Merge remote-tracking branch 'origin/pr/3110' into 1.10.x

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

@@ -98,6 +98,7 @@ import net.minecraftforge.event.entity.player.UseHoeEvent;
 import net.minecraftforge.event.terraingen.ChunkGeneratorEvent;
 import net.minecraftforge.event.terraingen.PopulateChunkEvent;
 import net.minecraftforge.event.world.BlockEvent;
+import net.minecraftforge.event.world.BlockEvent.CreateFluidSourceEvent;
 import net.minecraftforge.event.world.BlockEvent.MultiPlaceEvent;
 import net.minecraftforge.event.world.BlockEvent.NeighborNotifyEvent;
 import net.minecraftforge.event.world.BlockEvent.PlaceEvent;
@@ -585,4 +586,13 @@ public class ForgeEventFactory
         return event.getTable();
     }
 
+    public static boolean canCreateFluidSource(World world, BlockPos pos, IBlockState state, boolean def)
+    {
+        CreateFluidSourceEvent evt = new CreateFluidSourceEvent(world, pos, state);
+        MinecraftForge.EVENT_BUS.post(evt);
+
+        Result result = evt.getResult();
+        return result == Result.DEFAULT ? def : result == Result.ALLOW;
+    }
+
 }

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

@@ -252,4 +252,20 @@ public class BlockEvent extends Event
             return notifiedSides;
         }
     }
+
+    /**
+     * Fired to check whether a non-source block can turn into a source block.
+     * A result of ALLOW causes a source block to be created even if the liquid
+     * usually doesn't do that (like lava), and a result of DENY prevents creation
+     * even if the liquid usually does do that (like water).
+     */
+    @HasResult
+    public static class CreateFluidSourceEvent extends BlockEvent
+    {
+        public CreateFluidSourceEvent(World world, BlockPos pos, IBlockState state)
+        {
+            super(world, pos, state);
+        }
+    }
+
 }

src/main/java/net/minecraftforge/fluids/BlockFluidClassic.java

@@ -27,6 +27,7 @@ import net.minecraft.init.Blocks;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.IBlockAccess;
 import net.minecraft.world.World;
+import net.minecraftforge.event.ForgeEventFactory;
 
 /**
  * This is a fluid block implementation which emulates vanilla Minecraft fluid behavior.
@@ -102,6 +103,17 @@ public class BlockFluidClassic extends BlockFluidBase
     @Override
     public void updateTick(World world, BlockPos pos, IBlockState state, Random rand)
     {
+        if (!isSourceBlock(world, pos) && ForgeEventFactory.canCreateFluidSource(world, pos, state, false))
+        {
+            int adjacentSourceBlocks =
+                    (isSourceBlock(world, pos.north()) ? 1 : 0) +
+                    (isSourceBlock(world, pos.south()) ? 1 : 0) +
+                    (isSourceBlock(world, pos.east()) ? 1 : 0) +
+                    (isSourceBlock(world, pos.west()) ? 1 : 0);
+            if (adjacentSourceBlocks >= 2 && (world.getBlockState(pos.up(densityDir)).getMaterial().isSolid() || isSourceBlock(world, pos.up(densityDir))))
+                world.setBlockState(pos, state.withProperty(LEVEL, 0));
+        }
+
         int quantaRemaining = quantaPerBlock - state.getValue(LEVEL);
         int expQuanta = -101;