Added event hooks to control to allow mod control of mob spawning. PR: #337

Deprecated LivingSpecialSpawnEvent in favor of new LivingSpawnEvent.SpecialSpawn

common/net/minecraftforge/event/ForgeEventFactory.java

@@ -1,12 +1,18 @@
 package net.minecraftforge.event;
 
 import net.minecraft.block.Block;
+import net.minecraft.entity.EntityLiving;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.item.ItemStack;
+import net.minecraft.world.World;
 import net.minecraftforge.common.MinecraftForge;
+import net.minecraftforge.event.Event.Result;
+import net.minecraftforge.event.entity.living.LivingSpawnEvent;
+import net.minecraftforge.event.entity.living.LivingSpecialSpawnEvent;
 import net.minecraftforge.event.entity.player.*;
 import net.minecraftforge.event.entity.player.PlayerInteractEvent.Action;
 
+@SuppressWarnings("deprecation")
 public class ForgeEventFactory
 {
     public static boolean doPlayerHarvestCheck(EntityPlayer player, Block block, boolean success)
@@ -33,4 +39,24 @@ public class ForgeEventFactory
     {
         MinecraftForge.EVENT_BUS.post(new PlayerDestroyItemEvent(player, stack));
     }
+
+    public static Result canEntitySpawn(EntityLiving entity, World world, float x, float y, float z)
+    {
+        LivingSpawnEvent.CheckSpawn event = new LivingSpawnEvent.CheckSpawn(entity, world, x, y, z);
+        MinecraftForge.EVENT_BUS.post(event);
+        return event.getResult();
+    }
+
+    public static boolean doSpecialSpawn(EntityLiving entity, World world, float x, float y, float z)
+    {
+        boolean result = MinecraftForge.EVENT_BUS.post(new LivingSpecialSpawnEvent(entity, world, x, y, z));
+        LivingSpawnEvent.SpecialSpawn nEvent = new LivingSpawnEvent.SpecialSpawn(entity, world, x, y, z);
+
+        if (result) //For the time being, copy the canceled state from the old legacy event
+        {           // Remove when we remove LivingSpecialSpawnEvent.
+            nEvent.setCanceled(true);
+        }
+
+        return MinecraftForge.EVENT_BUS.post(nEvent);
+    }
 }

common/net/minecraftforge/event/entity/living/LivingSpawnEvent.java

@@ -0,0 +1,50 @@
+package net.minecraftforge.event.entity.living;
+
+import net.minecraft.entity.EntityLiving;
+import net.minecraft.world.World;
+import net.minecraftforge.event.Cancelable;
+import net.minecraftforge.event.Event.HasResult;
+
+public class LivingSpawnEvent extends LivingEvent
+{
+    public final World world;
+    public final float x;
+    public final float y;
+    public final float z;
+    
+    public LivingSpawnEvent(EntityLiving entity, World world, float x, float y, float z)
+    {
+        super(entity);
+        this.world = world;
+        this.x = x;
+        this.y = y;
+        this.z = z;
+    }
+
+    /**
+     * Fires before mob spawn events.
+     * 
+     * Result is significant:
+     *    DEFAULT: use vanilla spawn rules
+     *    ALLOW:   allow the spawn
+     *    DENY:    deny the spawn
+     *
+     */
+    @HasResult
+    public static class CheckSpawn extends LivingSpawnEvent
+    {
+        public CheckSpawn(EntityLiving entity, World world, float x, float y, float z)
+        {
+            super(entity, world, x, y, z);
+        }
+    }
+
+    @Cancelable
+    public static class SpecialSpawn extends LivingSpawnEvent
+    {
+        public SpecialSpawn(EntityLiving entity, World world, float x, float y, float z)
+        {
+            super(entity, world, x, y, z);
+        }
+    }
+}

common/net/minecraftforge/event/entity/living/LivingSpecialSpawnEvent.java

@@ -4,6 +4,7 @@ import net.minecraft.entity.EntityLiving;
 import net.minecraft.world.World;
 import net.minecraftforge.event.Cancelable;
 
+@Deprecated //Remove next MC Version
 @Cancelable
 public class LivingSpecialSpawnEvent extends LivingEvent
 {

patches/minecraft/net/minecraft/world/SpawnerAnimals.java.patch

@@ -8,17 +8,19 @@
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
-@@ -19,6 +21,9 @@
+@@ -19,6 +21,11 @@
  import net.minecraft.world.biome.SpawnListEntry;
  import net.minecraft.world.chunk.Chunk;
  
 +import net.minecraftforge.common.MinecraftForge;
++import net.minecraftforge.event.Event.Result;
++import net.minecraftforge.event.ForgeEventFactory;
 +import net.minecraftforge.event.entity.living.LivingSpecialSpawnEvent;
 +
  public final class SpawnerAnimals
  {
      /** The 17x17 area around the player where mobs can spawn */
-@@ -93,6 +98,9 @@
+@@ -93,6 +100,9 @@
                  if ((!var35.getPeacefulCreature() || par2) && (var35.getPeacefulCreature() || par1) && (!var35.getAnimal() || par3) && par0WorldServer.countEntities(var35.getCreatureClass()) <= var35.getMaxNumberOfCreature() * eligibleChunksForSpawning.size() / 256)
                  {
                      Iterator var37 = eligibleChunksForSpawning.keySet().iterator();
@@ -28,7 +30,17 @@
                      label110:
  
                      while (var37.hasNext())
-@@ -221,7 +229,8 @@
+@@ -169,7 +179,8 @@
+ 
+                                                             var39.setLocationAndAngles((double)var24, (double)var25, (double)var26, par0WorldServer.rand.nextFloat() * 360.0F, 0.0F);
+ 
+-                                                            if (var39.getCanSpawnHere())
++                                                            Result canSpawn = ForgeEventFactory.canEntitySpawn(var39, par0WorldServer, var24, var25, var26);
++                                                            if (canSpawn == Result.ALLOW || (canSpawn == Result.DEFAULT && var39.getCanSpawnHere()))
+                                                             {
+                                                                 ++var16;
+                                                                 par0WorldServer.spawnEntityInWorld(var39);
+@@ -221,7 +232,8 @@
          else
          {
              int var5 = par1World.getBlockId(par2, par3 - 1, par4);
@@ -38,11 +50,11 @@
          }
      }
  
-@@ -230,6 +239,11 @@
+@@ -230,6 +242,11 @@
       */
      private static void creatureSpecificInit(EntityLiving par0EntityLiving, World par1World, float par2, float par3, float par4)
      {
-+        if (MinecraftForge.EVENT_BUS.post(new LivingSpecialSpawnEvent(par0EntityLiving, par1World, par2, par3, par4)))
++        if (ForgeEventFactory.doSpecialSpawn(par0EntityLiving, par1World, par2, par3, par4))
 +        {
 +            return;
 +        }