5 files changed, 63 insertions, 44 deletions

diff --git a/src/Blocks/BlockFarmland.h b/src/Blocks/BlockFarmland.h
index 23a7392da..8d43632ff 100644
--- a/src/Blocks/BlockFarmland.h
+++ b/src/Blocks/BlockFarmland.h
@@ -65,13 +65,22 @@ public:
 		}
 	}
 
-	virtual void OnNeighborChanged(cChunkInterface & a_ChunkInterface, int a_BlockX, int a_BlockY, int a_BlockZ) override
+
+	virtual void OnNeighborChanged(cChunkInterface & a_ChunkInterface, int a_BlockX, int a_BlockY, int a_BlockZ, eBlockFace a_WhichNeighbor) override
 	{
+		// Don't care about any neighbor but the one above us (fix recursion loop in #2213):
+		if (a_WhichNeighbor != BLOCK_FACE_YP)
+		{
+			return;
+		}
+
+		// Don't care about anything if we're at the top of the world:
 		if (a_BlockY >= cChunkDef::Height)
 		{
 			return;
 		}
 
+		// Check whether we should revert to dirt:
 		BLOCKTYPE UpperBlock = a_ChunkInterface.GetBlock(a_BlockX, a_BlockY + 1, a_BlockZ);
 		if (cBlockInfo::FullyOccupiesVoxel(UpperBlock))
 		{
@@ -79,11 +88,13 @@ public:
 		}
 	}
 
+
 	virtual void ConvertToPickups(cItems & a_Pickups, NIBBLETYPE a_BlockMeta) override
 	{
 		a_Pickups.Add(E_BLOCK_DIRT, 1, 0);  // Reset meta
 	}
 
+
 	bool IsWaterInNear(cChunk & a_Chunk, int a_RelX, int a_RelY, int a_RelZ)
 	{
 		if (a_Chunk.GetWorld()->IsWeatherWetAt(a_RelX, a_RelZ))
diff --git a/src/Blocks/BlockHandler.cpp b/src/Blocks/BlockHandler.cpp
index 520d0d328..412fc3aeb 100644
--- a/src/Blocks/BlockHandler.cpp
+++ b/src/Blocks/BlockHandler.cpp
@@ -389,12 +389,12 @@ void cBlockHandler::OnDestroyedByPlayer(cChunkInterface & a_ChunkInterface, cWor
 void cBlockHandler::OnPlaced(cChunkInterface & a_ChunkInterface, cWorldInterface & a_WorldInterface, int a_BlockX, int a_BlockY, int a_BlockZ, BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta)
 {
 	// Notify the neighbors
-	NeighborChanged(a_ChunkInterface, a_BlockX - 1, a_BlockY, a_BlockZ);
-	NeighborChanged(a_ChunkInterface, a_BlockX + 1, a_BlockY, a_BlockZ);
-	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY - 1, a_BlockZ);
-	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY + 1, a_BlockZ);
-	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY, a_BlockZ - 1);
-	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY, a_BlockZ + 1);
+	NeighborChanged(a_ChunkInterface, a_BlockX - 1, a_BlockY, a_BlockZ, BLOCK_FACE_XP);
+	NeighborChanged(a_ChunkInterface, a_BlockX + 1, a_BlockY, a_BlockZ, BLOCK_FACE_XM);
+	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY - 1, a_BlockZ, BLOCK_FACE_YP);
+	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY + 1, a_BlockZ, BLOCK_FACE_YM);
+	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY, a_BlockZ - 1, BLOCK_FACE_ZP);
+	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY, a_BlockZ + 1, BLOCK_FACE_ZM);
 }
 
 
@@ -404,23 +404,23 @@ void cBlockHandler::OnPlaced(cChunkInterface & a_ChunkInterface, cWorldInterface
 void cBlockHandler::OnDestroyed(cChunkInterface & a_ChunkInterface, cWorldInterface & a_WorldInterface, int a_BlockX, int a_BlockY, int a_BlockZ)
 {
 	// Notify the neighbors
-	NeighborChanged(a_ChunkInterface, a_BlockX - 1, a_BlockY, a_BlockZ);
-	NeighborChanged(a_ChunkInterface, a_BlockX + 1, a_BlockY, a_BlockZ);
-	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY - 1, a_BlockZ);
-	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY + 1, a_BlockZ);
-	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY, a_BlockZ - 1);
-	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY, a_BlockZ + 1);
+	NeighborChanged(a_ChunkInterface, a_BlockX - 1, a_BlockY, a_BlockZ, BLOCK_FACE_XP);
+	NeighborChanged(a_ChunkInterface, a_BlockX + 1, a_BlockY, a_BlockZ, BLOCK_FACE_XM);
+	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY - 1, a_BlockZ, BLOCK_FACE_YP);
+	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY + 1, a_BlockZ, BLOCK_FACE_YM);
+	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY, a_BlockZ - 1, BLOCK_FACE_ZP);
+	NeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY, a_BlockZ + 1, BLOCK_FACE_ZM);
 }
 
