToBounds();
             } else if (b.id == scrollDownButtonID) {
-                amountScrolled += slotHeight * 2 / 3;
+                amountScrolled += slotHeight * 2f / 3;
                 initialClickY = -2.0F;
                 clampScrollToBounds();
             }
@@ -165,8 +168,7 @@ public abstract class GuiScrollableList<T> {
     }
 
     /**
-     * draws the slot to the screen, pass in mouse's current x and y and partial
-     * ticks
+     * draws the slot to the screen, pass in mouse's current x and y and partial ticks
      */
     public void drawScreen(int mX, int mY, float partialTick) {
         this.mouseX = mX;
@@ -325,9 +327,9 @@ public abstract class GuiScrollableList<T> {
     public void handleDWheel(int mouseWheelDelta) {
         if (!Mouse.isButtonDown(0)) {
             if (mouseWheelDelta > 0) {
-                amountScrolled -= slotHeight / 2;
+                amountScrolled -= slotHeight / 2f;
             } else /* if (mouseWheelDelta < 0) */ {
-                amountScrolled += slotHeight / 2;
+                amountScrolled += slotHeight / 2f;
             }
         }
     }
@@ -343,15 +345,17 @@ public abstract class GuiScrollableList<T> {
                 int y = mouseY - minY + (int) amountScrolled - margin;
                 int mouseOverElement = y / slotHeight;
 
-                if (mouseX >= minX
-                        && mouseX <= maxX
+                if (mouseX >= minX && mouseX <= maxX
                         && mouseOverElement >= 0
                         && y >= 0
                         && mouseOverElement < getNumElements()) {
-                    boolean doubleClick =
-                            mouseOverElement == selectedIndex && Minecraft.getSystemTime() - lastClickedTime < 250L;
+                    boolean doubleClick = mouseOverElement == selectedIndex
+                            && Minecraft.getSystemTime() - lastClickedTime < 250L;
                     if (elementClicked(
-                            mouseOverElement, doubleClick, mouseX - minX, y - slotHeight * mouseOverElement)) {
+                            mouseOverElement,
+                            doubleClick,
+                            mouseX - minX,
+                            y - slotHeight * mouseOverElement)) {
                         setSelection(mouseOverElement);
                         lastClickedTime = Minecraft.getSystemTime();
                     }

src/main/java/com/gtnewhorizon/structurelib/item/ItemBlockHint.java

@@ -3,6 +3,7 @@ package com.gtnewhorizon.structurelib.item;
 import static net.minecraft.util.StatCollector.translateToLocal;
 
 import java.util.List;
+
 import net.minecraft.block.Block;
 import net.minecraft.creativetab.CreativeTabs;
 import net.minecraft.entity.player.EntityPlayer;
@@ -11,6 +12,7 @@ import net.minecraft.item.ItemStack;
 import net.minecraft.util.EnumChatFormatting;
 
 public class ItemBlockHint extends ItemBlock {
+
     public ItemBlockHint(Block p_i45328_1_) {
         super(p_i45328_1_);
         setMaxDamage(0);
@@ -35,33 +37,35 @@ public class ItemBlockHint extends ItemBlock {
             case 9:
             case 10:
             case 11:
-                aList.add(EnumChatFormatting.AQUA.toString()
-                        + EnumChatFormatting.BOLD
-                        + translateToLocal("structurelib.blockhint.desc.1")); // Placeholder for a certain group.
+                aList.add(
+                        EnumChatFormatting.AQUA.toString() + EnumChatFormatting.BOLD
+                                + translateToLocal("structurelib.blockhint.desc.1")); // Placeholder for a certain
+                                                                                      // group.
                 break;
             case 12:
-                aList.add(EnumChatFormatting.AQUA.toString()
-                        + EnumChatFormatting.BOLD
-                        + translateToLocal("structurelib.blockhint.desc.2")); // General placeholder.
+                aList.add(
+                        EnumChatFormatting.AQUA.toString() + EnumChatFormatting.BOLD
+                                + translateToLocal("structurelib.blockhint.desc.2")); // General placeholder.
                 break;
             case 13:
-                aList.add(EnumChatFormatting.AQUA.toString()
-                        + EnumChatFormatting.BOLD
-                        + translateToLocal("structurelib.blockhint.desc.3")); // Make sure it contains Air material.
+                aList.add(
+                        EnumChatFormatting.AQUA.toString() + EnumChatFormatting.BOLD
+                                + translateToLocal("structurelib.blockhint.desc.3")); // Make sure it contains Air
+                                                                                      // material.
                 break;
             case 14:
-                aList.add(EnumChatFormatting.AQUA.toString()
-                        + EnumChatFormatting.BOLD
-                        + translateToLocal(
-                                "structurelib.blockhint.desc.4")); // Make sure it does not contain Air material.
+                aList.add(
+                        EnumChatFormatting.AQUA.toString() + EnumChatFormatting.BOLD
+                                + translateToLocal("structurelib.blockhint.desc.4")); // Make sure it does not contain
+                                                                                      // Air material.
                 break;
             case 15:
-                aList.add(EnumChatFormatting.BLUE.toString()
-                        + translateToLocal("structurelib.blockhint.desc.5")); // ERROR, what did u expect?
+                aList.add(EnumChatFormatting.BLUE + translateToLocal("structurelib.blockhint.desc.5")); // ERROR, what
+                                                                                                        // did u expect?
                 break;
             default: // WTF?
                 aList.add("Damn son where did you get that!?");
-                aList.add(EnumChatFormatting.BLUE.toString() + "From outer space... I guess...");
+                aList.add(EnumChatFormatting.BLUE + "From outer space... I guess...");
         }
     }
 

src/main/java/com/gtnewhorizon/structurelib/item/ItemConstructableTrigger.java

@@ -5,17 +5,21 @@ import static net.minecraft.util.EnumChatFormatting.BLUE;
 import static net.minecraft.util.StatCollector.translateToLocal;
 import static net.minecraft.util.StatCollector.translateToLocalFormatted;
 
-import com.gtnewhorizon.structurelib.StructureLib;
-import com.gtnewhorizon.structurelib.alignment.constructable.ChannelDataAccessor;
-import com.gtnewhorizon.structurelib.alignment.constructable.ConstructableUtility;
 import java.util.List;
+
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
 import net.minecraft.world.World;
+
 import org.lwjgl.input.Keyboard;
 
+import com.gtnewhorizon.structurelib.StructureLib;
+import com.gtnewhorizon.structurelib.alignment.constructable.ChannelDataAccessor;
+import com.gtnewhorizon.structurelib.alignment.constructable.ConstructableUtility;
+
 public class ItemConstructableTrigger extends Item {
+
     public ItemConstructableTrigger() {
         setUnlocalizedName("structurelib.constructableTrigger");
         setTextureName(MOD_ID + ":itemConstructableTrigger");
@@ -30,17 +34,8 @@ public class ItemConstructableTrigger extends Item {
     }
 
     @Override
-    public boolean onItemUseFirst(
-            ItemStack stack,
-            EntityPlayer player,
-            World world,
-            int x,
-            int y,
-            int z,
-            int side,
-            float hitX,
-            float hitY,
-            float hitZ) {
+    public boolean onItemUseFirst(ItemStack stack, EntityPlayer player, World world, int x, int y, int z, int side,
+            float hitX, float hitY, float hitZ) {
         return ConstructableUtility.handle(stack, player, world, x, y, z, side);
     }
 
@@ -48,27 +43,25 @@ public class ItemConstructableTrigger extends Item {
     @Override
     public void addInformation(ItemStack aStack, EntityPlayer ep, List aList, boolean boo) {
         if (Keyboard.isKeyDown(Keyboard.KEY_LSHIFT)) {
-            aList.add(translateToLocalFormatted(
-                    "item.structurelib.constructableTrigger.desc.lshift.0",
-                    ChannelDataAccessor.countChannelData(aStack)));
-            ChannelDataAccessor.iterateChannelData(aStack)
-                    .map(e -> e.getKey() + ": " + e.getValue())
+            aList.add(
+                    translateToLocalFormatted(
+                            "item.structurelib.constructableTrigger.desc.lshift.0",
+                            ChannelDataAccessor.countChannelData(aStack)));
+            ChannelDataAccessor.iterateChannelData(aStack).map(e -> e.getKey() + ": " + e.getValue())
                     .forEach(aList::add);
         } else {
-            aList.add(translateToLocal(
-                    "item.structurelib.constructableTrigger.desc.0")); // Triggers Constructable Interface
-            aList.add(BLUE
-                    + translateToLocal(
-                            "item.structurelib.constructableTrigger.desc.1")); // Shows multiblock construction details,
-            aList.add(BLUE
-                    + translateToLocal(
-                            "item.structurelib.constructableTrigger.desc.2")); // just Use on a multiblock controller.
-            aList.add(BLUE
-                    + translateToLocal(
-                            "item.structurelib.constructableTrigger.desc.3")); // (Sneak Use in creative to build)
-            aList.add(BLUE
-                    + translateToLocal(
-                            "item.structurelib.constructableTrigger.desc.4")); // Quantity affects tier/mode/type
+            aList.add(translateToLocal("item.structurelib.constructableTrigger.desc.0")); // Triggers Constructable
+                                                                                          // Interface
+            aList.add(BLUE + translateToLocal("item.structurelib.constructableTrigger.desc.1")); // Shows multiblock
+                                                                                                 // construction
+                                                                                                 // details,
+            aList.add(BLUE + translateToLocal("item.structurelib.constructableTrigger.desc.2")); // just Use on a
+                                                                                                 // multiblock
+                                                                                                 // controller.
+            aList.add(BLUE + translateToLocal("item.structurelib.constructableTrigger.desc.3")); // (Sneak Use in
+                                                                                                 // creative to build)
+            aList.add(BLUE + translateToLocal("item.structurelib.constructableTrigger.desc.4")); // Quantity affects
+                                                                                                 // tier/mode/type
             if (ChannelDataAccessor.hasSubChannel(aStack))
                 aList.add(translateToLocal("item.structurelib.constructableTrigger.desc.5"));
         }

src/main/java/com/gtnewhorizon/structurelib/item/ItemFrontRotationTool.java

@@ -3,18 +3,22 @@ package com.gtnewhorizon.structurelib.item;
 import static com.gtnewhorizon.structurelib.StructureLibAPI.MOD_ID;
 import static net.minecraft.util.StatCollector.translateToLocal;
 
-import com.gtnewhorizon.structurelib.StructureLib;
-import com.gtnewhorizon.structurelib.alignment.AlignmentUtility;
-import cpw.mods.fml.relauncher.Side;
-import cpw.mods.fml.relauncher.SideOnly;
 import java.util.List;
+
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.EnumChatFormatting;
 import net.minecraft.world.World;
 
+import com.gtnewhorizon.structurelib.StructureLib;
+import com.gtnewhorizon.structurelib.alignment.AlignmentUtility;
+
+import cpw.mods.fml.relauncher.Side;
+import cpw.mods.fml.relauncher.SideOnly;
+
 public class ItemFrontRotationTool extends Item {
+
     public ItemFrontRotationTool() {
         setMaxStackSize(1);
         setUnlocalizedName("structurelib.frontRotationTool");
@@ -23,17 +27,8 @@ public class ItemFrontRotationTool extends Item {
     }
 
     @Override
-    public boolean onItemUseFirst(
-            ItemStack stack,
-            EntityPlayer player,
-            World world,
-            int x,
-            int y,
-            int z,
-            int side,
-            float hitX,
-            float hitY,
-            float hitZ) {
+    public boolean onItemUseFirst(ItemStack stack, EntityPlayer player, World world, int x, int y, int z, int side,
+            float hitX, float hitY, float hitZ) {
         return AlignmentUtility.handle(player, world, x, y, z);
     }
 
@@ -41,9 +36,13 @@ public class ItemFrontRotationTool extends Item {
     @SideOnly(Side.CLIENT)
     public void addInformation(ItemStack p_77624_1_, EntityPlayer p_77624_2_, List aList, boolean p_77624_4_) {
         aList.add(translateToLocal("item.structurelib.frontRotationTool.desc.0")); // Triggers Front Rotation Interface
-        aList.add(EnumChatFormatting.BLUE
-                + translateToLocal("item.structurelib.frontRotationTool.desc.1")); // Rotates only the front panel,
-        aList.add(EnumChatFormatting.BLUE
-                + translateToLocal("item.structurelib.frontRotationTool.desc.2")); // which allows structure rotation.
+        aList.add(EnumChatFormatting.BLUE + translateToLocal("item.structurelib.frontRotationTool.desc.1")); // Rotates
+                                                                                                             // only the
+                                                                                                             // front
+                                                                                                             // panel,
+        aList.add(EnumChatFormatting.BLUE + translateToLocal("item.structurelib.frontRotationTool.desc.2")); // which
+                                                                                                             // allows
+                                                                                                             // structure
+                                                                                                             // rotation.
     }
 }

src/main/java/com/gtnewhorizon/structurelib/net/AlignmentMessage.java

@@ -1,20 +1,23 @@
 package com.gtnewhorizon.structurelib.net;
 
-import com.gtnewhorizon.structurelib.StructureLib;
-import com.gtnewhorizon.structurelib.alignment.IAlignment;
-import com.gtnewhorizon.structurelib.alignment.IAlignmentProvider;
-import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
-import cpw.mods.fml.common.network.ByteBufUtils;
-import cpw.mods.fml.common.network.simpleimpl.IMessage;
-import cpw.mods.fml.common.network.simpleimpl.IMessageHandler;
-import cpw.mods.fml.common.network.simpleimpl.MessageContext;
-import io.netty.buffer.ByteBuf;
 import net.minecraft.nbt.NBTTagCompound;
 import net.minecraft.tileentity.TileEntity;
 import net.minecraft.world.World;
 import net.minecraftforge.common.DimensionManager;
 
+import com.gtnewhorizon.structurelib.StructureLib;
+import com.gtnewhorizon.structurelib.alignment.IAlignment;
+import com.gtnewhorizon.structurelib.alignment.IAlignmentProvider;
+import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
+
+import cpw.mods.fml.common.network.ByteBufUtils;
+import cpw.mods.fml.common.network.simpleimpl.IMessage;
+import cpw.mods.fml.common.network.simpleimpl.IMessageHandler;
+import cpw.mods.fml.common.network.simpleimpl.MessageContext;
+import io.netty.buffer.ByteBuf;
+
 public abstract class AlignmentMessage implements IMessage {
+
     int mPosX;
     int mPosY;
     int mPosZ;
@@ -45,10 +48,6 @@ public abstract class AlignmentMessage implements IMessage {
         ByteBufUtils.writeTag(pBuffer, tFXTag);
     }
 
-    /**
-     * {@link com.gtnewhorizon.structurelib.structure.IStructureDefinition#check(Object, String, World, ExtendedFacing, int, int, int, int, int, int, boolean)}
-     * @param provider
-     */
     private AlignmentMessage(IAlignmentProvider provider) {
         if (!(provider instanceof TileEntity)) throw new IllegalArgumentException("Provider must be a TileEntity");
         IAlignment alignment = provider.getAlignment();
@@ -70,6 +69,7 @@ public abstract class AlignmentMessage implements IMessage {
     }
 
     public static class AlignmentQuery extends AlignmentMessage {
+
         public AlignmentQuery() {}
 
         public AlignmentQuery(IAlignmentProvider provider) {
@@ -82,6 +82,7 @@ public abstract class AlignmentMessage implements IMessage {
     }
 
     public static class AlignmentData extends AlignmentMessage {
+
         public AlignmentData() {}
 
         private AlignmentData(AlignmentQuery query) {
@@ -102,11 +103,11 @@ public abstract class AlignmentMessage implements IMessage {
     }
 
     public static class ClientHandler implements IMessageHandler<AlignmentData, IMessage> {
+
         @Override
         public IMessage onMessage(AlignmentData pMessage, MessageContext pCtx) {
             if (StructureLib.getCurrentPlayer().worldObj.provider.dimensionId == pMessage.mPosD) {
-                TileEntity te = StructureLib.getCurrentPlayer()
-                        .worldObj
+                TileEntity te = StructureLib.getCurrentPlayer().worldObj
                         .getTileEntity(pMessage.mPosX, pMessage.mPosY, pMessage.mPosZ);
                 if (te instanceof IAlignmentProvider) {
                     IAlignment alignment = ((IAlignmentProvider) te).getAlignment();
@@ -120,6 +121,7 @@ public abstract class AlignmentMessage implements IMessage {
     }
 
     public static class ServerHandler implements IMessageHandler<AlignmentQuery, AlignmentData> {
+
         @Override
         public AlignmentData onMessage(AlignmentQuery pMessage, MessageContext pCtx) {
             World world = DimensionManager.getWorld(pMessage.mPosD);

src/main/java/com/gtnewhorizon/structurelib/net/ErrorHintParticleMessage.java

@@ -4,12 +4,14 @@ import static com.gtnewhorizon.structurelib.StructureLib.LOGGER;
 
 import com.gtnewhorizon.structurelib.StructureLib;
 import com.gtnewhorizon.structurelib.StructureLibAPI;
+
 import cpw.mods.fml.common.network.simpleimpl.IMessage;
 import cpw.mods.fml.common.network.simpleimpl.IMessageHandler;
 import cpw.mods.fml.common.network.simpleimpl.MessageContext;
 import io.netty.buffer.ByteBuf;
 
 public class ErrorHintParticleMessage implements IMessage {
+
     private int x;
     private short y;
     private int z;
@@ -37,17 +39,21 @@ public class ErrorHintParticleMessage implements IMessage {
     }
 
     public static class Handler implements IMessageHandler<ErrorHintParticleMessage, IMessage> {
+
         @Override
         public IMessage onMessage(ErrorHintParticleMessage msg, MessageContext ctx) {
             boolean updateResult = StructureLibAPI.markHintParticleError(
-                    StructureLib.getCurrentPlayer(), StructureLib.getCurrentPlayer().worldObj, msg.x, msg.y, msg.z);
-            if (StructureLibAPI.isDebugEnabled())
-                LOGGER.debug(
-                        "Server instructed to mark hint particle at ({}, {}, {}) error, result {}!",
-                        msg.x,
-                        msg.y,
-                        msg.z,
-                        updateResult);
+                    StructureLib.getCurrentPlayer(),
+                    StructureLib.getCurrentPlayer().worldObj,
+                    msg.x,
+                    msg.y,
+                    msg.z);
+            if (StructureLibAPI.isDebugEnabled()) LOGGER.debug(
+                    "Server instructed to mark hint particle at ({}, {}, {}) error, result {}!",
+                    msg.x,
+                    msg.y,
+                    msg.z,
+                    updateResult);
             return null;
         }
     }

src/main/java/com/gtnewhorizon/structurelib/net/SetChannelDataMessage.java

@@ -1,23 +1,28 @@
 package com.gtnewhorizon.structurelib.net;
 
