Added a structure cost preview.

src/main/java/vazkii/botania/api/lexicon/multiblock/Multiblock.java

@@ -13,12 +13,10 @@ package vazkii.botania.api.lexicon.multiblock;
 import java.util.ArrayList;
 import java.util.List;
 
-import vazkii.botania.api.lexicon.multiblock.component.MultiblockComponent;
-
-import com.sun.org.apache.xpath.internal.operations.Mult;
-
 import net.minecraft.block.Block;
+import net.minecraft.item.ItemStack;
 import net.minecraft.util.ChunkCoordinates;
+import vazkii.botania.api.lexicon.multiblock.component.MultiblockComponent;
 
 /**
  * This class describes a Mutiblock object. It's used to display a
@@ -28,6 +26,7 @@ import net.minecraft.util.ChunkCoordinates;
 public class Multiblock {
 	
 	public List<MultiblockComponent> components = new ArrayList();
+	public List<ItemStack> materials = new ArrayList();
 	
 	public int minX, minY, minZ, maxX, maxY, maxZ, offX, offY, offZ;
 	
@@ -38,6 +37,7 @@ public class Multiblock {
 	public void addComponent(MultiblockComponent component) {
 		components.add(component);
 		changeAxisForNewComponent(component.relPos.posX, component.relPos.posY, component.relPos.posZ);
+		calculateCostForNewComponent(component);
 	}
 
 	/**
@@ -65,6 +65,26 @@ public class Multiblock {
 			maxZ = z;
 	}
 	
+	private void calculateCostForNewComponent(MultiblockComponent comp) {
+		ItemStack[] materials = comp.getMaterials();
+		if(materials != null)
+			for(ItemStack stack : materials)
+				addStack(stack);
+	}
+	
+	private void addStack(ItemStack stack) {
+		if(stack == null)
+			return;
+		
+		for(ItemStack oStack : materials)
+			if(oStack.isItemEqual(stack) && ItemStack.areItemStackTagsEqual(oStack, stack)) {
+				oStack.stackSize += stack.stackSize;
+				return;
+			}
+				
+		materials.add(stack);
+	}
+	
 	public void setRenderOffset(int x, int y, int z) {
 		offX = x;
 		offY = y;

src/main/java/vazkii/botania/api/lexicon/multiblock/component/MultiblockComponent.java

@@ -11,10 +11,9 @@
 package vazkii.botania.api.lexicon.multiblock.component;
 
 import net.minecraft.block.Block;
+import net.minecraft.item.ItemStack;
 import net.minecraft.util.ChunkCoordinates;
 import net.minecraft.world.World;
-import cpw.mods.fml.relauncher.Side;
-import cpw.mods.fml.relauncher.SideOnly;
 
 /**
  * A component of a multiblock, the normal one
@@ -48,6 +47,10 @@ public class MultiblockComponent {
 		return world.getBlock(x, y, z) == getBlock() && (meta == -1 || world.getBlockMetadata(x, y, z) == meta);
 	}
 	
+	public ItemStack[] getMaterials() {
+		return new ItemStack[] { new ItemStack(block, 1, meta) };
+	}
+	
 	public void rotate(double angle) {
 		double x = relPos.posX;
 		double z = relPos.posZ;

src/main/java/vazkii/botania/common/lexicon/page/PageMultiblock.java

@@ -10,20 +10,28 @@
  */
 package vazkii.botania.common.lexicon.page;
 
+import java.util.ArrayList;
+import java.util.List;
+
 import net.minecraft.block.Block;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.FontRenderer;
 import net.minecraft.client.gui.GuiButton;
 import net.minecraft.client.gui.GuiScreen;
 import net.minecraft.client.renderer.RenderBlocks;
+import net.minecraft.client.renderer.RenderHelper;
+import net.minecraft.client.renderer.entity.RenderItem;
 import net.minecraft.client.renderer.texture.TextureManager;
 import net.minecraft.client.renderer.texture.TextureMap;
+import net.minecraft.init.Blocks;
+import net.minecraft.item.ItemStack;
 import net.minecraft.util.ChunkCoordinates;
 import net.minecraft.util.EnumChatFormatting;
 import net.minecraft.util.ResourceLocation;
 import net.minecraft.util.StatCollector;
 
 import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL12;
 
 import vazkii.botania.api.internal.IGuiLexiconEntry;
 import vazkii.botania.api.lexicon.LexiconPage;
@@ -67,7 +75,7 @@ public class PageMultiblock extends LexiconPage {
 		
 		final float maxX = 90, maxY = 60;
 		GL11.glPushMatrix();
-		GL11.glTranslatef(gui.getLeft() + gui.getWidth() / 2, gui.getTop() + 90, gui.getZLevel() + 500F);
+		GL11.glTranslatef(gui.getLeft() + gui.getWidth() / 2, gui.getTop() + 90, gui.getZLevel() + 100F);
 
 		float diag = (float) Math.sqrt(mb.getXSize() * mb.getXSize() + mb.getZSize() * mb.getZSize());
 		float height = mb.getYSize();
@@ -91,6 +99,30 @@ public class PageMultiblock extends LexiconPage {
 		font.setUnicodeFlag(true);
 		font.drawString(s, gui.getLeft() + gui.getWidth() / 2 - font.getStringWidth(s) / 2, gui.getTop() + 16, 0x000000);
 		font.setUnicodeFlag(unicode);
+		
+		GL11.glEnable(GL12.GL_RESCALE_NORMAL);
+		RenderHelper.enableGUIStandardItemLighting();
+		int x = gui.getLeft() + 15;
+		int y = gui.getTop() + 25;
+		RenderItem.getInstance().renderItemIntoGUI(font, render, new ItemStack(Blocks.stonebrick), x, y);
+		RenderHelper.disableStandardItemLighting();
+		GL11.glDisable(GL12.GL_RESCALE_NORMAL);
+		
+		GL11.glPushMatrix();
+		GL11.glTranslatef(0F, 0F, 200F);
+		if(mx >= x && mx < x + 16 && my >= y && my < y + 16) {
+			List<String> mats = new ArrayList();
+			mats.add(StatCollector.translateToLocal("botaniamisc.materialsRequired"));
+			for(ItemStack stack : mb.materials) {
+				String size = "" + stack.stackSize;
+				if(size.length() < 2)
+					size = "0" + size;
+				mats.add(" " + EnumChatFormatting.AQUA + size + " " + EnumChatFormatting.GRAY + stack.getDisplayName());
+			}
+				
+			vazkii.botania.client.core.helper.RenderHelper.renderTooltip(mx, my, mats);
+		}
+		GL11.glPopMatrix();
 	}
 
 	public void renderBlock(Block block, int meta, int x, int y, int z) {