New ITeleporter interface making dimensional teleportation easier. (#4602)

src/main/java/net/minecraftforge/common/util/FakePlayer.java

@@ -52,6 +52,6 @@ public class FakePlayer extends EntityPlayerMP
     @Override public boolean canAttackPlayer(EntityPlayer player){ return false; }
     @Override public void onDeath(DamageSource source){ return; }
     @Override public void onUpdate(){ return; }
-    @Override public Entity changeDimension(int dim){ return this; }
+    @Override public Entity changeDimension(int dim, ITeleporter teleporter){ return this; }
     @Override public void handleClientSettings(CPacketClientSettings pkt){ return; }
 }

src/main/java/net/minecraftforge/common/util/ITeleporter.java

@@ -0,0 +1,60 @@
+/*
+ * Minecraft Forge
+ * Copyright (c) 2017.
+ *
+ * This library 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 version 2.1
+ * of the License.
+ *
+ * This library 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.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+package net.minecraftforge.common.util;
+
+import net.minecraft.entity.Entity;
+import net.minecraft.world.Teleporter;
+import net.minecraft.world.World;
+import net.minecraft.world.WorldProvider;
+
+/**
+ * Interface for handling the placement of entities during dimension change.
+ *
+ * An implementation of this interface can be used to place the entity
+ * in a safe location, or generate a return portal, for instance.
+ *
+ * See the {@link net.minecraft.world.Teleporter} class, which has
+ * been patched to implement this interface, for a vanilla example.
+ */
+public interface ITeleporter
+{
+    /**
+     * Called to handle placing the entity in the new world.
+     *
+     * The initial position of the entity will be its
+     * position in the origin world, multiplied horizontally
+     * by the computed cross-dimensional movement factor
+     * (see {@link WorldProvider#getMovementFactor()}).
+     *
+     * Note that the supplied entity has not yet been spawned
+     * in the destination world at the time.
+     *
+     * @param world  the entity's destination
+     * @param entity the entity to be placed
+     * @param yaw    the suggested yaw value to apply
+     */
+    void placeEntity(World world, Entity entity, float yaw);
+
+    // used internally to handle vanilla hardcoding
+    default boolean isVanilla()
+    {
+        return getClass() == Teleporter.class;
+    }
+}

src/main/java/net/minecraftforge/server/command/CommandSetDimension.java

@@ -0,0 +1,120 @@
+/*
+ * Minecraft Forge
+ * Copyright (c) 2017.
+ *
+ * This library 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 version 2.1
+ * of the License.
+ *
+ * This library 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.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+package net.minecraftforge.server.command;
+
+import net.minecraft.command.CommandBase;
+import net.minecraft.command.CommandException;
+import net.minecraft.command.ICommandSender;
+import net.minecraft.command.WrongUsageException;
+import net.minecraft.entity.Entity;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.world.World;
+import net.minecraftforge.common.DimensionManager;
+import net.minecraftforge.common.util.ITeleporter;
+
+import javax.annotation.Nullable;
+import java.util.Collections;
+import java.util.List;
+
+public class CommandSetDimension extends CommandBase
+{
+    @Override
+    public String getName()
+    {
+        return "setdimension";
+    }
+
+    @Override
+    public List<String> getAliases()
+    {
+        return Collections.singletonList("setdim");
+    }
+
+    @Override
+    public String getUsage(ICommandSender sender)
+    {
+        return "commands.forge.setdim.usage";
+    }
+
+    @Override
+    public List<String> getTabCompletions(MinecraftServer server, ICommandSender sender, String[] args, @Nullable BlockPos targetPos)
+    {
+        if (args.length > 2 && args.length <= 5)
+        {
+            return getTabCompletionCoordinate(args, 2, targetPos);
+        }
+        return Collections.emptyList();
+    }
+
+    @Override
+    public int getRequiredPermissionLevel()
+    {
+        return 2;
+    }
+
+    @Override
+    public void execute(MinecraftServer server, ICommandSender sender, String[] args) throws CommandException
+    {
+        // args: <entity> <dim> [<x> <y> <z>]
+        if (args.length != 2 && args.length != 5)
+        {
+            throw new WrongUsageException("commands.forge.setdim.usage");
+        }
+        Entity entity = getEntity(server, sender, args[0]);
+        if (!checkEntity(entity))
+        {
+            throw new CommandException("commands.forge.setdim.invalid.entity", entity.getName());
+        }
+        int dimension = parseInt(args[1]);
+        if (!DimensionManager.isDimensionRegistered(dimension))
+        {
+            throw new CommandException("commands.forge.setdim.invalid.dim", dimension);
+        }
+        if (dimension == entity.dimension)
+        {
+            throw new CommandException("commands.forge.setdim.invalid.nochange", entity.getName(), dimension);
+        }
+        BlockPos pos = args.length == 5 ? parseBlockPos(sender, args, 2, false) : sender.getPosition();
+        entity.changeDimension(dimension, new CommandTeleporter(pos));
+    }
+
+    private static boolean checkEntity(Entity entity)
+    {
+        // use vanilla portal logic, try to avoid doing anything too silly
+        return !entity.isRiding() && !entity.isBeingRidden() && entity.isNonBoss();
+    }
+
+    private static class CommandTeleporter implements ITeleporter
+    {
+        private final BlockPos targetPos;
+
+        private CommandTeleporter(BlockPos targetPos)
+        {
+            this.targetPos = targetPos;
+        }
+
+        @Override
+        public void placeEntity(World world, Entity entity, float yaw)
+        {
+            entity.moveToBlockPosAndAngles(targetPos, yaw, entity.rotationPitch);
+        }
+    }
+}

src/main/java/net/minecraftforge/server/command/ForgeCommand.java

@@ -32,6 +32,7 @@ public class ForgeCommand extends CommandTreeBase
         super.addSubcommand(new CommandTrack());
         super.addSubcommand(new CommandGenerate());
         super.addSubcommand(new CommandEntity());
+        super.addSubcommand(new CommandSetDimension());
         super.addSubcommand(new CommandTreeHelp(this));
     }