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import net.minecraft.entity.player.EntityPlayerMP;
+import net.minecraft.item.ItemStack;
+
+import org.apache.commons.lang3.tuple.Pair;
+
 import com.gtnewhorizon.structurelib.StructureLib;
 import com.gtnewhorizon.structurelib.alignment.constructable.ChannelDataAccessor;
 import com.gtnewhorizon.structurelib.item.ItemConstructableTrigger;
+
 import cpw.mods.fml.common.network.ByteBufUtils;
 import cpw.mods.fml.common.network.simpleimpl.IMessage;
 import cpw.mods.fml.common.network.simpleimpl.IMessageHandler;
 import cpw.mods.fml.common.network.simpleimpl.MessageContext;
 import io.netty.buffer.ByteBuf;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Map;
-import java.util.Map.Entry;
-import net.minecraft.entity.player.EntityPlayerMP;
-import net.minecraft.item.ItemStack;
-import org.apache.commons.lang3.tuple.Pair;
 
 public class SetChannelDataMessage implements IMessage {
-    private List<Map.Entry<String, Integer>> data = new ArrayList<>();
+
+    private final List<Map.Entry<String, Integer>> data = new ArrayList<>();
 
     public SetChannelDataMessage() {}
 
@@ -44,6 +49,7 @@ public class SetChannelDataMessage implements IMessage {
     }
 
     public static class Handler implements IMessageHandler<SetChannelDataMessage, IMessage> {
+
         @Override
         public IMessage onMessage(SetChannelDataMessage message, MessageContext ctx) {
             EntityPlayerMP player = ctx.getServerHandler().playerEntity;

src/main/java/com/gtnewhorizon/structurelib/net/UpdateHintParticleMessage.java

@@ -4,12 +4,14 @@ import static com.gtnewhorizon.structurelib.StructureLib.LOGGER;
 
 import com.gtnewhorizon.structurelib.StructureLib;
 import com.gtnewhorizon.structurelib.StructureLibAPI;
+
 import cpw.mods.fml.common.network.simpleimpl.IMessage;
 import cpw.mods.fml.common.network.simpleimpl.IMessageHandler;
 import cpw.mods.fml.common.network.simpleimpl.MessageContext;
 import io.netty.buffer.ByteBuf;
 
 public class UpdateHintParticleMessage implements IMessage {
+
     private int x;
     private short y;
     private int z;
@@ -53,6 +55,7 @@ public class UpdateHintParticleMessage implements IMessage {
     }
 
     public static class Handler implements IMessageHandler<UpdateHintParticleMessage, IMessage> {
+
         @Override
         public IMessage onMessage(UpdateHintParticleMessage msg, MessageContext ctx) {
             boolean updateResult = StructureLibAPI.updateHintParticleTint(
@@ -61,16 +64,13 @@ public class UpdateHintParticleMessage implements IMessage {
                     msg.x,
                     msg.y,
                     msg.z,
-                    new short[] {
-                        msg.r, msg.g, msg.b, msg.a,
-                    });
-            if (StructureLibAPI.isDebugEnabled())
-                LOGGER.debug(
-                        "Server instructed to update hint particle at ({}, {}, {}), result {}!",
-                        msg.x,
-                        msg.y,
-                        msg.z,
-                        updateResult);
+                    new short[] { msg.r, msg.g, msg.b, msg.a, });
+            if (StructureLibAPI.isDebugEnabled()) LOGGER.debug(
+                    "Server instructed to update hint particle at ({}, {}, {}), result {}!",
+                    msg.x,
+                    msg.y,
+                    msg.z,
+                    updateResult);
             return null;
         }
     }

src/main/java/com/gtnewhorizon/structurelib/structure/AutoPlaceEnvironment.java

@@ -0,0 +1,231 @@
+package com.gtnewhorizon.structurelib.structure;
+
+import java.util.Map;
+import java.util.function.Consumer;
+import java.util.function.Predicate;
+
+import javax.annotation.Nonnull;
+
+import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.entity.player.EntityPlayerMP;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.IChatComponent;
+
+import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
+
+/**
+ * Represent the environment in which autoplace of a single element took place.
+ */
+public class AutoPlaceEnvironment {
+
+    private IItemSource source;
+    private final EntityPlayer actor;
+    private final Consumer<IChatComponent> chatter;
+    private final IStructureDefinition<?> definition;
+    private final String piece;
+    private final ExtendedFacing facing;
+    final int[] offsetABC;
+    private final int[] baseOffsetABC;
+
+    public static AutoPlaceEnvironment fromLegacy(IItemSource source, EntityPlayer actor,
+            Consumer<IChatComponent> chatter) {
+        if (source instanceof WrappedIItemSource) {
+            AutoPlaceEnvironment original = ((WrappedIItemSource) source).container;
+            // feels like this is extremely likely to cause issues, but this does allow us to recover lost info.
+            // TODO probably should remove this once all addons migrate over
+            if (actor != original.actor || chatter != original.chatter) {
+                AutoPlaceEnvironment newEnv = original;
+                if (actor != original.actor) newEnv = newEnv.withActor(actor);
+                if (chatter != original.chatter) newEnv = newEnv.withChatter(chatter);
+                return newEnv;
+            }
+            return original;
+        }
+        return new AutoPlaceEnvironment(source, actor, chatter, null, null, null, null, null);
+    }
+
+    AutoPlaceEnvironment(EntityPlayer actor, Consumer<IChatComponent> chatter, IStructureDefinition<?> definition,
+            String piece, ExtendedFacing facing, int[] baseOffsetABC) {
+        this.source = null;
+        this.actor = actor;
+        this.chatter = chatter;
+        this.definition = definition;
+        this.piece = piece;
+        this.facing = facing;
+        this.offsetABC = new int[3];
+        this.baseOffsetABC = baseOffsetABC;
+    }
+
+    AutoPlaceEnvironment(IItemSource source, EntityPlayer actor, Consumer<IChatComponent> chatter,
+            IStructureDefinition<?> definition, String piece, ExtendedFacing facing, int[] offsetABC,
+            int[] baseOffsetABC) {
+        this.source = definition != null && !(source instanceof WrappedIItemSource)
+                ? new WrappedIItemSource(this, source)
+                : source;
+        this.actor = actor;
+        this.chatter = chatter;
+        this.definition = definition;
+        this.piece = piece;
+        this.facing = facing;
+        this.offsetABC = offsetABC;
+        this.baseOffsetABC = baseOffsetABC;
+    }
+
+    protected AutoPlaceEnvironment(AutoPlaceEnvironment parent) {
+        this(
+                parent.getSource(),
+                parent.getActor(),
+                parent.getChatter(),
+                parent.definition,
+                parent.piece,
+                parent.facing,
+                parent.offsetABC,
+                parent.baseOffsetABC);
+    }
+
+    void setSource(IItemSource source) {
+        this.source = definition != null && !(source instanceof WrappedIItemSource)
+                ? new WrappedIItemSource(this, source)
+                : source;
+    }
+
+    public APILevel getAPILevel() {
+        return definition == null ? actor instanceof EntityPlayerMP ? APILevel.Legacy : APILevel.LegacyRelaxed
+                : APILevel.V2;
+    }
+
+    /**
+     * From where survival autoplace will drain resources.
+     */
+    public IItemSource getSource() {
+        return source;
+    }
+
+    /**
+     * The initiator of actions. for very critical errors you can also just send the error messages here, bypassing any
+     * filter that {@link #getChatter()} might have. You might want to use
+     * {@link com.gtnewhorizon.structurelib.StructureLibAPI#addThrottledChat(Object, EntityPlayer, IChatComponent, short)}
+     * to help reduce spam.
+     */
+    public EntityPlayer getActor() {
+        return actor;
+    }
+
+    /**
+     * send error messages here. Caller will choose an appropriate way to forward it to player if the other fallbacks
+     * also fails.
+     */
+    public Consumer<IChatComponent> getChatter() {
+        return chatter;
+    }
+
+    /**
+     * Test if given location is contained within the current piece.
+     *
+     * @param offsetA offset in A direction <b>relative to current element</b>
+     * @param offsetB offset in B direction <b>relative to current element</b>
+     * @param offsetC offset in C direction <b>relative to current element</b>
+     * @return true if contained, false otherwise.
+     */
+    public boolean isContainedInPiece(int offsetA, int offsetB, int offsetC) {
+        if (definition == null) return false;
+        return definition.isContainedInStructure(
+                piece,
+                offsetABC[0] + offsetA + baseOffsetABC[0],
+                offsetABC[1] + offsetB + baseOffsetABC[1],
+                offsetABC[2] + offsetC + baseOffsetABC[2]);
+    }
+
+    public ExtendedFacing getFacing() {
+        return facing;
+    }
+
+    /**
+     * Return a new instance with source modified to given value.
+     *
+     * @param source new source
+     * @return new instance
+     */
+    public AutoPlaceEnvironment withSource(IItemSource source) {
+        return new AutoPlaceEnvironment(source, actor, chatter, definition, piece, facing, offsetABC, baseOffsetABC);
+    }
+
+    /**
+     * Return a new instance with actor modified to given value.
+     *
+     * @param actor new actor
+     * @return new instance
+     */
+    public AutoPlaceEnvironment withActor(EntityPlayer actor) {
+        return new AutoPlaceEnvironment(source, actor, chatter, definition, piece, facing, offsetABC, baseOffsetABC);
+    }
+
+    /**
+     * Return a new instance with chatter modified to given value.
+     *
+     * @param chatter new chatter
+     * @return new instance
+     */
+    public AutoPlaceEnvironment withChatter(Consumer<IChatComponent> chatter) {
+        return new AutoPlaceEnvironment(source, actor, chatter, definition, piece, facing, offsetABC, baseOffsetABC);
+    }
+
+    private static class WrappedIItemSource implements IItemSource {
+
+        final AutoPlaceEnvironment container;
+        final IItemSource delegate;
+
+        public WrappedIItemSource(AutoPlaceEnvironment container, IItemSource delegate) {
+            this.container = container;
+            this.delegate = delegate;
+        }
+
+        @Override
+        @Nonnull
+        public Map<ItemStack, Integer> take(Predicate<ItemStack> predicate, boolean simulate, int count) {
+            return delegate.take(predicate, simulate, count);
+        }
+
+        @Override
+        public ItemStack takeOne(Predicate<ItemStack> predicate, boolean simulate) {
+            return delegate.takeOne(predicate, simulate);
+        }
+
+        @Override
+        public boolean takeAll(Predicate<ItemStack> predicate, boolean simulate, int count) {
+            return delegate.takeAll(predicate, simulate, count);
+        }
+
+        @Override
+        public boolean takeOne(ItemStack stack, boolean simulate) {
+            return delegate.takeOne(stack, simulate);
+        }
+
+        @Override
+        public boolean takeAll(ItemStack stack, boolean simulate) {
+            return delegate.takeAll(stack, simulate);
+        }
+    }
+
+    /**
+     * Defines the various API level an {@link AutoPlaceEnvironment} has implemented.
+     * <p>
+     * Enum constants are defined in chronological order.
+     */
+    public enum APILevel {
+        /**
+         * Implements {@link #getChatter()}, {@link #getActor()} and {@link #getSource()}. {@link #getActor()} is
+         * guaranteed to be an {@link net.minecraft.entity.player.EntityPlayerMP}
+         */
+        Legacy,
+        /**
+         * Implements {@link #getChatter()}, {@link #getActor()} and {@link #getSource()}. {@link #getActor()} is
+         * <b>NOT</b> guaranteed to be an {@link net.minecraft.entity.player.EntityPlayerMP}
+         */
+        LegacyRelaxed,
+        /**
+         * Implements everything so far we have defined.
+         */
+        V2,
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/structure/ChatThrottleKey.java

@@ -3,6 +3,7 @@ package com.gtnewhorizon.structurelib.structure;
 class ChatThrottleKey {
 
     static class NoExplicitChannel {
+
         private static final int hashOffset = NoExplicitChannel.class.hashCode();
         private final String subchannel;
 

src/main/java/com/gtnewhorizon/structurelib/structure/DefaultSurvivalBuildEnvironment.java

@@ -0,0 +1,24 @@
+package com.gtnewhorizon.structurelib.structure;
+
+import net.minecraft.entity.player.EntityPlayer;
+
+class DefaultSurvivalBuildEnvironment implements ISurvivalBuildEnvironment {
+
+    private final IItemSource source;
+    private final EntityPlayer actor;
+
+    public DefaultSurvivalBuildEnvironment(IItemSource source, EntityPlayer actor) {
+        this.source = source;
+        this.actor = actor;
+    }
+
+    @Override
+    public IItemSource getSource() {
+        return source;
+    }
+
+    @Override
+    public EntityPlayer getActor() {
+        return actor;
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/structure/IBlockPosConsumer.java

@@ -3,5 +3,6 @@ package com.gtnewhorizon.structurelib.structure;
 import net.minecraft.world.World;
 
 public interface IBlockPosConsumer {
+
     void consume(World world, int x, int y, int z);
 }

src/main/java/com/gtnewhorizon/structurelib/structure/ICustomBlockSetting.java

@@ -4,9 +4,10 @@ import net.minecraft.block.Block;
 import net.minecraft.world.World;
 
 public interface ICustomBlockSetting {
+
     /**
-     * Default block setting calls {@link World#setBlock(int x, int y, int z, Block block, int meta, int updateType)} like:
-     * {@code world.setBlock(x,y,z,this/block,meta,2)} where updateType 2 means to update lighting and stuff
+     * Default block setting calls {@link World#setBlock(int x, int y, int z, Block block, int meta, int updateType)}
+     * like: {@code world.setBlock(x,y,z,this/block,meta,2)} where updateType 2 means to update lighting and stuff
      *
      * @param world world that should be affected
      * @param x     x position to set

src/main/java/com/gtnewhorizon/structurelib/structure/IItemSource.java

@@ -1,29 +1,61 @@
 package com.gtnewhorizon.structurelib.structure;
 
+import java.util.Map;
+import java.util.function.Predicate;
+
+import javax.annotation.Nonnull;
+
+import net.minecraft.entity.player.EntityPlayerMP;
+import net.minecraft.inventory.IInventory;
+import net.minecraft.item.ItemStack;
+
 import com.gtnewhorizon.structurelib.util.InventoryIterable;
 import com.gtnewhorizon.structurelib.util.InventoryUtility;
 import com.gtnewhorizon.structurelib.util.ItemStackPredicate;
 import com.gtnewhorizon.structurelib.util.ItemStackPredicate.NBTMode;
-import java.util.Map;
-import java.util.function.Predicate;
-import javax.annotation.Nonnull;
-import net.minecraft.entity.player.EntityPlayerMP;
-import net.minecraft.inventory.IInventory;
-import net.minecraft.item.ItemStack;
 
+/**
+ * Represent an item source. Take only, cannot be placed back.
+ */
 public interface IItemSource {
+
     /**
-     * We are probably not going to need to get a lot of items from this method
-     * so I don't care about the overhead of storing all fetched items even if downstream code doesn't need it
+     * Retrieve some amount of items from this item source matching given filter.
+     * <p>
+     * We probably don't need to get a lot of items from this method, so I don't care about the overhead of storing all
+     * fetched items even if downstream code doesn't need it
+     *
+     * @param predicate filtering predicate. should return true for ItemStacks that should be added to result collection
+     * @param simulate  whether to actually commit the modification. true for dry run, false otherwise.
+     * @param count     how many items to extract.
+     * @return A nonnull map reflecting the result of extraction. Note this map is NBT and metadata aware.
      */
     @Nonnull
     Map<ItemStack, Integer> take(Predicate<ItemStack> predicate, boolean simulate, int count);
 
+    /**
+     * Take exactly one item that matches the predicate.
+     *
+     * @param predicate filtering predicate. should return true for ItemStacks that should be added to result collection
+     * @param simulate  whether to actually commit the modification. true for dry run, false otherwise.
+     * @return item stack, or null if none matches
+     * @throws IllegalArgumentException if given predicate is null.
+     */
     default ItemStack takeOne(Predicate<ItemStack> predicate, boolean simulate) {
+        if (predicate == null) throw new IllegalArgumentException();
         Map<ItemStack, Integer> take = take(predicate, simulate, 1);
         return take.isEmpty() ? null : take.keySet().iterator().next();
     }
 
+    /**
+     * Take exactly count amount of items matching predicate.
+     *
+     * @param predicate filtering predicate. should return true for ItemStacks that should be added to result collection
+     * @param simulate  whether to actually commit the modification. true for dry run, false otherwise.
+     * @param count     how many items to extract.
+     * @return true if at least count amount of items can be/is taken.
+     * @throws IllegalArgumentException if given predicate is null
+     */
     default boolean takeAll(Predicate<ItemStack> predicate, boolean simulate, int count) {
         // fast path for 1 item take requests
         if (count == 1) return takeOne(predicate, simulate) != null;
@@ -33,24 +65,56 @@ public interface IItemSource {
         return true;
     }
 
