Add ability for Items to create custom Entities for themselves when added to the world, PR: #151

common/net/minecraftforge/common/ForgeInternalHandler.java

@@ -0,0 +1,28 @@
+package net.minecraftforge.common;
+
+import net.minecraft.src.*;
+import net.minecraftforge.event.*;
+import net.minecraftforge.event.entity.*;
+
+public class ForgeInternalHandler
+{
+    @ForgeSubscribe(priority = EventPriority.HIGHEST)
+    public void onEntityJoinWorld(EntityJoinWorldEvent event)
+    {
+        Entity entity = event.entity;
+        if (entity instanceof EntityItem)
+        {
+            ItemStack item = ((EntityItem)entity).item;
+            if (item.getItem().hasCustomEntity(item))
+            {
+                Entity newEntity = item.getItem().createEntity(event.world, entity, item);
+                if (newEntity != null)
+                {
+                    entity.setDead();
+                    event.setCanceled(true);
+                    event.world.spawnEntityInWorld(entity);
+                }
+            }
+        }
+    }
+}

common/net/minecraftforge/common/MinecraftForge.java

@@ -3,6 +3,8 @@ package net.minecraftforge.common;
 import java.lang.reflect.Constructor;
 import java.util.*;
 
+import cpw.mods.fml.common.FMLLog;
+
 import net.minecraft.src.*;
 import net.minecraftforge.common.ForgeHooks.GrassEntry;
 import net.minecraftforge.common.ForgeHooks.SeedEntry;
@@ -19,6 +21,7 @@ public class MinecraftForge
      */
     public static final EventBus EVENT_BUS = new EventBus();
     public static boolean SPAWNER_ALLOW_ON_INVERTED = false;
+    private static final ForgeInternalHandler INTERNAL_HANDLER = new ForgeInternalHandler();
     
     
     /** Register a new plant to be planted when bonemeal is used on grass.
@@ -166,6 +169,9 @@ public class MinecraftForge
     */
    public static void initialize()
    {
+       System.out.printf("MinecraftForge v%s Initialized\n", ForgeVersion.getVersion());
+       FMLLog.info("MinecraftForge v%s Initialized", ForgeVersion.getVersion());
+
        Block filler = new Block(0, Material.air);
        Block.blocksList[0] = null;
        Block.opaqueCubeLookup[0] = false;
@@ -185,6 +191,8 @@ public class MinecraftForge
            temp[x] = EntityEnderman.carriableBlocks[x];
        }
        EntityEnderman.carriableBlocks = temp;
+
+       EVENT_BUS.register(INTERNAL_HANDLER);
    }
    
    public static String getBrandingVersion()

patches/common/net/minecraft/src/Item.java.patch

@@ -37,7 +37,7 @@
          Vec3 var23 = var13.addVector((double)var18 * var21, (double)var17 * var21, (double)var20 * var21);
          return par1World.rayTraceBlocks_do_do(var13, var23, par3, !par3);
      }
-@@ -650,4 +662,212 @@
+@@ -650,4 +662,240 @@
      {
          StatList.initStats();
      }
@@ -248,5 +248,33 @@
 +    public int getEntityLifespan(ItemStack itemStack, World world)
 +    {
 +        return 6000;
++    }
++
++    /**
++     * Determines if this Item has a special entity for when they are in the world.
++     * Is called when a EntityItem is spawned in the world, if true and Item#createCustomEntity 
++     * returns non null, the EntityItem will be destroyed and the new Entity will be added to the world.
++     * 
++     * @param stack The current item stack
++     * @return True of the item has a custom entity, If true, Item#createCustomEntity will be called
++     */
++    public boolean hasCustomEntity(ItemStack stack)
++    {
++        return false;
++    }
++
++    /**
++     * This function should return a new entity to replace the dropped item.
++     * Returning null here will not kill the EntityItem and will leave it to function normally.
++     * Called when the item it placed in a world.
++     * 
++     * @param world The world object
++     * @param location The EntityItem object, useful for getting the position of the entity
++     * @param itemstack The current item stack
++     * @return A new Entity object to spawn or null
++     */
++    public Entity createEntity(World world, Entity location, ItemStack itemstack)
++    {
++        return null;
 +    }
  }