Added CreateSpawnPosition event.

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

@@ -174,7 +174,15 @@
          return !this.field_73061_a.func_175579_a(this, p_175660_2_, p_175660_1_) && this.func_175723_af().func_177746_a(p_175660_2_);
      }
  
-@@ -855,7 +898,7 @@
+@@ -810,6 +853,7 @@
+         }
+         else
+         {
++            if (net.minecraftforge.event.ForgeEventFactory.onCreateWorldSpawn(this, p_73052_1_)) return;
+             this.field_72987_B = true;
+             WorldChunkManager worldchunkmanager = this.field_73011_w.func_177499_m();
+             List list = worldchunkmanager.func_76932_a();
+@@ -855,7 +899,7 @@
  
      protected void func_73047_i()
      {
@@ -183,7 +191,7 @@
  
          for (int i = 0; i < 10; ++i)
          {
-@@ -892,6 +935,7 @@
+@@ -892,6 +936,7 @@
              }
  
              this.field_73020_y.func_73151_a(p_73044_1_, p_73044_2_);
@@ -191,7 +199,7 @@
              List list = this.field_73059_b.func_152380_a();
              Iterator iterator = list.iterator();
  
-@@ -929,6 +973,7 @@
+@@ -929,6 +974,7 @@
          this.field_72986_A.func_176135_e(this.func_175723_af().func_177732_i());
          this.field_73019_z.func_75755_a(this.field_72986_A, this.field_73061_a.func_71203_ab().func_72378_q());
          this.field_72988_C.func_75744_a();
@@ -199,7 +207,7 @@
      }
  
      public void func_72923_a(Entity p_72923_1_)
-@@ -984,6 +1029,7 @@
+@@ -984,6 +1030,7 @@
      public Explosion func_72885_a(Entity p_72885_1_, double p_72885_2_, double p_72885_4_, double p_72885_6_, float p_72885_8_, boolean p_72885_9_, boolean p_72885_10_)
      {
          Explosion explosion = new Explosion(this, p_72885_1_, p_72885_2_, p_72885_4_, p_72885_6_, p_72885_8_, p_72885_9_, p_72885_10_);
@@ -207,7 +215,7 @@
          explosion.func_77278_a();
          explosion.func_77279_a(false);
  
-@@ -1074,19 +1120,23 @@
+@@ -1074,19 +1121,23 @@
              this.field_73061_a.func_71203_ab().func_148537_a(new S2BPacketChangeGameState(8, this.field_73017_q), this.field_73011_w.func_177502_q());
          }
  
@@ -235,7 +243,7 @@
          }
      }
  
-@@ -1152,6 +1202,11 @@
+@@ -1152,6 +1203,11 @@
          return this.field_73061_a.func_152345_ab();
      }
  

src/main/java/net/minecraftforge/event/ForgeEventFactory.java

@@ -27,6 +27,7 @@ import net.minecraft.util.Vec3;
 import net.minecraft.world.Explosion;
 import net.minecraft.world.World;
 import net.minecraft.world.WorldServer;
+import net.minecraft.world.WorldSettings;
 import net.minecraft.world.biome.BiomeGenBase;
 import net.minecraft.world.storage.IPlayerFileData;
 import net.minecraft.world.storage.SaveHandler;
@@ -372,4 +373,9 @@ public class ForgeEventFactory
         */
         MinecraftForge.EVENT_BUS.post(new ExplosionEvent.Detonate(world, explosion, list));
     }
+
+    public static boolean onCreateWorldSpawn(World world, WorldSettings settings)
+    {
+        return MinecraftForge.EVENT_BUS.post(new WorldEvent.CreateSpawnPosition(world, settings));
+    }
 }

src/main/java/net/minecraftforge/event/world/WorldEvent.java

@@ -2,9 +2,11 @@ package net.minecraftforge.event.world;
 
 import java.util.ArrayList;
 import java.util.List;
+
 import net.minecraft.entity.EnumCreatureType;
 import net.minecraft.util.BlockPos;
 import net.minecraft.world.World;
+import net.minecraft.world.WorldSettings;
 import net.minecraft.world.biome.BiomeGenBase.SpawnListEntry;
 import net.minecraftforge.fml.common.eventhandler.Cancelable;
 import net.minecraftforge.fml.common.eventhandler.Event;
@@ -109,4 +111,19 @@ public class WorldEvent extends Event
             }
         }
     }
+
+    /**
+     * Called by WorldServer when it attempts to create a spawnpoint for a dimension.
+     * Canceling the event will prevent the vanilla code from running.
+     */
+    @Cancelable
+    public static class CreateSpawnPosition extends WorldEvent
+    {
+        public final WorldSettings settings;
+        public CreateSpawnPosition(World world, WorldSettings settings)
+        {
+            super(world);
+            this.settings = settings;
+        }
+    }
 }