+    /**
+     * Take exactly one item. ItemStack given must have a stack size of 1.
+     * <p>
+     * This is meant to be an optimized version of {@link #takeOne(Predicate, boolean)}. Implementations that support
+     * item storage indexed by ItemStack can use this to speed up calculation.
+     *
+     * @param stack    what item to extract. The NBT tag of this ItemStack is siginifcant and will be considered during
+     *                 matching. must have a stack size of 1.
+     * @param simulate whether to actually commit the modification. true for dry run, false otherwise.
+     * @return true if found. false otherwise
+     * @throws IllegalArgumentException if given stack is invalid, or has a stack size other than 1.
+     */
     default boolean takeOne(ItemStack stack, boolean simulate) {
         if (stack == null || stack.getItem() == null || stack.stackSize != 1) throw new IllegalArgumentException();
         ItemStack took = takeOne(ItemStackPredicate.from(stack, NBTMode.EXACT), simulate);
-        return took == null || took.stackSize <= 0;
+        return took != null && took.stackSize > 0;
     }
 
+    /**
+     * Take some item. Will not take item if it cannot find enough items to take.
+     * <p>
+     * This is meant to be an optimized version of {@link #takeOne(Predicate, boolean)}. Implementations that support
+     * indexing off ItemStack can use this to speed up calculation.
+     *
+     * @param stack    what item and how many to extract. The NBT tag of this ItemStack is siginifcant and will be
+     *                 considered during matching
+     * @param simulate whether to actually commit the modification. true for dry run, false otherwise.
+     * @return true if enough item can be/has been extracted. false otherwise
+     * @throws IllegalArgumentException if given stack is invalid
+     */
     default boolean takeAll(ItemStack stack, boolean simulate) {
+        if (stack == null || stack.getItem() == null) throw new IllegalArgumentException();
         // fast path for 1 item take requests
         if (stack.stackSize == 1) return takeOne(stack, simulate);
         ItemStackPredicate predicate = ItemStackPredicate.from(stack, NBTMode.EXACT);
         Map<ItemStack, Integer> have = take(predicate, true, stack.stackSize);
         if (have.values().stream().mapToInt(Integer::intValue).sum() < stack.stackSize) return false;
-        take(predicate, simulate, stack.stackSize);
+        if (simulate) return true;
+        take(predicate, false, stack.stackSize);
         return true;
     }
 
+    /**
+     * Construct an IItemSource from inventories associated with given player.
+     * <p>
+     * This will be backed by {@link InventoryUtility}
+     */
     static IItemSource fromPlayer(EntityPlayerMP player) {
         return new IItemSource() {
+
             @Nonnull
             @Override
             public Map<ItemStack, Integer> take(Predicate<ItemStack> p, boolean s, int c) {
@@ -71,6 +135,11 @@ public interface IItemSource {
         };
     }
 
+    /**
+     * Construct an IItemSource from given inventory
+     * <p>
+     * This will be backed by {@link InventoryUtility}
+     */
     static IItemSource fromInventory(IInventory inv) {
         return (p, s, c) -> InventoryUtility.takeFromInventory(new InventoryIterable<>(inv), p, s, c, true);
     }

src/main/java/com/gtnewhorizon/structurelib/structure/ISpecialItemBlock.java

@@ -3,5 +3,6 @@ package com.gtnewhorizon.structurelib.structure;
 import net.minecraft.block.Block;
 
 public interface ISpecialItemBlock {
+
     int getItemMetaFromBlockMeta(Block block, int blockMeta);
 }

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureDefinition.java

@@ -3,24 +3,28 @@ package com.gtnewhorizon.structurelib.structure;
 import static com.gtnewhorizon.structurelib.structure.IStructureWalker.ignoreBlockUnloaded;
 import static com.gtnewhorizon.structurelib.structure.IStructureWalker.skipBlockUnloaded;
 
-import com.gtnewhorizon.structurelib.StructureLib;
-import com.gtnewhorizon.structurelib.StructureLibAPI;
-import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
 import java.util.function.Function;
+
+import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.entity.player.EntityPlayerMP;
 import net.minecraft.item.ItemStack;
 import net.minecraft.world.World;
 
+import com.gtnewhorizon.structurelib.StructureLib;
+import com.gtnewhorizon.structurelib.StructureLibAPI;
+import com.gtnewhorizon.structurelib.alignment.constructable.ISurvivalConstructable;
+import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
+
 /**
  * This is the structure definition of your multi. You will have one of these for each multi.
  *
  * <h2>Cache the instances of this class</h2>
  * <p>
- * You will construct this definition once per multi, either at class load or at first call to your variant of {@code getStructureDefinition()}.
- * You can use a {@link ClassValue ClassValue&lt;IStructureDefinition&lt;?>>} if you have a template for subclass.
- * You can also use {@link StructureUtility#defer(Function) defer()} or its overloads for simpler cases, but it is
- * slightly less performant as it will allocate new objects on each structure check, whereas {@link ClassValue} will
- * allocate once and cache it onwards.
+ * You will construct this definition once per multi, either at class load or at first call to your variant of
+ * {@code getStructureDefinition()}. You can use a {@link ClassValue ClassValue&lt;IStructureDefinition&lt;?>>} if you
+ * have a template for subclass. You can also use {@link StructureUtility#defer(Function) defer()} or its overloads for
+ * simpler cases, but it is slightly less performant as it will allocate new objects on each structure check, whereas
+ * {@link ClassValue} will allocate once and cache it onwards.
  * <p>
  * <h2>Constructing</h2>
  * <p>
@@ -28,59 +32,62 @@ import net.minecraft.world.World;
  * <p>
  * Builder has two main methods:
  * <ul>
- * <li>{@link com.gtnewhorizon.structurelib.structure.StructureDefinition.Builder#addShape(String, String[][]) addShape()}
- * is a 2d string array describing the layout of structure. You can optionally use `StructureUtility#transpose()`
- * to transpose the array to make the structure look nicer in source code.
- * <li>{@link com.gtnewhorizon.structurelib.structure.StructureDefinition.Builder#addElement(Character, IStructureElement) addElement()}. It takes a char identifier (mapped to a char in any of {@link com.gtnewhorizon.structurelib.structure.StructureDefinition.Builder#addShape(String, String[][]) addShape()} calls) and a {@link IStructureElement}.
+ * <li>{@link com.gtnewhorizon.structurelib.structure.StructureDefinition.Builder#addShape(String, String[][])
+ * addShape()} is a 2d string array describing the layout of structure. You can optionally use
+ * `StructureUtility#transpose()` to transpose the array to make the structure look nicer in source code.
+ * <li>{@link com.gtnewhorizon.structurelib.structure.StructureDefinition.Builder#addElement(Character, IStructureElement)
+ * addElement()}. It takes a char identifier (mapped to a char in any of
+ * {@link com.gtnewhorizon.structurelib.structure.StructureDefinition.Builder#addShape(String, String[][]) addShape()}
+ * calls) and a {@link IStructureElement}.
  * </ul>
  * <h2>Position A, B and C</h2>
  *
  * Imagine you stand in front of the controller, with controller facing towards you not rotated or flipped.
  * <ul>
- * <li>The "A" position would be the number of blocks on the left side of the controller, not counting controller itself.</li>
- * <li>The "B" position would be the number of blocks on the top side of the controller, not counting controller itself.</li>
+ * <li>The "A" position would be the number of blocks on the left side of the controller, not counting controller
+ * itself.</li>
+ * <li>The "B" position would be the number of blocks on the top side of the controller, not counting controller
+ * itself.</li>
  * <li>The "C" position would be the number of blocks between you and controller, not counting controller itself.</li>
  * </ul>
+ * 
  * @param <T> Type of the context object. Usually this will be the multiblock controller.
  */
 public interface IStructureDefinition<T> {
+
     /**
      * Used internally
      * <p>
-     * Might, but is not required, to throw {@link java.util.NoSuchElementException} if the given structure piece is not found.
+     * Might, but is not required, to throw {@link java.util.NoSuchElementException} if the given structure piece is not
+     * found.
      *
      * @param name same name as for other methods here
      * @return the array of elements to process
-     * @throws java.util.NoSuchElementException if the given structure piece is not found and the moon phase perfectly matches
+     * @throws java.util.NoSuchElementException if the given structure piece is not found and the moon phase perfectly
+     *                                          matches
      */
     IStructureElement<T>[] getStructureFor(String name);
 
+    boolean isContainedInStructure(String name, int offsetA, int offsetB, int offsetC);
+
     /**
      * Run a structure check.
-     * @param object context object. usually multiblock controller.
-     * @param piece the structure piece's string identifier.
-     * @param world the world object this check takes place in.
-     * @param extendedFacing the current structure's orientation.
-     * @param basePositionX X location of the structure
-     * @param basePositionY Y location of the structure
-     * @param basePositionZ Z location of the structure
-     * @param basePositionA see class javadoc
-     * @param basePositionB see class javadoc
-     * @param basePositionC see class javadoc
+     * 
+     * @param object              context object. usually multiblock controller.
+     * @param piece               the structure piece's string identifier.
+     * @param world               the world object this check takes place in.
+     * @param extendedFacing      the current structure's orientation.
+     * @param basePositionX       X location of the structure
+     * @param basePositionY       Y location of the structure
+     * @param basePositionZ       Z location of the structure
+     * @param basePositionA       see class javadoc
+     * @param basePositionB       see class javadoc
+     * @param basePositionC       see class javadoc
      * @param forceCheckAllBlocks check all location even if chunk not currently loaded.
      * @return true if successful, false otherwise
      */
-    default boolean check(
-            T object,
-            String piece,
-            World world,
-            ExtendedFacing extendedFacing,
-            int basePositionX,
-            int basePositionY,
-            int basePositionZ,
-            int basePositionA,
-            int basePositionB,
-            int basePositionC,
+    default boolean check(T object, String piece, World world, ExtendedFacing extendedFacing, int basePositionX,
+            int basePositionY, int basePositionZ, int basePositionA, int basePositionB, int basePositionC,
             boolean forceCheckAllBlocks) {
         return iterate(
                 object,
@@ -100,29 +107,21 @@ public interface IStructureDefinition<T> {
 
     /**
      * Spawn hint particles. Should not be called on server side.
-     * @param object context object. usually multiblock controller.
-     * @param piece the structure piece's string identifier.
-     * @param world the world object this check takes place in.
+     * 
+     * @param object         context object. usually multiblock controller.
+     * @param piece          the structure piece's string identifier.
+     * @param world          the world object this check takes place in.
      * @param extendedFacing the current structure's orientation.
-     * @param basePositionX X location of the structure
-     * @param basePositionY Y location of the structure
-     * @param basePositionZ Z location of the structure
-     * @param basePositionA see class javadoc
-     * @param basePositionB see class javadoc
-     * @param basePositionC see class javadoc
+     * @param basePositionX  X location of the structure
+     * @param basePositionY  Y location of the structure
+     * @param basePositionZ  Z location of the structure
+     * @param basePositionA  see class javadoc
+     * @param basePositionB  see class javadoc
+     * @param basePositionC  see class javadoc
      * @return true if successful, false otherwise
      */
-    default boolean hints(
-            T object,
-            ItemStack trigger,
-            String piece,
-            World world,
-            ExtendedFacing extendedFacing,
-            int basePositionX,
-            int basePositionY,
-            int basePositionZ,
-            int basePositionA,
-            int basePositionB,
+    default boolean hints(T object, ItemStack trigger, String piece, World world, ExtendedFacing extendedFacing,
+            int basePositionX, int basePositionY, int basePositionZ, int basePositionA, int basePositionB,
             int basePositionC) {
         return iterate(
                 object,
@@ -141,33 +140,24 @@ public interface IStructureDefinition<T> {
     }
 
     /**
-     * Build the multi in creative mode on a best effort basis. Does not guarantee the structure is correct after a
+     * Build the multi in creative mode on a best-effort basis. Does not guarantee the structure is correct after a
      * successful call.
      *
-     * @param object context object. usually multiblock controller.
-     * @param trigger The trigger item that contains channel data.
-     * @param piece the structure piece's string identifier.
-     * @param world the world object this check takes place in.
+     * @param object         context object. usually multiblock controller.
+     * @param trigger        The trigger item that contains channel data.
+     * @param piece          the structure piece's string identifier.
+     * @param world          the world object this check takes place in.
      * @param extendedFacing the current structure's orientation.
-     * @param basePositionX X location of the structure
-     * @param basePositionY Y location of the structure
-     * @param basePositionZ Z location of the structure
-     * @param basePositionA see class javadoc
-     * @param basePositionB see class javadoc
-     * @param basePositionC see class javadoc
+     * @param basePositionX  X location of the structure
+     * @param basePositionY  Y location of the structure
+     * @param basePositionZ  Z location of the structure
+     * @param basePositionA  see class javadoc
+     * @param basePositionB  see class javadoc
+     * @param basePositionC  see class javadoc
      * @return true if sucessful, false otherwise
      */
-    default boolean build(
-            T object,
-            ItemStack trigger,
-            String piece,
-            World world,
-            ExtendedFacing extendedFacing,
-            int basePositionX,
-            int basePositionY,
-            int basePositionZ,
-            int basePositionA,
-            int basePositionB,
+    default boolean build(T object, ItemStack trigger, String piece, World world, ExtendedFacing extendedFacing,
+            int basePositionX, int basePositionY, int basePositionZ, int basePositionA, int basePositionB,
             int basePositionC) {
         return iterate(
                 object,
@@ -186,38 +176,29 @@ public interface IStructureDefinition<T> {
     }
 