 
 
 
 
-void cBlockHandler::NeighborChanged(cChunkInterface & a_ChunkInterface, int a_BlockX, int a_BlockY, int a_BlockZ)
+void cBlockHandler::NeighborChanged(cChunkInterface & a_ChunkInterface, int a_NeighborX, int a_NeighborY, int a_NeighborZ, eBlockFace a_WhichNeighbor)
 {
-	if ((a_BlockY >= 0) && (a_BlockY < cChunkDef::Height))
+	if ((a_NeighborY >= 0) && (a_NeighborY < cChunkDef::Height))
 	{
-		cBlockInfo::GetHandler(a_ChunkInterface.GetBlock(a_BlockX, a_BlockY, a_BlockZ))->OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY, a_BlockZ);
+		cBlockInfo::GetHandler(a_ChunkInterface.GetBlock(a_NeighborX, a_NeighborY, a_NeighborZ))->OnNeighborChanged(a_ChunkInterface, a_NeighborX, a_NeighborY, a_NeighborZ, a_WhichNeighbor);
 	}
 }
 
diff --git a/src/Blocks/BlockHandler.h b/src/Blocks/BlockHandler.h
index a71c70e8b..1b357c3f1 100644
--- a/src/Blocks/BlockHandler.h
+++ b/src/Blocks/BlockHandler.h
@@ -56,13 +56,19 @@ public:
 	/// Called before a block gets destroyed / replaced with air
 	virtual void OnDestroyed(cChunkInterface & a_ChunkInterface, cWorldInterface & a_WorldInterface, int a_BlockX, int a_BlockY, int a_BlockZ);
 	
-	/// Called when a direct neighbor of this block has been changed (The position is the own position, not the neighbor position)
-	virtual void OnNeighborChanged(cChunkInterface & a_ChunkInterface, int a_BlockX, int a_BlockY, int a_BlockZ) {}
-	
-	/// Notifies all neighbors of the given block about a change
-	static void NeighborChanged(cChunkInterface & a_ChunkInterface, int a_BlockX, int a_BlockY, int a_BlockZ);
-	
-	/// Called while the player diggs the block.
+	/** Called when a direct neighbor of this block has been changed (The position is the block's own position, not the changing neighbor's position)
+	a_WhichNeighbor indicates which neighbor has changed. For example, BLOCK_FACE_YP meant the neighbor above has changed.
+	BLOCK_FACE_NONE means that it is a neighbor not directly adjacent (diagonal, etc.) */
+	virtual void OnNeighborChanged(cChunkInterface & a_ChunkInterface, int a_BlockX, int a_BlockY, int a_BlockZ, eBlockFace a_WhichNeighbor) {}
+	
+	/** Notifies the specified neighbor that the current block has changed.
+	a_NeighborXYZ coords are the coords of the neighbor
+	a_WhichNeighbor specifies which neighbor (relative to a_NeighborXYZ) has changed.
+	For example BLOCK_FACE_YP means that the block at {a_NeighborX, a_NeighborY + 1, a_NeighborZ} has changed.
+	BLOCK_FACE_NONE means that it is a neighbor not directly adjacent (diagonal, etc.) */
+	static void NeighborChanged(cChunkInterface & a_ChunkInterface, int a_NeighborX, int a_NeighborY, int a_NeighborZ, eBlockFace a_WhichNeighbor);
+	
+	/** Called when the player starts digging the block. */
 	virtual void OnDigging(cChunkInterface & cChunkInterface, cWorldInterface & a_WorldInterface, cPlayer * a_Player, int a_BlockX, int a_BlockY, int a_BlockZ) {}
 	
 	/// Called if the user right clicks the block and the block is useable
diff --git a/src/Blocks/BlockLeaves.h b/src/Blocks/BlockLeaves.h
index 5c9283979..2368eab7b 100644
--- a/src/Blocks/BlockLeaves.h
+++ b/src/Blocks/BlockLeaves.h
@@ -75,10 +75,14 @@ public:
 	}
 