     /**
-     * Call {@link #build(Object, ItemStack, String, World, ExtendedFacing, int, int, int, int, int, int)} if {@code hintsOnly},
-     * call {@link #hints(Object, ItemStack, String, World, ExtendedFacing, int, int, int, int, int, int)} otherwise.
+     * Call {@link #build(Object, ItemStack, String, World, ExtendedFacing, int, int, int, int, int, int)} if
+     * {@code hintsOnly}, call
+     * {@link #hints(Object, ItemStack, String, World, ExtendedFacing, int, int, int, int, int, int)} otherwise.
      *
-     * @param object context object. usually multiblock controller.
-     * @param trigger The trigger item that contains channel data.
-     * @param piece the structure piece's string identifier.
-     * @param world the world object this check takes place in.
+     * @param object         context object. usually multiblock controller.
+     * @param trigger        The trigger item that contains channel data.
+     * @param piece          the structure piece's string identifier.
+     * @param world          the world object this check takes place in.
      * @param extendedFacing the current structure's orientation.
-     * @param basePositionX X location of the structure
-     * @param basePositionY Y location of the structure
-     * @param basePositionZ Z location of the structure
-     * @param basePositionA see class javadoc
-     * @param basePositionB see class javadoc
-     * @param basePositionC see class javadoc
-     * @param hintsOnly whether to spawn hints or do creative build.
+     * @param basePositionX  X location of the structure
+     * @param basePositionY  Y location of the structure
+     * @param basePositionZ  Z location of the structure
+     * @param basePositionA  see class javadoc
+     * @param basePositionB  see class javadoc
+     * @param basePositionC  see class javadoc
+     * @param hintsOnly      whether to spawn hints or do creative build.
      * @return true if sucessful, false otherwise
      * @see #hints(Object, ItemStack, String, World, ExtendedFacing, int, int, int, int, int, int)
      * @see #build(Object, ItemStack, String, World, ExtendedFacing, int, int, int, int, int, int)
      */
-    default boolean buildOrHints(
-            T object,
-            ItemStack trigger,
-            String piece,
-            World world,
-            ExtendedFacing extendedFacing,
-            int basePositionX,
-            int basePositionY,
-            int basePositionZ,
-            int basePositionA,
-            int basePositionB,
-            int basePositionC,
-            boolean hintsOnly) {
+    default boolean buildOrHints(T object, ItemStack trigger, String piece, World world, ExtendedFacing extendedFacing,
+            int basePositionX, int basePositionY, int basePositionZ, int basePositionA, int basePositionB,
+            int basePositionC, boolean hintsOnly) {
         return iterate(
                 object,
                 trigger,
@@ -237,45 +218,91 @@ public interface IStructureDefinition<T> {
     /**
      * Cause a survival build.
      *
-     * @param object context object. usually multiblock controller.
-     * @param trigger The trigger item that contains channel data.
-     * @param piece the structure piece's string identifier.
-     * @param world the world object this check takes place in.
+     * @param object         context object. usually multiblock controller.
+     * @param trigger        The trigger item that contains channel data.
+     * @param piece          the structure piece's string identifier.
+     * @param world          the world object this check takes place in.
      * @param extendedFacing the current structure's orientation.
-     * @param basePositionX X location of the structure
-     * @param basePositionY Y location of the structure
-     * @param basePositionZ Z location of the structure
-     * @param basePositionA see class javadoc
-     * @param basePositionB see class javadoc
-     * @param basePositionC see class javadoc
-     * @param elementBudget build up to this many elements
-     * @param source        from where to drain resource
-     * @param actor         source of action
-     * @param check         whether {@link IStructureElement#check(Object, World, int, int, int)} should be called if anything
-     *                      would be placed. use with caution.
-     *                      if in doubt, call {@link #check(Object, String, World, ExtendedFacing, int, int, int, int, int, int, boolean)}
-     *                      after this call and set this parameter to false
+     * @param basePositionX  X location of the structure
+     * @param basePositionY  Y location of the structure
+     * @param basePositionZ  Z location of the structure
+     * @param basePositionA  see class javadoc
+     * @param basePositionB  see class javadoc
+     * @param basePositionC  see class javadoc
+     * @param elementBudget  build up to this many elements
+     * @param source         from where to drain resource
+     * @param actor          source of action
+     * @param check          whether {@link IStructureElement#check(Object, World, int, int, int)} should be called if
+     *                       anything would be placed. use with caution. if in doubt, call
+     *                       {@link #check(Object, String, World, ExtendedFacing, int, int, int, int, int, int, boolean)}
+     *                       after this call and set this parameter to false
      * @return number of elements built, or -1 if structure done
      * @see #build(Object, ItemStack, String, World, ExtendedFacing, int, int, int, int, int, int)
      */
-    default int survivalBuild(
-            T object,
-            ItemStack trigger,
-            String piece,
-            World world,
-            ExtendedFacing extendedFacing,
-            int basePositionX,
-            int basePositionY,
-            int basePositionZ,
-            int basePositionA,
-            int basePositionB,
-            int basePositionC,
-            int elementBudget,
-            IItemSource source,
-            EntityPlayerMP actor,
-            boolean check) {
-        SurvivalBuildStructureWalker<T> walker =
-                new SurvivalBuildStructureWalker<>(object, trigger, source, actor, elementBudget, check);
+    @Deprecated
+    default int survivalBuild(T object, ItemStack trigger, String piece, World world, ExtendedFacing extendedFacing,
+            int basePositionX, int basePositionY, int basePositionZ, int basePositionA, int basePositionB,
+            int basePositionC, int elementBudget, IItemSource source, EntityPlayerMP actor, boolean check) {
+        EntityPlayer realActor;
+        if (actor == null) {
+            realActor = ISurvivalConstructable.__get_player();
+            if (realActor == null) throw new IllegalArgumentException();
+        } else {
+            realActor = actor;
+        }
+        return survivalBuild(
+                object,
+                trigger,
+                piece,
+                world,
+                extendedFacing,
+                basePositionX,
+                basePositionY,
+                basePositionZ,
+                basePositionA,
+                basePositionB,
+                basePositionC,
+                elementBudget,
+                ISurvivalBuildEnvironment.create(source, realActor),
+                check);
+    }
+
+    /**
+     * Cause a survival build.
+     *
+     * @param object         context object. usually multiblock controller.
+     * @param trigger        The trigger item that contains channel data.
+     * @param piece          the structure piece's string identifier.
+     * @param world          the world object this check takes place in.
+     * @param extendedFacing the current structure's orientation.
+     * @param basePositionX  X location of the structure
+     * @param basePositionY  Y location of the structure
+     * @param basePositionZ  Z location of the structure
+     * @param basePositionA  see class javadoc
+     * @param basePositionB  see class javadoc
+     * @param basePositionC  see class javadoc
+     * @param elementBudget  build up to this many elements
+     * @param env            build environment.
+     * @param check          whether {@link IStructureElement#check(Object, World, int, int, int)} should be called if
+     *                       anything would be placed. use with caution. if in doubt, call
+     *                       {@link IStructureDefinition#check(Object, String, World, ExtendedFacing, int, int, int, int, int, int, boolean)}
+     *                       after this call and set this parameter to false
+     * @return number of elements built, or -1 if structure done
+     * @see #build(Object, ItemStack, String, World, ExtendedFacing, int, int, int, int, int, int)
+     */
+    default int survivalBuild(T object, ItemStack trigger, String piece, World world, ExtendedFacing extendedFacing,
+            int basePositionX, int basePositionY, int basePositionZ, int basePositionA, int basePositionB,
+            int basePositionC, int elementBudget, ISurvivalBuildEnvironment env, boolean check) {
+        SurvivalBuildStructureWalker<T> walker = new SurvivalBuildStructureWalker<>(
+                object,
+                trigger,
+                elementBudget,
+                env,
+                this,
+                piece,
+                extendedFacing,
+                new int[] { basePositionA, basePositionB, basePositionC },
+                check);
         StructureUtility.iterateV2(
                 getStructureFor(piece),
                 world,
@@ -293,38 +320,29 @@ public interface IStructureDefinition<T> {
 
     /**
      * Low level utility.
-     * @param object context object. usually multiblock controller.
-     * @param trigger The trigger item that contains channel data.
-     * @param elements the structure piece
-     * @param world the world object this check takes place in.
-     * @param extendedFacing the current structure's orientation.
-     * @param basePositionX X location of the structure
-     * @param basePositionY Y location of the structure
-     * @param basePositionZ Z location of the structure
-     * @param basePositionA see class javadoc
-     * @param basePositionB see class javadoc
-     * @param basePositionC see class javadoc
-     * @param hintsOnly whether to spawn hints or do creative build. no effect if {@code checkBlocksIfNotNullForceCheckAllIfTrue} is not null.
-     * @param checkBlocksIfNotNullForceCheckAllIfTrue creative build or spawn hints if null. Force check not loaded chunk
-     *                                                if true. Check only loaded chunk is false.
+     * 
+     * @param object                                  context object. usually multiblock controller.
+     * @param trigger                                 The trigger item that contains channel data.
+     * @param elements                                the structure piece
+     * @param world                                   the world object this check takes place in.
+     * @param extendedFacing                          the current structure's orientation.
+     * @param basePositionX                           X location of the structure
+     * @param basePositionY                           Y location of the structure
+     * @param basePositionZ                           Z location of the structure
+     * @param basePositionA                           see class javadoc
+     * @param basePositionB                           see class javadoc
+     * @param basePositionC                           see class javadoc
+     * @param hintsOnly                               whether to spawn hints or do creative build. no effect if
+     *                                                {@code checkBlocksIfNotNullForceCheckAllIfTrue} is not null.
+     * @param checkBlocksIfNotNullForceCheckAllIfTrue creative build or spawn hints if null. Force check not loaded
+     *                                                chunk if true. Check only loaded chunk is false.
      * @return true if iteration completed successfully.
      * @param <T> type of context object.
      */
-    static <T> boolean iterate(
-            T object,
-            ItemStack trigger,
-            IStructureElement<T>[] elements,
-            World world,
-            ExtendedFacing extendedFacing,
-            int basePositionX,
-            int basePositionY,
-            int basePositionZ,
-            int basePositionA,
-            int basePositionB,
-            int basePositionC,
-            boolean hintsOnly,
-            Boolean checkBlocksIfNotNullForceCheckAllIfTrue) {
-        if (world.isRemote ^ hintsOnly) {
+    static <T> boolean iterate(T object, ItemStack trigger, IStructureElement<T>[] elements, World world,
+            ExtendedFacing extendedFacing, int basePositionX, int basePositionY, int basePositionZ, int basePositionA,
+            int basePositionB, int basePositionC, boolean hintsOnly, Boolean checkBlocksIfNotNullForceCheckAllIfTrue) {
+        if (!world.isRemote && hintsOnly) {
             return false;
         }
 
@@ -341,7 +359,7 @@ public interface IStructureDefinition<T> {
                         basePositionA,
                         basePositionB,
                         basePositionC,
-                        (e, w, x, y, z) -> e.check(object, w, x, y, z),
+                        (e, w, x, y, z, a, b, c) -> e.check(object, w, x, y, z),
                         "check");
             } else {
                 success = StructureUtility.iterateV2(
@@ -354,12 +372,12 @@ public interface IStructureDefinition<T> {
                         basePositionA,
                         basePositionB,
                         basePositionC,
-                        skipBlockUnloaded((e, w, x, y, z) -> e.check(object, w, x, y, z)),
+                        skipBlockUnloaded((e, w, x, y, z, a, b, c) -> e.check(object, w, x, y, z)),
                         "check force");
             }
             if (StructureLibAPI.isDebugEnabled() && success) {
-                StructureLib.LOGGER.info(
-                        "Multi [" + basePositionX + ", " + basePositionY + ", " + basePositionZ + "] pass");
+                StructureLib.LOGGER
+                        .info("Multi [" + basePositionX + ", " + basePositionY + ", " + basePositionZ + "] pass");
             }
             return success;
         } else {
@@ -374,7 +392,7 @@ public interface IStructureDefinition<T> {
                         basePositionA,
                         basePositionB,
                         basePositionC,
-                        ignoreBlockUnloaded((e, w, x, y, z) -> {
+                        ignoreBlockUnloaded((e, w, x, y, z, a, b, c) -> {
                             e.spawnHint(object, world, x, y, z, trigger);
                             return true;
                         }),
@@ -390,7 +408,7 @@ public interface IStructureDefinition<T> {
                         basePositionA,
                         basePositionB,
                         basePositionC,
-                        ignoreBlockUnloaded((e, w, x, y, z) -> {
+                        ignoreBlockUnloaded((e, w, x, y, z, a, b, c) -> {
                             e.placeBlock(object, world, x, y, z, trigger);
                             return true;
                         }),
@@ -402,7 +420,7 @@ public interface IStructureDefinition<T> {
 
     /**
      * Create a new instance of builder.
-     * @return
+     * 
      * @param <T> type of context object
      */
     static <T> StructureDefinition.Builder<T> builder() {

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureElement.java

@@ -3,18 +3,33 @@ package com.gtnewhorizon.structurelib.structure;
 import static com.gtnewhorizon.structurelib.StructureLib.LOGGER;
 import static com.gtnewhorizon.structurelib.StructureLib.PANIC_MODE;
 
-import com.gtnewhorizon.structurelib.StructureLibAPI;
+import java.util.Arrays;
+import java.util.Collections;
 import java.util.function.Consumer;
+import java.util.function.Predicate;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
 import net.minecraft.block.Block;
+import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.entity.player.EntityPlayerMP;
+import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
+import net.minecraft.nbt.NBTTagCompound;
 import net.minecraft.util.IChatComponent;
 import net.minecraft.world.World;
 
+import com.gtnewhorizon.structurelib.StructureLibAPI;
+import com.gtnewhorizon.structurelib.util.ItemStackPredicate;
+import com.gtnewhorizon.structurelib.util.ItemStackPredicate.NBTMode;
+
 /**
- * Use StructureUtility to instantiate
+ * Use StructureUtility to instantiate. These are the building blocks for your {@link IStructureDefinition}. It
+ * represents what a particular element can be and how this particular element should be autoplaced.
  */
 public interface IStructureElement<T> {
+
     boolean check(T t, World world, int x, int y, int z);
 
     boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger);
@@ -24,35 +39,141 @@ public interface IStructureElement<T> {
     /**
      * Try place the block by taking resource from given IItemSource.
      * <p>
-     * You might want to use {@link StructureUtility#survivalPlaceBlock(Block, int, World, int, int, int, IItemSource, EntityPlayerMP)}
+     * You might want to use
+     * {@link StructureUtility#survivalPlaceBlock(Block, int, World, int, int, int, IItemSource, net.minecraft.entity.player.EntityPlayer)}
      * or its overloads to implement this.
      *
      * @param trigger trigger item
      * @param s       drain resources from this place
-     * @param actor   source of action. for very critical errors you can also just send the error messages here, bypassing
-     *                any filter that chatter might have.
+     * @param actor   source of action. for very critical errors you can also just send the error messages here,
+     *                bypassing any filter that chatter might have.
      * @param chatter send error messages here. Caller will choose an appropriate way to forward it to player if the
      *                other fallbacks also fails.
+     * @deprecated caller should call the non deprecated overload. implementor for reusable {@link IStructureElement}
+     *             should still implement this. implementor for private implementations can freely ignore this as long
+     *             as you know the caller will not call this overload.
      */
-    default PlaceResult survivalPlaceBlock(
-            T t,
-            World world,
-            int x,
-            int y,
-            int z,
-            ItemStack trigger,
-            IItemSource s,
-            EntityPlayerMP actor,
-            Consumer<IChatComponent> chatter) {
+    @Deprecated
+    default PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger, IItemSource s,
+            EntityPlayerMP actor, Consumer<IChatComponent> chatter) {
         if (PANIC_MODE) throw new RuntimeException("Panic Tripwire hit");
-        if (StructureLibAPI.isDebugEnabled())
-            LOGGER.error(
-                    "Default implementation of survivalPlaceBlock hit! Things aren't going to work well! IStructureElement class: {}",
-                    getClass().getName());
+        if (StructureLibAPI.isDebugEnabled()) LOGGER.error(
+                "Default implementation of survivalPlaceBlock hit! Things aren't going to work well! IStructureElement class: {}",
+                getClass().getName());
         if (!StructureLibAPI.isBlockTriviallyReplaceable(world, x, y, z, actor)) return PlaceResult.REJECT;
         return PlaceResult.SKIP;
     }
 
+    /**
+     * A simplified version of survivalPlaceBlock. Return null if not implemented.
+     * <p>
+     * <b>BY OVERRIDING THIS TO NULL, YOU ACKNOWLEDGE THAT THE {@link #check(Object, World, int, int, int)} OF THIS
+     * CLASS IS SIDE EFFECT FREE AND CAN HAVE ITS CHECK CALLED WITHOUT BREAKING ANYTHING. OTHERWISE OVERRIDE THE
+     * {@link #survivalPlaceBlock(Object, World, int, int, int, ItemStack, AutoPlaceEnvironment)} TO PROVIDE A
+     * SIDEEFFECT FREE {@link PlaceResult#SKIP}.</b>
+     * <p>
+     * It should be noticed that this filter is only advisory and the actual
+     * {@link #survivalPlaceBlock(Object, World, int, int, int, ItemStack, AutoPlaceEnvironment)} or
+     * {@link #check(Object, World, int, int, int)} are free to reject/accept/place blocks not contained in this list,
+     * e.g. when the element can be placed anywhere in the structure, but no more than 3 overall; when the structure
+     * element cannot know all blocks it will accept at the time of calling; when this is backed by a legacy
+     * {@link IStructureElement} that just didn't implement this API.
+     *
+     * @param trigger trigger item
+     * @param env     autoplacing environment
+     * @return null if not implemented, otherwise an instance describing what kind of blocks will be placed by
+     *         {@link #survivalPlaceBlock(Object, World, int, int, int, ItemStack, AutoPlaceEnvironment)}
+     */
+    @Nullable
+    default BlocksToPlace getBlocksToPlace(T t, World world, int x, int y, int z, ItemStack trigger,
+            AutoPlaceEnvironment env) {
+        return null;
+    }
+
+    /**
+     * Try place the block by taking resource from given {@link IItemSource}.
+     * <p>
+     * You might want to use
+     * {@link StructureUtility#survivalPlaceBlock(Block, int, World, int, int, int, IItemSource, net.minecraft.entity.player.EntityPlayer)}
+     * or its overloads to implement this.
+     * <p>
+     * The default implementation provided will
+     * <ol>
+     * <li>Get {@link BlocksToPlace} via
+     * {@link #getBlocksToPlace(Object, World, int, int, int, ItemStack, AutoPlaceEnvironment)}. If not null
+     * <ol>
+     * <li>call {@link #check(Object, World, int, int, int)}. If this returns {@code true}, {@link PlaceResult#SKIP}
+     * will be returned without further action.</li>
+     * <li>Use the {@link BlocksToPlace} retrieved earlier and passed in {@link IItemSource} to determine an item to
+     * place</li>
+     * <li>Hand over control to
+     * {@link StructureUtility#survivalPlaceBlock(ItemStack, NBTMode, NBTTagCompound, boolean, World, int, int, int, IItemSource, EntityPlayer, Consumer)}</li>
+     * </ol>
+     * </li>
+     * <li>Call legacy
+     * {@link #survivalPlaceBlock(Object, World, int, int, int, ItemStack, IItemSource, EntityPlayerMP, Consumer)} if
+     * {@code env.getActor()} contains an {@link EntityPlayerMP}</li>
+     * <li>Emit warning under debug mode (or throw exception under panic mode), then return
+     * {@link PlaceResult#SKIP}</li>
+     * </ol>
+     * It should be noticed that the default implementation is likely to cause unexpected issues if the
+     * {@link #check(Object, World, int, int, int)} is not side effect free, or is not idempotent. E.g. the
+     * {@link #check(Object, World, int, int, int)} will add current coord to a {@link java.util.List}. As this method
+     * might be invoked at a location that is already accepted, this will cause the machine to have multiple of this
+     * coord in its list.
+     *
+     * @param trigger trigger item
+     * @param env     autoplacing environment
+     */
+    default PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger,
+            AutoPlaceEnvironment env) {
+        BlocksToPlace e = getBlocksToPlace(t, world, x, y, z, trigger, env);
+        IItemSource source = env.getSource();
+        EntityPlayer actor = env.getActor();
+        Consumer<IChatComponent> chatter = env.getChatter();
+        if (e != null) {
+            if (check(t, world, x, y, z)) return PlaceResult.SKIP;
+            if (e.getStacks() == null) {
+                ItemStack taken = source.takeOne(e.getPredicate(), true);
+                return StructureUtility.survivalPlaceBlock(
+                        taken,
+                        NBTMode.EXACT,
+                        taken.stackTagCompound,
+                        true,
+                        world,
+                        x,
+                        y,
+                        z,
+                        source,
+                        actor,
+                        chatter);
+            }
+            for (ItemStack stack : e.getStacks()) {
+                if (!source.takeOne(stack, true)) continue;
+                return StructureUtility.survivalPlaceBlock(
+                        stack,
+                        NBTMode.EXACT,
+                        stack.stackTagCompound,
+                        true,
+                        world,
+                        x,
+                        y,
+                        z,
+                        source,
+                        actor,
+                        chatter);
+            }
+            return PlaceResult.REJECT;
+        }
+        if (actor instanceof EntityPlayerMP)
+            return survivalPlaceBlock(t, world, x, y, z, trigger, source, (EntityPlayerMP) actor, chatter);
+        if (PANIC_MODE) throw new RuntimeException("Panic Tripwire hit");
+        if (StructureLibAPI.isDebugEnabled()) LOGGER.info(
+                "Fallback shim code of survivalPlaceBlock hit! Things aren't going to work well! IStructureElement class: {}",
+                getClass().getName());
+        return PlaceResult.SKIP;
+    }
+
     /**
      * Forget the messed up class dependency graph for now. this is just so convenient.
      */
@@ -101,18 +222,19 @@ public interface IStructureElement<T> {
 
     enum PlaceResult {
         /**
-         * This element either exists already, or does not yet have an implementation for survivalPlaceBlock, or
-         * some other unforeseen situations.
-         * TODO this definition doesn't seem right. Should we separate SKIP from EXISTS, or SKIP from ERROR?
+         * This element either exists already, or does not yet have an implementation for survivalPlaceBlock, or some
+         * other unforeseen situations. TODO this definition doesn't seem right. Should we separate SKIP from EXISTS, or
+         * SKIP from ERROR?
          */
         SKIP,
         /**
-         * This element's space is occupied by other stuff and require player attention, or player missing required resource,
-         * or the block cannot be placed due to obscure mechanisms, or some other unforeseen situations.
+         * This element's space is occupied by other stuff and require player attention, or player missing required
+         * resource, or the block cannot be placed due to obscure mechanisms, or some other unforeseen situations.
          */
         REJECT,
         /**
-         * Autoplace cannot proceed within this tick. To proceed further would require stopping the placement and wait for next round.
+         * Autoplace cannot proceed within this tick. To proceed further would require stopping the placement and wait
+         * for next round.
          */
         STOP,
         /**
@@ -126,4 +248,83 @@ public interface IStructureElement<T> {
          */
         ACCEPT_STOP;
     }
+
+    final class BlocksToPlace {
+
+        public static final BlocksToPlace errored = createEmpty();
+        private final Predicate<ItemStack> predicate;
+        private final Iterable<ItemStack> stacks;
+
+        public static BlocksToPlace createEmpty() {
+            return new BlocksToPlace(s -> false, Collections.emptyList());
+        }
+
+        public static BlocksToPlace create(ItemStack... stacks) {
+            return create(Arrays.asList(stacks));
+        }
+
+        public static BlocksToPlace create(Iterable<ItemStack> stacks) {
+            Predicate<ItemStack> predicate = null;
+
+            for (ItemStack stack : stacks) {
+                ItemStackPredicate p = ItemStackPredicate.from(stack, NBTMode.EXACT);
+                if (predicate == null) predicate = p;
+                else predicate = predicate.or(p);
+            }
+
+            return new BlocksToPlace(predicate, stacks);
+        }
+
+        public static BlocksToPlace create(Block block, int meta) {
+            Item itemBlock = Item.getItemFromBlock(block);
+            if (itemBlock instanceof ISpecialItemBlock) {
+                meta = ((ISpecialItemBlock) itemBlock).getItemMetaFromBlockMeta(block, meta);
+            }
+            return create(itemBlock, meta);
+        }
+
+        public static BlocksToPlace create(Item item, int meta) {
+            return new BlocksToPlace(
+                    ItemStackPredicate.from(item).setMeta(meta),
+                    Collections.singletonList(new ItemStack(item, 1, meta)));
+        }
+
+        public static BlocksToPlace create(ItemStack itemStack) {
+            return new BlocksToPlace(ItemStackPredicate.from(itemStack), Collections.singletonList(itemStack));
+        }
+
+        public static BlocksToPlace create(Predicate<ItemStack> predicate) {
+            return new BlocksToPlace(predicate, null);
+        }
+
+        BlocksToPlace(Predicate<ItemStack> predicate, Iterable<ItemStack> stacks) {
+            this.predicate = predicate;
+            this.stacks = stacks;
+        }
+
+        /**
+         * Get the blocks to place filter. This is usually slower as it requires walking through inventories one by one.
+         * <p>
+         * Suitable for use with {@link IItemSource#takeOne(Predicate, boolean)}
+         *
+         * @return a predicate. never null.
+         */
+        @Nonnull
+        public Predicate<ItemStack> getPredicate() {
+            return predicate;
+        }
+
+        /**
+         * Get the ItemStacks that this one is known to accept. Can be null if this info is not available at the time
+         * this instance is constructed.
+         * <p>
+         * Suitable for use with {@link IItemSource#takeOne(ItemStack, boolean)}.
+         * <p>
+         * This should be equivalent to the predicate returned from {@link #getPredicate()}
+         */
+        @Nullable
+        public Iterable<ItemStack> getStacks() {
+            return stacks;
+        }
+    }
 }

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureElementChain.java

@@ -3,15 +3,22 @@ package com.gtnewhorizon.structurelib.structure;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Consumer;
+import java.util.function.Predicate;
+
+import javax.annotation.Nullable;
+
 import net.minecraft.entity.player.EntityPlayerMP;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.IChatComponent;
 import net.minecraft.world.World;
 
+import com.google.common.collect.Iterables;
+
 /**
  * Use StructureUtility to instantiate
  */
 public interface IStructureElementChain<T> extends IStructureElement<T> {
+
     IStructureElement<T>[] fallbacks();
 
     @Override
@@ -44,17 +51,26 @@ public interface IStructureElementChain<T> extends IStructureElement<T> {
         return false;
     }
 
+    @Nullable
     @Override
-    default PlaceResult survivalPlaceBlock(
-            T t,
-            World world,
-            int x,
-            int y,
-            int z,
-            ItemStack trigger,
-            IItemSource s,
-            EntityPlayerMP actor,
-            Consumer<IChatComponent> chatter) {
+    default BlocksToPlace getBlocksToPlace(T t, World world, int x, int y, int z, ItemStack trigger,
+            AutoPlaceEnvironment env) {
+        Predicate<ItemStack> predicate = null;
+        List<Iterable<ItemStack>> is = new ArrayList<>();
+        for (IStructureElement<T> fallback : fallbacks()) {
+            BlocksToPlace e = fallback.getBlocksToPlace(t, world, x, y, z, trigger, env);
+            if (e == null) continue;
+            if (predicate == null) predicate = e.getPredicate();
+            else predicate = predicate.or(e.getPredicate());
+            is.add(e.getStacks());
+        }
+        if (predicate == null) return null;
+        return new BlocksToPlace(predicate, Iterables.concat(is));
+    }
+
+    @Override
+    default PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger, IItemSource s,
+            EntityPlayerMP actor, Consumer<IChatComponent> chatter) {
         boolean haveSkip = false;
         List<IChatComponent> bufferedNoise = new ArrayList<>();
         for (IStructureElement<T> fallback : fallbacks()) {
@@ -74,4 +90,28 @@ public interface IStructureElementChain<T> extends IStructureElement<T> {
         // TODO need reconsider to ensure this is the right course of action
         return haveSkip ? PlaceResult.SKIP : PlaceResult.REJECT;
     }
+
+    @Override
+    default PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger,
+            AutoPlaceEnvironment env) {
+        boolean haveSkip = false;
+        List<IChatComponent> bufferedNoise = new ArrayList<>();
+        for (IStructureElement<T> fallback : fallbacks()) {
+            PlaceResult result = fallback
+                    .survivalPlaceBlock(t, world, x, y, z, trigger, env.withChatter(bufferedNoise::add));
+            switch (result) {
+                case REJECT:
+                    break;
+                case SKIP:
+                    haveSkip = true;
+                    break;
+                default:
+                    return result;
+            }
+        }
+        // dump all that noise back into upstream
+        bufferedNoise.forEach(env.getChatter());
+        // TODO need reconsider to ensure this is the right course of action
+        return haveSkip ? PlaceResult.SKIP : PlaceResult.REJECT;
+    }
 }

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureElementCheckOnly.java

@@ -1,12 +1,14 @@
 package com.gtnewhorizon.structurelib.structure;
 
 import java.util.function.Consumer;
+
 import net.minecraft.entity.player.EntityPlayerMP;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.IChatComponent;
 import net.minecraft.world.World;
 
 public interface IStructureElementCheckOnly<T> extends IStructureElement<T> {
+
     @Override
     default boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
         return false;
@@ -18,16 +20,14 @@ public interface IStructureElementCheckOnly<T> extends IStructureElement<T> {
     }
 
     @Override
-    default PlaceResult survivalPlaceBlock(
-            T t,
-            World world,
-            int x,
-            int y,
-            int z,
-            ItemStack trigger,
-            IItemSource s,
-            EntityPlayerMP actor,
-            Consumer<IChatComponent> chatter) {
+    default PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger, IItemSource s,
+            EntityPlayerMP actor, Consumer<IChatComponent> chatter) {
+        return PlaceResult.SKIP;
+    }
+
+    @Override
+    default PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger,
+            AutoPlaceEnvironment env) {
         return PlaceResult.SKIP;
     }
 }

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureElementDeferred.java

@@ -3,4 +3,5 @@ package com.gtnewhorizon.structurelib.structure;
 /**
  * Use StructureUtility to instantiate
  */
-public interface IStructureElementDeferred<T> extends IStructureElement<T> {}
+public interface IStructureElementDeferred<T> extends IStructureElement<T> {
+}

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureElementNoPlacement.java

@@ -1,28 +1,28 @@
 package com.gtnewhorizon.structurelib.structure;
 
 import java.util.function.Consumer;
+
 import net.minecraft.entity.player.EntityPlayerMP;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.IChatComponent;
 import net.minecraft.world.World;
 
 public interface IStructureElementNoPlacement<T> extends IStructureElement<T> {
+
     @Override
     default boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
         return false;
     }
 
     @Override
-    default PlaceResult survivalPlaceBlock(
-            T t,
-            World world,
-            int x,
-            int y,
-            int z,
-            ItemStack trigger,
-            IItemSource s,
-            EntityPlayerMP actor,
-            Consumer<IChatComponent> chatter) {
+    default PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger, IItemSource s,
+            EntityPlayerMP actor, Consumer<IChatComponent> chatter) {
+        return PlaceResult.REJECT;
+    }
+
+    @Override
+    default PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger,
+            AutoPlaceEnvironment env) {
         return PlaceResult.REJECT;
     }
 

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureNavigate.java

@@ -1,6 +1,7 @@
 package com.gtnewhorizon.structurelib.structure;
 
 import java.util.function.Consumer;
+
 import net.minecraft.entity.player.EntityPlayerMP;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.IChatComponent;
@@ -10,6 +11,7 @@ import net.minecraft.world.World;
  * Use StructureUtility to instantiate
  */
 interface IStructureNavigate<T> extends IStructureElement<T> {
+
     @Override
     default boolean check(T t, World world, int x, int y, int z) {
         return true;
@@ -26,16 +28,14 @@ interface IStructureNavigate<T> extends IStructureElement<T> {
     }
 
     @Override
-    default PlaceResult survivalPlaceBlock(
-            T t,
-            World world,
-            int x,
-            int y,
-            int z,
-            ItemStack trigger,
-            IItemSource s,
-            EntityPlayerMP actor,
-            Consumer<IChatComponent> chatter) {
+    default PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger, IItemSource s,
+            EntityPlayerMP actor, Consumer<IChatComponent> chatter) {
+        return PlaceResult.SKIP;
+    }
+
+    @Override
+    default PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger,
+            AutoPlaceEnvironment env) {
         return PlaceResult.SKIP;
     }
 

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureWalker.java

@@ -2,36 +2,42 @@ package com.gtnewhorizon.structurelib.structure;
 
 import net.minecraft.world.World;
 
-public interface IStructureWalker<T> {
-    boolean visit(IStructureElement<T> element, World world, int x, int y, int z);
+interface IStructureWalker<T> {
 
-    default boolean blockNotLoaded(IStructureElement<T> element, World world, int x, int y, int z) {
+    boolean visit(IStructureElement<T> element, World world, int x, int y, int z, int a, int b, int c);
+
+    default boolean blockNotLoaded(IStructureElement<T> element, World world, int x, int y, int z, int a, int b,
+            int c) {
         return false;
     }
 
     static <T> IStructureWalker<T> ignoreBlockUnloaded(IStructureWalker<T> walker) {
         return new IStructureWalker<T>() {
+
             @Override
-            public boolean visit(IStructureElement<T> element, World world, int x, int y, int z) {
-                return walker.visit(element, world, x, y, z);
+            public boolean visit(IStructureElement<T> element, World world, int x, int y, int z, int a, int b, int c) {
+                return walker.visit(element, world, x, y, z, a, b, c);
             }
 
             @Override
-            public boolean blockNotLoaded(IStructureElement<T> element, World world, int x, int y, int z) {
-                return walker.visit(element, world, x, y, z);
+            public boolean blockNotLoaded(IStructureElement<T> element, World world, int x, int y, int z, int a, int b,
+                    int c) {
+                return walker.visit(element, world, x, y, z, a, b, c);
             }
         };
     }
 
     static <T> IStructureWalker<T> skipBlockUnloaded(IStructureWalker<T> walker) {
         return new IStructureWalker<T>() {
+
             @Override
-            public boolean visit(IStructureElement<T> element, World world, int x, int y, int z) {
-                return walker.visit(element, world, x, y, z);
+            public boolean visit(IStructureElement<T> element, World world, int x, int y, int z, int a, int b, int c) {
+                return walker.visit(element, world, x, y, z, a, b, c);
             }
 
             @Override
-            public boolean blockNotLoaded(IStructureElement<T> element, World world, int x, int y, int z) {
+            public boolean blockNotLoaded(IStructureElement<T> element, World world, int x, int y, int z, int a, int b,
+                    int c) {
                 return true;
             }
         };

src/main/java/com/gtnewhorizon/structurelib/structure/ISurvivalBuildEnvironment.java

@@ -0,0 +1,41 @@
+package com.gtnewhorizon.structurelib.structure;
+
+import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.item.ItemStack;
+import net.minecraft.world.World;
+
+import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
+
+/*
+ * Architecture notes: this should never get any callback from survival build. All structure significant code belongs
+ * within the IStructureElement. This will make the user easier to maintain the IStructureDefinition. Structure Element
+ * knows the most about what this structure element should do, not the caller.
+ */
+public interface ISurvivalBuildEnvironment {
+
+    /**
+     * Get the source of the items. This will be invoked exactly once per structure element build.
+     * <p>
+     * If the call chain ever got into the old API, this will be called at least once per
+     * {@link IStructureDefinition#survivalBuild(Object, ItemStack, String, World, ExtendedFacing, int, int, int, int, int, int, int, ISurvivalBuildEnvironment, boolean)}
+     * call.
+     */
+    IItemSource getSource();
+
+    /**
+     * Get the origin of action. This will be invoked at least once per
+     * {@link IStructureDefinition#survivalBuild(Object, ItemStack, String, World, ExtendedFacing, int, int, int, int, int, int, int, ISurvivalBuildEnvironment, boolean)}
+     * call.
+     */
+    EntityPlayer getActor();
+
+    /**
+     * Create a default implementation with three parameters all being constants.
+     *
+     * @param source from where to drain resource
+     * @param actor  source of action
+     */
+    static ISurvivalBuildEnvironment create(IItemSource source, EntityPlayer actor) {
+        return new DefaultSurvivalBuildEnvironment(source, actor);
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/structure/ITierConverter.java

@@ -9,5 +9,6 @@ import net.minecraft.block.Block;
  */
 @FunctionalInterface
 public interface ITierConverter<TIER> {
+
     TIER convert(Block block, int meta);
 }

src/main/java/com/gtnewhorizon/structurelib/structure/IWithExtendedContext.java

@@ -3,7 +3,7 @@ package com.gtnewhorizon.structurelib.structure;
 /**
  * Implement this and use {@link StructureUtility#withContext(IStructureElement)} in case you need to record some
  * temporary states that don't need to live in your main context, which would usually live for the whole lifetime of the
- * structure than just during structure check. Usually just save some few bytes, but becomes non trivial if you need to
+ * structure than just during structure check. Usually just save some few bytes, but becomes non-trivial if you need to
  * record too much stuff.
  * <p>
  * You will have to reset the context yourself though. The API can't guess when the old context becomes invalid.
@@ -11,5 +11,6 @@ package com.gtnewhorizon.structurelib.structure;
  * @param <CTX> the temporary state context
  */
 public interface IWithExtendedContext<CTX> {
+
     CTX getCurrentContext();
 }

src/main/java/com/gtnewhorizon/structurelib/structure/LazyStructureElement.java

@@ -2,12 +2,16 @@ package com.gtnewhorizon.structurelib.structure;
 
 import java.util.function.Consumer;
 import java.util.function.Function;
+
+import javax.annotation.Nullable;
+
 import net.minecraft.entity.player.EntityPlayerMP;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.IChatComponent;
 import net.minecraft.world.World;
 
 class LazyStructureElement<T> implements IStructureElementDeferred<T> {
+
     private Function<T, IStructureElement<T>> to;
     private IStructureElement<T> elem;
 
@@ -38,17 +42,22 @@ class LazyStructureElement<T> implements IStructureElementDeferred<T> {
         return get(t).spawnHint(t, world, x, y, z, trigger);
     }
 