 
-	virtual void OnNeighborChanged(cChunkInterface & a_ChunkInterface, int a_BlockX, int a_BlockY, int a_BlockZ) override
+	virtual void OnNeighborChanged(cChunkInterface & a_ChunkInterface, int a_BlockX, int a_BlockY, int a_BlockZ, eBlockFace a_WhichNeighbor) override
 	{
+		// Unset 0x8 bit so this block gets checked for decay:
 		NIBBLETYPE Meta = a_ChunkInterface.GetBlockMeta(a_BlockX, a_BlockY, a_BlockZ);
-		a_ChunkInterface.SetBlockMeta(a_BlockX, a_BlockY, a_BlockZ, Meta & 0x7);  // Unset 0x8 bit so it gets checked for decay
+		if ((Meta & 0x08) != 0)
+		{
+			a_ChunkInterface.SetBlockMeta(a_BlockX, a_BlockY, a_BlockZ, Meta & 0x7);
+		}
 	}
 	
 	
diff --git a/src/Blocks/BlockRail.h b/src/Blocks/BlockRail.h
index eecd07006..7fb910e8c 100644
--- a/src/Blocks/BlockRail.h
+++ b/src/Blocks/BlockRail.h
@@ -47,15 +47,14 @@ public:
 		super::OnPlaced(a_ChunkInterface, a_WorldInterface, a_BlockX, a_BlockY, a_BlockZ, a_BlockType, a_BlockMeta);
 
 		// Alert diagonal rails
-		OnNeighborChanged(a_ChunkInterface, a_BlockX + 1, a_BlockY + 1, a_BlockZ);
-		OnNeighborChanged(a_ChunkInterface, a_BlockX - 1, a_BlockY + 1, a_BlockZ);
-		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY + 1, a_BlockZ + 1);
-		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY + 1, a_BlockZ - 1);
-
-		OnNeighborChanged(a_ChunkInterface, a_BlockX + 1, a_BlockY - 1, a_BlockZ);
-		OnNeighborChanged(a_ChunkInterface, a_BlockX - 1, a_BlockY - 1, a_BlockZ);
-		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY - 1, a_BlockZ + 1);
-		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY - 1, a_BlockZ - 1);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX + 1, a_BlockY + 1, a_BlockZ, BLOCK_FACE_NONE);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX - 1, a_BlockY + 1, a_BlockZ, BLOCK_FACE_NONE);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY + 1, a_BlockZ + 1, BLOCK_FACE_NONE);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY + 1, a_BlockZ - 1, BLOCK_FACE_NONE);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX + 1, a_BlockY - 1, a_BlockZ, BLOCK_FACE_NONE);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX - 1, a_BlockY - 1, a_BlockZ, BLOCK_FACE_NONE);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY - 1, a_BlockZ + 1, BLOCK_FACE_NONE);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY - 1, a_BlockZ - 1, BLOCK_FACE_NONE);
 	}
 
 
@@ -64,19 +63,18 @@ public:
 		super::OnDestroyed(a_ChunkInterface, a_WorldInterface, a_BlockX, a_BlockY, a_BlockZ);
 
 		// Alert diagonal rails
-		OnNeighborChanged(a_ChunkInterface, a_BlockX + 1, a_BlockY + 1, a_BlockZ);
-		OnNeighborChanged(a_ChunkInterface, a_BlockX - 1, a_BlockY + 1, a_BlockZ);
-		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY + 1, a_BlockZ + 1);
-		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY + 1, a_BlockZ - 1);
-
-		OnNeighborChanged(a_ChunkInterface, a_BlockX + 1, a_BlockY - 1, a_BlockZ);
-		OnNeighborChanged(a_ChunkInterface, a_BlockX - 1, a_BlockY - 1, a_BlockZ);
-		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY - 1, a_BlockZ + 1);
-		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY - 1, a_BlockZ - 1);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX + 1, a_BlockY + 1, a_BlockZ, BLOCK_FACE_NONE);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX - 1, a_BlockY + 1, a_BlockZ, BLOCK_FACE_NONE);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY + 1, a_BlockZ + 1, BLOCK_FACE_NONE);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY + 1, a_BlockZ - 1, BLOCK_FACE_NONE);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX + 1, a_BlockY - 1, a_BlockZ, BLOCK_FACE_NONE);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX - 1, a_BlockY - 1, a_BlockZ, BLOCK_FACE_NONE);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY - 1, a_BlockZ + 1, BLOCK_FACE_NONE);
+		OnNeighborChanged(a_ChunkInterface, a_BlockX, a_BlockY - 1, a_BlockZ - 1, BLOCK_FACE_NONE);
 	}
 
 
-	virtual void OnNeighborChanged(cChunkInterface & a_ChunkInterface, int a_BlockX, int a_BlockY, int a_BlockZ) override
+	virtual void OnNeighborChanged(cChunkInterface & a_ChunkInterface, int a_BlockX, int a_BlockY, int a_BlockZ, eBlockFace a_WhichNeighbor) override
 	{
 		NIBBLETYPE Meta = a_ChunkInterface.GetBlockMeta(a_BlockX, a_BlockY, a_BlockZ);
 		if (IsUnstable(a_ChunkInterface, a_BlockX, a_BlockY, a_BlockZ) && (Meta != FindMeta(a_ChunkInterface, a_BlockX, a_BlockY, a_BlockZ)))