+    @Nullable
     @Override
-    public PlaceResult survivalPlaceBlock(
-            T t,
-            World world,
-            int x,
-            int y,
-            int z,
-            ItemStack trigger,
-            IItemSource s,
-            EntityPlayerMP actor,
-            Consumer<IChatComponent> chatter) {
+    public BlocksToPlace getBlocksToPlace(T t, World world, int x, int y, int z, ItemStack trigger,
+            AutoPlaceEnvironment env) {
+        return get(t).getBlocksToPlace(t, world, x, y, z, trigger, env);
+    }
+
+    @Override
+    public PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger, IItemSource s,
+            EntityPlayerMP actor, Consumer<IChatComponent> chatter) {
         return get(t).survivalPlaceBlock(t, world, x, y, z, trigger, s, actor, chatter);
     }
+
+    @Override
+    public PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger,
+            AutoPlaceEnvironment env) {
+        return get(t).survivalPlaceBlock(t, world, x, y, z, trigger, env);
+    }
 }

src/main/java/com/gtnewhorizon/structurelib/structure/StructureDefinition.java

@@ -2,30 +2,32 @@ package com.gtnewhorizon.structurelib.structure;
 
 import static com.gtnewhorizon.structurelib.structure.StructureUtility.*;
 
-import com.gtnewhorizon.structurelib.StructureLibAPI;
-import com.gtnewhorizon.structurelib.util.Vec3Impl;
 import java.util.*;
 import java.util.stream.Collectors;
 
+import com.gtnewhorizon.structurelib.util.Vec3Impl;
+
 public class StructureDefinition<T> implements IStructureDefinition<T> {
+
     private final Map<Character, IStructureElement<T>> elements;
     private final Map<String, String> shapes;
     private final Map<String, IStructureElement<T>[]> structures;
+    private final Map<String, Set<Vec3Impl>> occupiedSpaces;
 
     public static <B> Builder<B> builder() {
         return new Builder<>();
     }
 
-    private StructureDefinition(
-            Map<Character, IStructureElement<T>> elements,
-            Map<String, String> shapes,
-            Map<String, IStructureElement<T>[]> structures) {
+    private StructureDefinition(Map<Character, IStructureElement<T>> elements, Map<String, String> shapes,
+            Map<String, IStructureElement<T>[]> structures, Map<String, Set<Vec3Impl>> occupiedSpaces) {
         this.elements = elements;
         this.shapes = shapes;
         this.structures = structures;
+        this.occupiedSpaces = occupiedSpaces;
     }
 
     public static class Builder<T> {
+
         private static final char A = '\uA000';
         private static final char B = '\uB000';
         private static final char C = '\uC000';
@@ -33,11 +35,13 @@ public class StructureDefinition<T> implements IStructureDefinition<T> {
         private final Map<Vec3Impl, Character> navigates;
         private final Map<Character, IStructureElement<T>> elements;
         private final Map<String, String> shapes;
+        private final Map<String, Set<Vec3Impl>> occupiedSpaces;
 
         private Builder() {
             navigates = new HashMap<>();
             elements = new HashMap<>();
             shapes = new HashMap<>();
+            occupiedSpaces = new HashMap<>();
         }
 
         public Map<Character, IStructureElement<T>> getElements() {
@@ -49,21 +53,25 @@ public class StructureDefinition<T> implements IStructureDefinition<T> {
         }
 
         /**
-         * Adds shape
-         * + is anything but air
-         * - is air checks
-         * space bar is skip
-         * ~ is also skip (but marks controller position, optional and logically it is a space...)
-         * rest needs to be defined
+         * Adds shape. Shape is a two-dimensional string array. Each <b>character</b> inside any of these strings will
+         * be later mapped to a particular type of {@link IStructureElement} as indicated by
+         * {@link #addElement(Character, IStructureElement)}.
          * <p>
-         * next char is next block(a)
-         * next string is next line(b)
-         * next string[] is next slice(c)
+         * next char is next block(a) next string is next line(b) next string[] is next slice(c)
+         * <p>
+         * There are a few special reserved characters that are pre-mapped to some common structure elements
+         * <ul>
+         * <li>+ is anything but air</li>
+         * <li>- is air checks</li>
+         * <li>space bar is skip</li>
+         * <li>~ is also skip (but marks controller position, not optional)</li>
+         * <li>char {@code A000-FFFF} range is reserved for generated skips</li>
+         * </ul>
          * <p>
-         * char A000-FFFF range is reserved for generated skips
          *
          * @param name           unlocalized/code name
-         * @param structurePiece generated or written struct - DO NOT STORE IT ANYWHERE, or at least set them to null afterwards
+         * @param structurePiece generated or written struct - DO NOT STORE IT ANYWHERE, or at least set them to null
+         *                       afterwards
          * @return this builder
          */
         public Builder<T> addShape(String name, String[][] structurePiece) {
@@ -80,22 +88,37 @@ public class StructureDefinition<T> implements IStructureDefinition<T> {
                 }
                 builder.setLength(builder.length() - 1);
             }
+            Set<Vec3Impl> occupiedSpace = new HashSet<>();
+            // these track the global current location
+            int aa = 0, bb = 0, cc = 0;
+            // these track the vec3 towards next meaningful element
             int a = 0, b = 0, c = 0;
+            // I do know these are pretty bad variable naming, but I have no better idea
             for (int i = 0; i < builder.length(); i++) {
                 char ch = builder.charAt(i);
-                if (ch == ' ' || ch == '~') {
+                if (ch == ' ') {
                     builder.setCharAt(i, A);
                     ch = A;
+                } else if (ch == '~') {
+                    builder.setCharAt(i, A);
+                    ch = A;
+                    occupiedSpace.add(Vec3Impl.getFromPool(aa, bb, cc));
                 }
                 if (ch == A) {
+                    aa++;
                     a++;
                 } else if (ch == B) {
+                    aa = 0;
                     a = 0;
+                    bb++;
                     b++;
                 } else if (ch == C) {
+                    aa = 0;
+                    bb = 0;
                     a = 0;
                     b = 0;
                     c++;
+                    cc++;
                 } else if (a != 0 || b != 0 || c != 0) {
                     Vec3Impl vec3 = new Vec3Impl(a, b, c);
                     Character navigate = navigates.get(vec3);
@@ -105,12 +128,19 @@ public class StructureDefinition<T> implements IStructureDefinition<T> {
                         addElement(navigate, step(vec3));
                     }
                     builder.setCharAt(i - 1, navigate);
+                    occupiedSpace.add(Vec3Impl.getFromPool(aa, bb, cc));
+                    aa++;
                     a = 0;
                     b = 0;
                     c = 0;
+                } else {
+                    occupiedSpace.add(Vec3Impl.getFromPool(aa, bb, cc));
+                    aa++;
                 }
             }
 
+            occupiedSpaces.put(name, occupiedSpace);
+
             String built = builder.toString().replaceAll("[\\uA000\\uB000\\uC000]", "");
 
             if (built.contains("+")) {
@@ -123,33 +153,42 @@ public class StructureDefinition<T> implements IStructureDefinition<T> {
             return this;
         }
 
+        /**
+         * @deprecated use the unboxed version
+         */
+        @Deprecated
         public Builder<T> addElement(Character name, IStructureElement<T> structurePiece) {
             elements.putIfAbsent(name, structurePiece);
             return this;
         }
 
+        public Builder<T> addElement(char name, IStructureElement<T> structurePiece) {
+            elements.putIfAbsent(name, structurePiece);
+            return this;
+        }
+
         public IStructureDefinition<T> build() {
             Map<String, IStructureElement<T>[]> structures = compileStructureMap();
-            if (StructureLibAPI.isDebugEnabled()) {
-                return new StructureDefinition<>(new HashMap<>(elements), new HashMap<>(shapes), structures);
-            } else {
-                return structures::get;
-            }
+            return new StructureDefinition<>(
+                    new HashMap<>(elements),
+                    new HashMap<>(shapes),
+                    structures,
+                    occupiedSpaces);
         }
 
         @SuppressWarnings("unchecked")
         private Map<String, IStructureElement<T>[]> compileElementSetMap() {
             Set<Integer> missing = findMissing();
             if (missing.isEmpty()) {
-                return shapes.entrySet().stream().collect(Collectors.toMap(Map.Entry::getKey, e -> e.getValue()
-                        .chars()
-                        .mapToObj(c -> (char) c)
-                        .distinct()
-                        .map(elements::get)
-                        .toArray(IStructureElement[]::new)));
+                return shapes.entrySet().stream().collect(
+                        Collectors.toMap(
+                                Map.Entry::getKey,
+                                e -> e.getValue().chars().mapToObj(c -> (char) c).distinct().map(elements::get)
+                                        .toArray(IStructureElement[]::new)));
             } else {
-                throw new RuntimeException("Missing Structure Element bindings for (chars as integers): "
-                        + Arrays.toString(missing.toArray()));
+                throw new RuntimeException(
+                        "Missing Structure Element bindings for (chars as integers): "
+                                + Arrays.toString(missing.toArray()));
             }
         }
 
@@ -157,22 +196,21 @@ public class StructureDefinition<T> implements IStructureDefinition<T> {
         private Map<String, IStructureElement<T>[]> compileStructureMap() {
             Set<Integer> missing = findMissing();
             if (missing.isEmpty()) {
-                return shapes.entrySet().stream().collect(Collectors.toMap(Map.Entry::getKey, e -> e.getValue()
-                        .chars()
-                        .mapToObj(c -> elements.get((char) c))
-                        .toArray(IStructureElement[]::new)));
+                return shapes.entrySet().stream().collect(
+                        Collectors.toMap(
+                                Map.Entry::getKey,
+                                e -> e.getValue().chars().mapToObj(c -> elements.get((char) c))
+                                        .toArray(IStructureElement[]::new)));
             } else {
-                throw new RuntimeException("Missing Structure Element bindings for (chars as integers): "
-                        + Arrays.toString(missing.toArray()));
+                throw new RuntimeException(
+                        "Missing Structure Element bindings for (chars as integers): "
+                                + Arrays.toString(missing.toArray()));
             }
         }
 
         private Set<Integer> findMissing() {
-            return shapes.values().stream()
-                    .flatMapToInt(CharSequence::chars)
-                    .filter(i -> !elements.containsKey((char) i))
-                    .boxed()
-                    .collect(Collectors.toSet());
+            return shapes.values().stream().flatMapToInt(CharSequence::chars)
+                    .filter(i -> !elements.containsKey((char) i)).boxed().collect(Collectors.toSet());
         }
     }
 
@@ -194,4 +232,11 @@ public class StructureDefinition<T> implements IStructureDefinition<T> {
         if (elements == null) throw new NoSuchElementException(name);
         return elements;
     }
+
+    @Override
+    public boolean isContainedInStructure(String name, int offsetA, int offsetB, int offsetC) {
+        Set<Vec3Impl> occupiedSpace = occupiedSpaces.get(name);
+        if (occupiedSpace == null) throw new NoSuchElementException(name);
+        return occupiedSpace.contains(new Vec3Impl(offsetA, offsetB, offsetC));
+    }
 }

src/main/java/com/gtnewhorizon/structurelib/structure/StructureElement_Bridge.java

@@ -0,0 +1,26 @@
+package com.gtnewhorizon.structurelib.structure;
+
+import java.util.function.Consumer;
+
+import net.minecraft.entity.player.EntityPlayerMP;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.IChatComponent;
+import net.minecraft.world.World;
+
+/**
+ * Internal bridge class for easing implementation
+ */
+abstract class StructureElement_Bridge<T> implements IStructureElement<T> {
+
+    // seal the deprecated method to prevent accidental overrides
+    @Deprecated
+    @Override
+    public final PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger, IItemSource s,
+            EntityPlayerMP actor, Consumer<IChatComponent> chatter) {
+        return survivalPlaceBlock(t, world, x, y, z, trigger, AutoPlaceEnvironment.fromLegacy(s, actor, chatter));
+    }
+
+    // clear the default implementation. we don't need that.
+    public abstract PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger,
+            AutoPlaceEnvironment env);
+}

src/main/java/com/gtnewhorizon/structurelib/structure/SurvivalBuildStructureWalker.java

@@ -1,34 +1,48 @@
 package com.gtnewhorizon.structurelib.structure;
 
-import com.gtnewhorizon.structurelib.StructureLibAPI;
-import com.gtnewhorizon.structurelib.structure.IStructureElement.PlaceResult;
-import net.minecraft.entity.player.EntityPlayerMP;
 import net.minecraft.item.ItemStack;
 import net.minecraft.world.World;
 
+import com.gtnewhorizon.structurelib.StructureLibAPI;
+import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
+import com.gtnewhorizon.structurelib.structure.IStructureElement.PlaceResult;
+
 class SurvivalBuildStructureWalker<T> implements IStructureWalker<T> {
-    private final T object;
-    private final ItemStack trigger;
-    private final IItemSource source;
-    private final EntityPlayerMP actor;
+
+    final T object;
+    final ItemStack trigger;
     private final int elementBudget;
+    private final ISurvivalBuildEnvironment params;
     private final boolean check;
     private int built = -1;
 
-    public SurvivalBuildStructureWalker(
-            T object, ItemStack trigger, IItemSource source, EntityPlayerMP actor, int elementBudget, boolean check) {
+    private final AutoPlaceEnvironment env;
+
+    public SurvivalBuildStructureWalker(T object, ItemStack trigger, int elementBudget,
+            ISurvivalBuildEnvironment params, IStructureDefinition<?> definition, String piece, ExtendedFacing facing,
+            int[] baseOffsetABC, boolean check) {
         this.object = object;
         this.trigger = trigger;
-        this.source = source;
-        this.actor = actor;
         this.elementBudget = elementBudget;
+        this.params = params;
         this.check = check;
+
+        env = new AutoPlaceEnvironment(
+                params.getActor(),
+                params.getActor()::addChatComponentMessage,
+                definition,
+                piece,
+                facing,
+                baseOffsetABC);
     }
 
     @Override
-    public boolean visit(IStructureElement<T> element, World world, int x, int y, int z) {
-        PlaceResult placeResult = element.survivalPlaceBlock(
-                object, world, x, y, z, trigger, source, actor, actor::addChatComponentMessage);
+    public boolean visit(IStructureElement<T> element, World world, int x, int y, int z, int a, int b, int c) {
+        env.offsetABC[0] = a;
+        env.offsetABC[1] = b;
+        env.offsetABC[2] = c;
+        env.setSource(params.getSource());
+        PlaceResult placeResult = element.survivalPlaceBlock(object, world, x, y, z, trigger, env);
         if (placeResult != PlaceResult.SKIP && built == -1) built = 0;
         switch (placeResult) {
             case SKIP:
@@ -37,7 +51,7 @@ class SurvivalBuildStructureWalker<T> implements IStructureWalker<T> {
                 if (check) element.check(object, world, x, y, z);
                 return ++built < elementBudget;
             case REJECT:
-                StructureLibAPI.markHintParticleError(actor, world, x, y, z);
+                StructureLibAPI.markHintParticleError(params.getActor(), world, x, y, z);
                 return false;
             case ACCEPT_STOP:
                 if (check) element.check(object, world, x, y, z);

src/main/java/com/gtnewhorizon/structurelib/structure/adders/IBlockAdder.java

@@ -3,6 +3,7 @@ package com.gtnewhorizon.structurelib.structure.adders;
 import net.minecraft.block.Block;
 
 public interface IBlockAdder<T> {
+
     /**
      * Callback on block added, needs to check if block is valid (and add it)
      *

src/main/java/com/gtnewhorizon/structurelib/structure/adders/ITileAdder.java

@@ -3,6 +3,7 @@ package com.gtnewhorizon.structurelib.structure.adders;
 import net.minecraft.tileentity.TileEntity;
 
 public interface ITileAdder<T> {
+
     /**
      * Callback to add hatch, needs to check if tile is valid (and add it)
      *

src/main/java/com/gtnewhorizon/structurelib/structure/package-info.java

@@ -1,7 +1,7 @@
 /**
  * This package provide support for multiblock structure checking.
  * <p>
- * All public stuff in this package and its subpackages are considered part of the public API.
- * Backwards compatibility is maintained to the maximum extend possible.
+ * All public stuff in this package and its subpackages are considered part of the public API. Backwards compatibility
+ * is maintained to the maximum extend possible.
  */
 package com.gtnewhorizon.structurelib.structure;

src/main/java/com/gtnewhorizon/structurelib/util/InventoryIterable.java

@@ -2,10 +2,12 @@ package com.gtnewhorizon.structurelib.util;
 
 import java.util.Iterator;
 import java.util.NoSuchElementException;
+
 import net.minecraft.inventory.IInventory;
 import net.minecraft.item.ItemStack;
 
 public class InventoryIterable<Inv extends IInventory> implements Iterable<ItemStack> {
+
     private final Inv inv;
     private final int maxSlot;
 
@@ -25,6 +27,7 @@ public class InventoryIterable<Inv extends IInventory> implements Iterable<ItemS
     @Override
     public Iterator<ItemStack> iterator() {
         return new Iterator<ItemStack>() {
+
             private int ptr = 0;
 
             @Override

src/main/java/com/gtnewhorizon/structurelib/util/InventoryUtility.java

@@ -1,32 +1,27 @@
 /**
- * Copyright (c) 2022, glee8e
- * This file is part of StructureLib.
+ * Copyright (c) 2022, glee8e This file is part of StructureLib.
  * <p>
- * StructureLib is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
+ * StructureLib is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General
+ * Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any
+ * later version.
  * <p>
- * StructureLib is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Lesser General Public License for more details.
+ * StructureLib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+ * details.
  * <p>
- * You should have received a copy of the GNU Lesser General Public License
- * along with Foobar; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ * You should have received a copy of the GNU Lesser General Public License along with Foobar; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  */
 package com.gtnewhorizon.structurelib.util;
 
-import com.gtnewhorizon.gtnhlib.util.map.ItemStackMap;
-import com.gtnewhorizon.structurelib.util.InventoryUtility.ItemStackExtractor.APIType;
-import com.gtnewhorizon.structurelib.util.ItemStackPredicate.NBTMode;
 import java.util.*;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.function.Function;
 import java.util.function.Predicate;
+
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
+
 import net.minecraft.entity.player.EntityPlayerMP;
 import net.minecraft.entity.player.InventoryPlayer;
 import net.minecraft.init.Items;
@@ -34,10 +29,15 @@ import net.minecraft.inventory.IInventory;
 import net.minecraft.inventory.InventoryEnderChest;
 import net.minecraft.item.ItemStack;
 
+import com.gtnewhorizon.gtnhlib.util.map.ItemStackMap;
+import com.gtnewhorizon.structurelib.util.InventoryUtility.ItemStackExtractor.APIType;
+import com.gtnewhorizon.structurelib.util.ItemStackPredicate.NBTMode;
+
 /**
  * This class is part of API, but is not stable. Use at your own risk.
  */
 public class InventoryUtility {
+
     private static final SortedRegistry<ItemStackExtractor> stackExtractors = new SortedRegistry<>();
     private static final List<Predicate<? super EntityPlayerMP>> enableEnder = new CopyOnWriteArrayList<>();
     /**
@@ -47,6 +47,7 @@ public class InventoryUtility {
 
     static {
         inventoryProviders.register("5000-main-inventory", new InventoryProvider<InventoryIterable<InventoryPlayer>>() {
+
             @Override
             public InventoryIterable<InventoryPlayer> getInventory(EntityPlayerMP player) {
                 return new InventoryIterable<>(player.inventory, player.inventory.mainInventory.length);
@@ -59,8 +60,9 @@ public class InventoryUtility {
                 inv.getInventory().player.inventoryContainer.detectAndSendChanges();
             }
         });
-        inventoryProviders.register(
-                "7000-ender-inventory", new InventoryProvider<InventoryIterable<InventoryEnderChest>>() {
+        inventoryProviders
+                .register("7000-ender-inventory", new InventoryProvider<InventoryIterable<InventoryEnderChest>>() {
+
                     @Override
                     public InventoryIterable<InventoryEnderChest> getInventory(EntityPlayerMP player) {
                         if (enableEnder.stream().anyMatch(p -> p.test(player)))
@@ -86,8 +88,8 @@ public class InventoryUtility {
         stackExtractors.register(key, val);
     }
 
-    public static <Inv extends IInventory> void registerStackExtractor(
-            String key, Function<ItemStack, ? extends Inv> extractor) {
+    public static <Inv extends IInventory> void registerStackExtractor(String key,
+            Function<ItemStack, ? extends Inv> extractor) {
         registerStackExtractor(key, newItemStackProvider(extractor));
     }
 
@@ -95,8 +97,8 @@ public class InventoryUtility {
         inventoryProviders.register(key, val);
     }
 
-    public static <Inv extends IInventory> void registerInventoryProvider(
-            String key, Function<EntityPlayerMP, ? extends Inv> extractor) {
+    public static <Inv extends IInventory> void registerInventoryProvider(String key,
+            Function<EntityPlayerMP, ? extends Inv> extractor) {
         registerInventoryProvider(key, newInventoryProvider(extractor));
     }
 
@@ -107,6 +109,7 @@ public class InventoryUtility {
     public static <Inv extends IInventory> InventoryProvider<InventoryIterable<Inv>> newInventoryProvider(
             Function<EntityPlayerMP, ? extends Inv> extractor) {
         return new InventoryProvider<InventoryIterable<Inv>>() {
+
             @Override
             public InventoryIterable<Inv> getInventory(EntityPlayerMP player) {
                 Inv inv = extractor.apply(player);
@@ -122,24 +125,26 @@ public class InventoryUtility {
 
     public static ItemStackExtractor newItemStackProvider(Function<ItemStack, ? extends IInventory> extractor) {
         return new ItemStackExtractor() {
+
             @Override
             public boolean isAPIImplemented(APIType type) {
                 return type == APIType.MAIN;
             }
 
             @Override
-            public int takeFromStack(
-                    Predicate<ItemStack> predicate,
-                    boolean simulate,
-                    int count,
-                    ItemStackCounter store,
-                    ItemStack stack,
-                    ItemStack filter,
-                    EntityPlayerMP player) {
+            public int takeFromStack(Predicate<ItemStack> predicate, boolean simulate, int count,
+                    ItemStackCounter store, ItemStack stack, ItemStack filter, EntityPlayerMP player) {
                 IInventory inv = extractor.apply(stack);
                 if (inv == null) return 0;
                 int found = takeFromInventory(
-                        new InventoryIterable<>(inv), predicate, simulate, count, store, filter, player, false);
+                        new InventoryIterable<>(inv),
+                        predicate,
+                        simulate,
+                        count,
+                        store,
+                        filter,
+                        player,
+                        false);
                 if (found > 0) inv.markDirty();
                 return found;
             }
@@ -147,8 +152,8 @@ public class InventoryUtility {
     }
 
     /**
-     * take count amount of stacks that matches given filter. might take partial amount of stuff, so simulation is suggested
-     * if you ever need to take more than one.
+     * take count amount of stacks that matches given filter. might take partial amount of stuff, so simulation is
+     * suggested if you ever need to take more than one.
      *
      * @param player    source of stacks
      * @param predicate item stack filter
@@ -156,8 +161,8 @@ public class InventoryUtility {
      * @param count     let's hope int size is enough...
      * @return amount taken. never negative nor bigger than count...
      */
-    public static Map<ItemStack, Integer> takeFromInventory(
-            EntityPlayerMP player, Predicate<ItemStack> predicate, boolean simulate, int count) {
+    public static Map<ItemStack, Integer> takeFromInventory(EntityPlayerMP player, Predicate<ItemStack> predicate,
+            boolean simulate, int count) {
         ItemStackCounterImpl store = new ItemStackCounterImpl();
         int sum = 0;
         for (InventoryProvider<?> provider : inventoryProviders) {
@@ -168,8 +173,8 @@ public class InventoryUtility {
     }
 
     /**
-     * take count amount of stacks that matches given filter. might take partial amount of stuff, so simulation is suggested
-     * if you ever need to take more than one.
+     * take count amount of stacks that matches given filter. might take partial amount of stuff, so simulation is
+     * suggested if you ever need to take more than one.
      *
      * @param player   source of stacks
      * @param filter   the precise type of item to extract. stackSize matters
@@ -189,14 +194,9 @@ public class InventoryUtility {
     }
 
     // workaround java generics issue
-    private static <R extends Iterable<ItemStack>> int takeFromPlayer(
-            EntityPlayerMP player,
-            Predicate<ItemStack> predicate,
-            boolean simulate,
-            int count,
-            ItemStackCounterImpl store,
-            InventoryProvider<R> provider,
-            ItemStack filter) {
+    private static <R extends Iterable<ItemStack>> int takeFromPlayer(EntityPlayerMP player,
+            Predicate<ItemStack> predicate, boolean simulate, int count, ItemStackCounterImpl store,
+            InventoryProvider<R> provider, ItemStack filter) {
         R inv = provider.getInventory(player);
         if (inv == null) return 0;
         int taken = takeFromInventory(inv, predicate, simulate, count, store, filter, player, true);
@@ -215,29 +215,23 @@ public class InventoryUtility {
      * @param recursive do recursive lookup using {@link #getStackExtractors() stack extractors}
      * @return amount taken. never negative nor bigger than count...
      */
-    public static Map<ItemStack, Integer> takeFromInventory(
-            Iterable<ItemStack> inv, Predicate<ItemStack> predicate, boolean simulate, int count, boolean recursive) {
+    public static Map<ItemStack, Integer> takeFromInventory(Iterable<ItemStack> inv, Predicate<ItemStack> predicate,
+            boolean simulate, int count, boolean recursive) {
         ItemStackCounterImpl store = new ItemStackCounterImpl();
         takeFromInventory(inv, predicate, simulate, count, store, null, null, recursive);
         return store.getStore();
     }
 
-    private static int takeFromInventory(
-            @Nonnull Iterable<ItemStack> inv,
-            @Nonnull Predicate<ItemStack> predicate,
-            boolean simulate,
-            int count,
-            @Nonnull ItemStackCounter store,
-            @Nullable ItemStack filter,
-            @Nullable EntityPlayerMP player,
-            boolean recursive) {
+    private static int takeFromInventory(@Nonnull Iterable<ItemStack> inv, @Nonnull Predicate<ItemStack> predicate,
+            boolean simulate, int count, @Nonnull ItemStackCounter store, @Nullable ItemStack filter,
+            @Nullable EntityPlayerMP player, boolean recursive) {
         int found = 0;
         ItemStack copiedFilter = null;
         if (filter != null) {
             copiedFilter = new ItemStack(filter.getItem(), filter.stackSize, Items.feather.getDamage(filter));
             copiedFilter.setTagCompound(filter.stackTagCompound);
         }
-        for (Iterator<ItemStack> iterator = inv.iterator(); iterator.hasNext(); ) {
+        for (Iterator<ItemStack> iterator = inv.iterator(); iterator.hasNext();) {
             ItemStack stack = iterator.next();
             // invalid stack
             if (stack == null || stack.getItem() == null || stack.stackSize <= 0) continue;
@@ -272,9 +266,10 @@ public class InventoryUtility {
     }
 
     public interface OptimizedExtractor {
+
         /**
-         * Extract a particular type of item. The extractor can choose to not return all items contained within this item
-         * as long as it makes sense, but the author should inform the player of this.
+         * Extract a particular type of item. The extractor can choose to not return all items contained within this
+         * item as long as it makes sense, but the author should inform the player of this.
          * <p>
          * Whether optimized extractor do recursive extraction is at the discretion of implementor.
          *
@@ -288,12 +283,14 @@ public class InventoryUtility {
     }
 
     public interface InventoryProvider<R extends Iterable<ItemStack>> {
+
         R getInventory(EntityPlayerMP player);
 
         void markDirty(R inv);
     }
 
     public interface ItemStackExtractor {
+
         enum APIType {
             MAIN,
             EXTRACT_ONE_STACK,
@@ -302,13 +299,13 @@ public class InventoryUtility {
         boolean isAPIImplemented(APIType type);
 
         /**
-         * Extract a particular type of item. The extractor can choose to not return all items contained within this item
-         * as long as it makes sense, but the author should inform the player of this.
+         * Extract a particular type of item. The extractor can choose to not return all items contained within this
+         * item as long as it makes sense, but the author should inform the player of this.
          * <p>
          * Whether this method does recursive extraction is at the discretion of implementor.
          *
-         * @param predicate the main filtering predicate. never null. It's assumed predicate always returns true on filter,
-         *                  if that is not null
+         * @param predicate the main filtering predicate. never null. It's assumed predicate always returns true on
+         *                  filter, if that is not null
          * @param store     where to store extracted items. Should increment the
          * @param source    from where an extraction should be attempted
          * @param filter    stack to extract. should not be mutated! match the NBT tag using EXACT mode. might be null.
@@ -316,18 +313,12 @@ public class InventoryUtility {
          * @param player    executor of extraction, or null if from a machine
          * @return amount extracted, or -1 if this is not implemented
          */
-        int takeFromStack(
-                Predicate<ItemStack> predicate,
-                boolean simulate,
-                int count,
-                ItemStackCounter store,
-                ItemStack source,
-                ItemStack filter,
-                EntityPlayerMP player);
+        int takeFromStack(Predicate<ItemStack> predicate, boolean simulate, int count, ItemStackCounter store,
+                ItemStack source, ItemStack filter, EntityPlayerMP player);
 
         /**
-         * Extract a particular type of item. The extractor can choose to not return all items contained within this item
-         * as long as it makes sense, but the author should inform the player of this.
+         * Extract a particular type of item. The extractor can choose to not return all items contained within this
+         * item as long as it makes sense, but the author should inform the player of this.
          * <p>
          * Whether this method does recursive extraction is at the discretion of implementor.
          *
@@ -343,20 +334,15 @@ public class InventoryUtility {
 
         static ItemStackExtractor createOnlyOptimized(@Nonnull OptimizedExtractor optimizedExtractor) {
             return new ItemStackExtractor() {
+
                 @Override
                 public boolean isAPIImplemented(APIType type) {
                     return type == APIType.EXTRACT_ONE_STACK;
                 }
 
                 @Override
-                public int takeFromStack(
-                        Predicate<ItemStack> predicate,
-                        boolean simulate,
-                        int count,
-                        ItemStackCounter store,
-                        ItemStack stack,
-                        ItemStack filter,
-                        EntityPlayerMP player) {
+                public int takeFromStack(Predicate<ItemStack> predicate, boolean simulate, int count,
+                        ItemStackCounter store, ItemStack stack, ItemStack filter, EntityPlayerMP player) {
                     return 0;
                 }
 
@@ -369,6 +355,7 @@ public class InventoryUtility {
     }
 
     public interface ItemStackCounter {
+
         /**
          * Add some amount of stack. Note stackSize is used instead of stack.stackSize.
          */
@@ -376,6 +363,7 @@ public class InventoryUtility {
     }
 
     private static class ItemStackCounterImpl implements ItemStackCounter {
+
         private final Map<ItemStack, Integer> store = new ItemStackMap<>(true);
 
         @Override

src/main/java/com/gtnewhorizon/structurelib/util/ItemStackArrayIterable.java

@@ -1,9 +1,11 @@
 package com.gtnewhorizon.structurelib.util;
 
 import java.util.Iterator;
+
 import net.minecraft.item.ItemStack;
 
 public class ItemStackArrayIterable implements Iterable<ItemStack> {
+
     private final ItemStack[] stacks;
 
     public ItemStackArrayIterable(ItemStack[] stacks) {
@@ -17,6 +19,7 @@ public class ItemStackArrayIterable implements Iterable<ItemStack> {
     @Override
     public Iterator<ItemStack> iterator() {
         return new Iterator<ItemStack>() {
+
             private int ptr = 0;
 
             @Override

src/main/java/com/gtnewhorizon/structurelib/util/ItemStackPredicate.java

@@ -3,6 +3,7 @@ package com.gtnewhorizon.structurelib.util;
 import java.util.Objects;
 import java.util.function.BiPredicate;
 import java.util.function.Predicate;
+
 import net.minecraft.block.Block;
 import net.minecraft.init.Items;
 import net.minecraft.item.Item;
@@ -11,6 +12,7 @@ import net.minecraft.nbt.NBTBase;
 import net.minecraft.nbt.NBTTagCompound;
 
 public final class ItemStackPredicate implements Predicate<ItemStack> {
+
     public static ItemStackPredicate from(Item item) {
         return new ItemStackPredicate(item);
     }
@@ -20,8 +22,7 @@ public final class ItemStackPredicate implements Predicate<ItemStack> {
     }
 
     public static ItemStackPredicate from(ItemStack itemStack, NBTMode mode) {
-        return new ItemStackPredicate(itemStack.getItem())
-                .setMeta(Items.feather.getDamage(itemStack))
+        return new ItemStackPredicate(itemStack.getItem()).setMeta(Items.feather.getDamage(itemStack))
                 .setTag(mode, itemStack.stackTagCompound);
     }
 
@@ -63,13 +64,16 @@ public final class ItemStackPredicate implements Predicate<ItemStack> {
     }
 
     public enum NBTMode implements BiPredicate<NBTTagCompound, NBTTagCompound> {
+
         IGNORE {
+
             @Override
             public boolean test(NBTTagCompound lhs, NBTTagCompound rhs) {
                 return true;
             }
         },
         IN {
+
             @Override
             public boolean test(NBTTagCompound lhs, NBTTagCompound rhs) {
                 if (lhs == null || lhs.hasNoTags()) return true;
@@ -87,6 +91,7 @@ public final class ItemStackPredicate implements Predicate<ItemStack> {
             }
         },
         EXACT {
+
             @Override
             public boolean test(NBTTagCompound lhs, NBTTagCompound rhs) {
                 if (lhs != null && lhs.hasNoTags()) lhs = null;
@@ -95,6 +100,7 @@ public final class ItemStackPredicate implements Predicate<ItemStack> {
             }
         },
         IGNORE_KNOWN_INSIGNIFICANT_TAGS {
+
             @Override
             public boolean test(NBTTagCompound lhs, NBTTagCompound rhs) {
                 // fast path for empty tags
@@ -105,8 +111,8 @@ public final class ItemStackPredicate implements Predicate<ItemStack> {
                 return EXACT.test(lhs, rhs);
             }
         };
-        private static final String[] KNOWN_INSIGNIFICANT_TAGS = {
-            "display", // TODO expand/refine this
+
+        private static final String[] KNOWN_INSIGNIFICANT_TAGS = { "display", // TODO expand/refine this
         };
     }
 }

src/main/java/com/gtnewhorizon/structurelib/util/MiscUtils.java

@@ -1,12 +1,14 @@
 package com.gtnewhorizon.structurelib.util;
 
 import java.util.Set;
+
 import net.minecraft.nbt.NBTTagCompound;
 
 /**
  * not related to a certain mod!
  */
 public class MiscUtils {
+
     private MiscUtils() {}
 
     @SuppressWarnings("unchecked")

src/main/java/com/gtnewhorizon/structurelib/util/SortedRegistry.java

@@ -4,6 +4,7 @@ import java.util.*;
 import java.util.function.Consumer;
 
 public class SortedRegistry<V> implements Iterable<V> {
+
     private final NavigableMap<String, V> store = new TreeMap<>();
     /**
      * Store stuff in an array for faster iteration access than a red black tree

src/main/java/com/gtnewhorizon/structurelib/util/Vec3Impl.java

@@ -1,14 +1,28 @@
 package com.gtnewhorizon.structurelib.util;
 
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Function;
+
 import net.minecraft.dispenser.IPosition;
 import net.minecraftforge.common.util.ForgeDirection;
 
 public class Vec3Impl implements Comparable<Vec3Impl> {
+
     public static final Vec3Impl NULL_VECTOR = new Vec3Impl(0, 0, 0);
+    private static final Map<Vec3Impl, Vec3Impl> pool = new HashMap<>();
     private final int val0;
     private final int val1;
     private final int val2;
 
+    /**
+     * THIS WILL CAUSE THIS VECTOR TO PERMANENTLY RESIDE IN STATIC MEMORY. DO NOT USE THIS UNLESS YOU KNOW WHAT YOU ARE
+     * DOING!!!
+     */
+    public static Vec3Impl getFromPool(int in0, int in1, int in2) {
+        return pool.computeIfAbsent(new Vec3Impl(in0, in1, in2), Function.identity());
+    }
+
     public Vec3Impl(int in0, int in1, int in2) {
         this.val0 = in0;
         this.val1 = in1;
@@ -57,8 +71,7 @@ public class Vec3Impl implements Comparable<Vec3Impl> {
     }
 
     public Vec3Impl offset(ForgeDirection facing, int n) {
-        return n == 0
-                ? this
+        return n == 0 ? this
                 : new Vec3Impl(val0 + facing.offsetX * n, val1 + facing.offsetY * n, val2 + facing.offsetZ * n);
     }
 

src/main/java/com/gtnewhorizon/structurelib/util/XSTR.java

@@ -1,37 +1,20 @@
 package com.gtnewhorizon.structurelib.util;
 /*
- A subclass of java.util.random that implements the Xorshift random number
- generator
- <p>
- - it is 30% faster than the generator from Java's library - it produces
- random sequences of higher quality than java.util.Random - this class also
- provides a clone() function
- <p>
- Usage: XSRandom rand = new XSRandom(); //Instantiation x = rand.nextInt();
- //pull a random number
- <p>
- To use the class in legacy code, you may also instantiate an XSRandom object
- and assign it to a java.util.Random object: java.util.Random rand = new
- XSRandom();
- <p>
- for an explanation of the algorithm, see
- http://demesos.blogspot.com/2011/09/pseudo-random-number-generators.html
-
- @author Wilfried Elmenreich University of Klagenfurt/Lakeside Labs
-* http://www.elmenreich.tk
-* <p>
-* This code is released under the GNU Lesser General Public License Version 3
-* http://www.gnu.org/licenses/lgpl-3.0.txt
-*/
+ * A subclass of java.util.random that implements the Xorshift random number generator <p> - it is 30% faster than the
+ * generator from Java's library - it produces random sequences of higher quality than java.util.Random - this class
+ * also provides a clone() function <p> Usage: XSRandom rand = new XSRandom(); //Instantiation x = rand.nextInt();
+ * //pull a random number <p> To use the class in legacy code, you may also instantiate an XSRandom object and assign it
+ * to a java.util.Random object: java.util.Random rand = new XSRandom(); <p> for an explanation of the algorithm, see
+ * http://demesos.blogspot.com/2011/09/pseudo-random-number-generators.html
+ * @author Wilfried Elmenreich University of Klagenfurt/Lakeside Labs http://www.elmenreich.tk <p> This code is released
+ * under the GNU Lesser General Public License Version 3 http://www.gnu.org/licenses/lgpl-3.0.txt
+ */
 
 import java.util.Random;
 import java.util.concurrent.atomic.AtomicLong;
 
 /**
- * XSTR - Xorshift ThermiteRandom
- * Modified by Bogdan-G
- * 03.06.2016
- * version 0.0.4
+ * XSTR - Xorshift ThermiteRandom Modified by Bogdan-G 03.06.2016 version 0.0.4
  */
 public class XSTR extends Random {
 
@@ -40,10 +23,11 @@ public class XSTR extends Random {
     private static final long GAMMA = 0x9e3779b97f4a7c15L;
     private static final int PROBE_INCREMENT = 0x9e3779b9;
     private static final long SEEDER_INCREMENT = 0xbb67ae8584caa73bL;
-    private static final double DOUBLE_UNIT = 0x1.0p-53; // 1.0  / (1L << 53)
+    private static final double DOUBLE_UNIT = 0x1.0p-53; // 1.0 / (1L << 53)
     private static final float FLOAT_UNIT = 0x1.0p-24f; // 1.0f / (1 << 24)
     private static final AtomicLong seedUniquifier = new AtomicLong(8682522807148012L);
     public static final XSTR XSTR_INSTANCE = new XSTR() {
+
         @Override
         public synchronized void setSeed(long seed) {
             if (!Thread.currentThread().getStackTrace()[2].getClassName().equals(Random.class.getName())) {
@@ -53,13 +37,11 @@ public class XSTR extends Random {
     };
 
     /*
-    MODIFIED BY: Robotia
-    Modification: Implemented Random class seed generator
-    */
+     * MODIFIED BY: Robotia Modification: Implemented Random class seed generator
+     */
 
     /**
-     * Creates a new pseudo random number generator. The seed is initialized to
-     * the current time, as if by
+     * Creates a new pseudo random number generator. The seed is initialized to the current time, as if by
      * <code>setSeed(System.currentTimeMillis());</code>.
      */
     public XSTR() {
@@ -79,8 +61,8 @@ public class XSTR extends Random {
     }
 
     /**
-     * Creates a new pseudo random number generator, starting with the specified
-     * seed, using <code>setSeed(seed);</code>.
+     * Creates a new pseudo random number generator, starting with the specified seed, using
+     * <code>setSeed(seed);</code>.
      *
      * @param seed the initial seed
      */
@@ -108,9 +90,8 @@ public class XSTR extends Random {
     }
 
     /**
-     * Sets the seed for this pseudo random number generator. As described
-     * above, two instances of the same random class, starting with the same
-     * seed, produce the same results, if the same methods are called.
+     * Sets the seed for this pseudo random number generator. As described above, two instances of the same random
+     * class, starting with the same seed, produce the same results, if the same methods are called.
      *
      * @param seed the new seed
      */
@@ -128,9 +109,8 @@ public class XSTR extends Random {
     }
 
     /**
-     * Implementation of George Marsaglia's elegant Xorshift random generator
-     * 30% faster and better quality than the built-in java.util.random see also
-     * see http://www.javamex.com/tutorials/random_numbers/xorshift.shtml
+     * Implementation of George Marsaglia's elegant Xorshift random generator 30% faster and better quality than the
+     * built-in java.util.random see also see http://www.javamex.com/tutorials/random_numbers/xorshift.shtml
      *
      * @param nbits will shift nbits bits
      * @return next seed
@@ -170,15 +150,14 @@ public class XSTR extends Random {
     }
 
     /**
-     * Returns a pseudorandom, uniformly distributed {@code int} value between 0
-     * (inclusive) and the specified value (exclusive), drawn from this random
-     * number generator's sequence. The general contract of {@code nextInt} is
-     * that one {@code int} value in the specified range is pseudorandomly
-     * generated and returned. All {@code bound} possible {@code int} values are
-     * produced with (approximately) equal probability. The method
-     * {@code nextInt(int bound)} is implemented by class {@code Random} as if
-     * by:
-     * <pre> {@code
+     * Returns a pseudorandom, uniformly distributed {@code int} value between 0 (inclusive) and the specified value
+     * (exclusive), drawn from this random number generator's sequence. The general contract of {@code nextInt} is that
+     * one {@code int} value in the specified range is pseudorandomly generated and returned. All {@code bound} possible
+     * {@code int} values are produced with (approximately) equal probability. The method {@code nextInt(int bound)} is
+     * implemented by class {@code Random} as if by:
+     * 
+     * <pre>
+     *  {@code
      * public int nextInt(int bound) {
      *   if (bound <= 0)
      *     throw new IllegalArgumentException("bound must be positive");
@@ -192,35 +171,29 @@ public class XSTR extends Random {
      *       val = bits % bound;
      *   } while (bits - val + (bound-1) < 0);
      *   return val;
-     * }}</pre>
+     * }}
+     * </pre>
      *
-     * <p>The hedge "approx
-     * imately" is used in the foregoing description only because the next
-     * method is only approximately an unbiased source of independently chosen
-     * bits. If it were a perfect source of randomly chosen bits, then the
-     * algorithm shown would choose {@code int} values from the stated range
-     * with perfect uniformity.
      * <p>
-     * The algorithm is slightly tricky. It rejects values that would result in
-     * an uneven distribution (due to the fact that 2^31 is not divisible by n).
-     * The probability of a value being rejected depends on n. The worst case is
-     * n=2^30+1, for which the probability of a reject is 1/2, and the expected
-     * number of iterations before the loop terminates is 2.
+     * The hedge "approx imately" is used in the foregoing description only because the next method is only
+     * approximately an unbiased source of independently chosen bits. If it were a perfect source of randomly chosen
+     * bits, then the algorithm shown would choose {@code int} values from the stated range with perfect uniformity.
      * <p>
-     * The algorithm treats the case where n is a power of two specially: it
-     * returns the correct number of high-order bits from the underlying
-     * pseudo-random number generator. In the absence of special treatment, the
-     * correct number of <i>low-order</i> bits would be returned. Linear
-     * congruential pseudo-random number generators such as the one implemented
-     * by this class are known to have short periods in the sequence of values
-     * of their low-order bits. Thus, this special case greatly increases the
-     * length of the sequence of values returned by successive calls to this
-     * method if n is a small power of two.
+     * The algorithm is slightly tricky. It rejects values that would result in an uneven distribution (due to the fact
+     * that 2^31 is not divisible by n). The probability of a value being rejected depends on n. The worst case is
+     * n=2^30+1, for which the probability of a reject is 1/2, and the expected number of iterations before the loop
+     * terminates is 2.
+     * <p>
+     * The algorithm treats the case where n is a power of two specially: it returns the correct number of high-order
+     * bits from the underlying pseudo-random number generator. In the absence of special treatment, the correct number
+     * of <i>low-order</i> bits would be returned. Linear congruential pseudo-random number generators such as the one
+     * implemented by this class are known to have short periods in the sequence of values of their low-order bits.
+     * Thus, this special case greatly increases the length of the sequence of values returned by successive calls to
+     * this method if n is a small power of two.
      *
      * @param bound the upper bound (exclusive). Must be positive.
-     * @return the next pseudorandom, uniformly distributed {@code int} value
-     * between zero (inclusive) and {@code bound} (exclusive) from this random
-     * number generator's sequence
+     * @return the next pseudorandom, uniformly distributed {@code int} value between zero (inclusive) and {@code bound}
+     *         (exclusive) from this random number generator's sequence
      * @throws IllegalArgumentException if bound is not positive
      * @since 1.2
      */
@@ -230,18 +203,10 @@ public class XSTR extends Random {
         // throw new RuntimeException("BadBound");
         // }
 
-        /*int r = next(31);
-        int m = bound - 1;
-        if ((bound & m) == 0) // i.e., bound is a power of 2
-        {
-            r = (int) ((bound * (long) r) >> 31);
-        } else {
-            for (int u = r;
-                    u - (r = u % bound) + m < 0;
-                    u = next(31))
-                ;
-        }
-        return r;*/
+        /*
+         * int r = next(31); int m = bound - 1; if ((bound & m) == 0) // i.e., bound is a power of 2 { r = (int) ((bound
+         * * (long) r) >> 31); } else { for (int u = r; u - (r = u % bound) + m < 0; u = next(31)) ; } return r;
+         */
         // speedup, new nextInt ~+40%
         long last = seed ^ seed << 21;
         last ^= last >>> 35;
@@ -269,10 +234,9 @@ public class XSTR extends Random {
 
     @Override
     public void nextBytes(byte[] bytes_arr) {
-        for (int iba = 0, lenba = bytes_arr.length; iba < lenba; ) {
-            for (int rndba = nextInt(), nba = Math.min(lenba - iba, Integer.SIZE / Byte.SIZE);
-                    nba-- > 0;
-                    rndba >>= Byte.SIZE) {
+        for (int iba = 0, lenba = bytes_arr.length; iba < lenba;) {
+            for (int rndba = nextInt(), nba = Math.min(lenba - iba, Integer.SIZE / Byte.SIZE); nba--
+                    > 0; rndba >>= Byte.SIZE) {
                 bytes_arr[iba++] = (byte) rndba;
             }
         }

src/main/javadoc/overview.html

@@ -1,4 +1,4 @@
-<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
+<!DOCTYPE html>
 <HTML>
 <HEAD>
     <TITLE>API Overview</TITLE>
@@ -97,6 +97,18 @@ StructureLib API documentation.
     breaking client code.
 </p>
 
+<h2>{@link com.gtnewhorizon.structurelib.StructureEvent}</h2>
+<p>
+    This class is the base class of all events that will be posted while a IStructureDefinition are visited.
+    These events are disabled by default, and can be enabled by calling {@link com.gtnewhorizon.structurelib.StructureLibAPI#enableInstrument(Object)}.
+    To receive these events, register an event handler to {@link net.minecraftforge.common.MinecraftForge#EVENT_BUS}.
+    Handlers should filter the events received by {@link com.gtnewhorizon.structurelib.StructureEvent#getInstrumentIdentifier()}.
+</p>
+<p>
+    <b>These events are intended for third party tools to inspect structure details.</b> Normal users should not use
+    these at all.
+</p>
+
 <h1>Important Concepts</h1>
 <h2>Context Object</h2>
 <p>
@@ -207,9 +219,9 @@ whereas all these structure elements are designed without considering channels w
 <pre>
 import com.gtnewhorizon.structurelib.structure.IStructureElement;
 
-public class MyHatchElement&lt;T> implements IStructureElement&lt;T> {
+public class MyHatchElement&lt;T&gt; implements IStructureElement&lt;T&gt; {
     //...
-    @Override
+   {@literal @}Override
     public PlaceResult survivalPlaceBlock(
             Object o,
             World world,
@@ -231,5 +243,13 @@ public class MyHatchElement&lt;T> implements IStructureElement&lt;T> {
 
 The code for placeBlock() and spawnHint() will be left as an exercise for the reader.
 
+<h2>Instrumenting StructureLib</h2>
+<p>
+    StructureLib support third party tools to poke into structure's internals via events. This is done by listening to {@link com.gtnewhorizon.structurelib.StructureEvent}
+    and its subclasses on the {@link net.minecraftforge.common.MinecraftForge#EVENT_BUS forge main event bus}.
+</p>
+<p>
+    Please refer to {@link com.gtnewhorizon.structurelib.StructureEvent} to see what events are available.
+</p>
 </BODY>
 </HTML>

src/main/resources/assets/structurelib/lang/zh_CN.lang

@@ -28,7 +28,7 @@ item.structurelib.constructableTrigger.desc.3= (潜行右键可以直接完成
 item.structurelib.constructableTrigger.desc.4=此物品堆叠数量会影响显示的机器等级/模式/类型
 item.structurelib.constructableTrigger.desc.5=按下 §l[左SHIFT]§r 以显示子信道
 item.structurelib.constructableTrigger.desc.lshift.0=包含 %d 个子信道
-item.structurelib.constructableTrigger.too_fast=请在下一次自动搭建前等待%d毫秒...
+item.structurelib.constructableTrigger.too_fast=请在下一次自动搭建前等待 %d 毫秒...
 item.structurelib.constructableTrigger.gui.key=信道名:
 item.structurelib.constructableTrigger.gui.value=值:
 item.structurelib.constructableTrigger.gui.add=添加
@@ -39,8 +39,9 @@ item.structurelib.constructableTrigger.gui.wipe=§4全部清空
 structurelib.autoplace.built_stat=已放置 %s 个方块
 structurelib.autoplace.complete=§a这个多方块结构已经完成自动搭建！
 structurelib.autoplace.error.not_enabled=§c这个多方块结构不支持在生存模式下自动搭建！
-structurelib.autoplace.error.no_simple_block=§c建议放置§r%s§c，但没有找到它
-structurelib.autoplace.error.no_item_stack=§c建议使用§r%s§c放置方块，但没有找到它
+structurelib.autoplace.error.no_simple_block=§c建议放置 §r%s§c ，但没有找到它
+structurelib.autoplace.error.no_item_stack=§c建议使用 §r%s§c 放置方块，但没有找到它
+structurelib.autoplace.warning.no_explicit_channel=§6这个结构依赖于不存在的子信道 §r%s§6 。已使用主信道值替代。
 
 structurelib.blockhint.desc.0=帮助你搭建机器
 structurelib.blockhint.0.name=提示方块：1号

src/test/java/com/gtnewhorizon/structurelib/alignment/enumerable/ExtendedFacingTest.java

@@ -0,0 +1,29 @@
+package com.gtnewhorizon.structurelib.alignment.enumerable;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import net.minecraftforge.common.util.ForgeDirection;
+
+import org.junit.jupiter.api.Test;
+
+class ExtendedFacingTest {
+
+    @Test
+    void ensureGetWorldDirectionDoesNotCrashNorReturnNull() {
+        for (ExtendedFacing ef : ExtendedFacing.VALUES) {
+            for (ForgeDirection src : ForgeDirection.VALID_DIRECTIONS) {
+                assertNotNull(ef.getWorldDirection(src));
+            }
+        }
+    }
+
+    @Test
+    void ensureGetWorldDirectionIsCorrect() {
+        assertEquals(ForgeDirection.DOWN, ExtendedFacing.EAST_NORMAL_NONE.getWorldDirection(ForgeDirection.UP));
+        assertEquals(ForgeDirection.DOWN, ExtendedFacing.NORTH_NORMAL_NONE.getWorldDirection(ForgeDirection.UP));
+        assertEquals(ForgeDirection.NORTH, ExtendedFacing.NORTH_NORMAL_NONE.getWorldDirection(ForgeDirection.NORTH));
+        assertEquals(ForgeDirection.NORTH, ExtendedFacing.NORTH_CLOCKWISE_NONE.getWorldDirection(ForgeDirection.NORTH));
+        assertEquals(ForgeDirection.DOWN, ExtendedFacing.NORTH_CLOCKWISE_NONE.getWorldDirection(ForgeDirection.EAST));
+    }
+}