1 files changed, 21 insertions, 9 deletions

diff --git a/source/ClientHandle.cpp b/source/ClientHandle.cpp
index 8ff93ec1b..199f43014 100644
--- a/source/ClientHandle.cpp
+++ b/source/ClientHandle.cpp
@@ -854,19 +854,29 @@ void cClientHandle::HandlePlaceBlock(int a_BlockX, int a_BlockY, int a_BlockZ, c
 
 	World->GetBlockTypeMeta(a_BlockX, a_BlockY, a_BlockZ, ClickedBlock, ClickedBlockMeta);
 
-	//Special slab handler coding
+	// Special slab handler coding
 	if (
+		// If clicked face top: is slab there in the "bottom" position?
+		// If clicked face bottom: is the slab there in the "top" position?
+		// This prevents a dblslab forming below if you click the top face of a "top" slab.
 		(((a_BlockFace == BLOCK_FACE_TOP) && (ClickedBlockMeta == (EquippedBlockDamage & 0x07))) || ((a_BlockFace == BLOCK_FACE_BOTTOM) && (ClickedBlockMeta == (EquippedBlockDamage | 0x08)))) &&
-		((ClickedBlock == E_BLOCK_STONE_SLAB) || (ClickedBlock == E_BLOCK_WOODEN_SLAB)) && //Is clicked a slab?
-		((EquippedBlock == E_BLOCK_STONE_SLAB) || (EquippedBlock == E_BLOCK_WOODEN_SLAB)) && //Is equipped a slab?		
-		((ClickedBlockMeta & 0x07) == (EquippedBlockDamage & 0x07)) //Is clicked same type of slab as item in hand?
+		
+		// Is clicked a slab? This is a SLAB handler, not stone or something!
+		((ClickedBlock == E_BLOCK_STONE_SLAB) || (ClickedBlock == E_BLOCK_WOODEN_SLAB)) &&
+		
+		// Is equipped a some type of slab?
+		// This prevents a bug where, well, you get a dblslab by placing TNT or something not a slab.
+		((EquippedBlock == E_BLOCK_STONE_SLAB) || (EquippedBlock == E_BLOCK_WOODEN_SLAB)) &&
+		
+		// Is equipped slab type same as the slab in the world? After all, we can't combine different slabs!
+		((ClickedBlockMeta & 0x07) == (EquippedBlockDamage & 0x07))
 		)
 	{
-		//Don't move the coordinates
+		// Coordinates at CLICKED block, don't move them anywhere
 	}
 	else
 	{
-		//Check if the block ignores build collision (water, grass etc.):
+		// Check if the block ignores build collision (water, grass etc.):
 		cBlockHandler * Handler = cBlockHandler::GetBlockHandler(ClickedBlock);
 		if (Handler->DoesIgnoreBuildCollision())
 		{
@@ -876,8 +886,9 @@ void cClientHandle::HandlePlaceBlock(int a_BlockX, int a_BlockY, int a_BlockZ, c
 		else
 		{
 			AddFaceDirection(a_BlockX, a_BlockY, a_BlockZ, a_BlockFace);
-			//On side of block, make sure that placement won't be cancelled if there is a slab there
-			//No need to combinability checks, client will do that
+			
+			// Clicked on side of block, make sure that placement won't be cancelled if there is a slab able to be double slabbed.
+			// No need to do combinability (dblslab) checks, client will do that here.
 			if ((World->GetBlock(a_BlockX, a_BlockY, a_BlockZ) == E_BLOCK_STONE_SLAB) || (World->GetBlock(a_BlockX, a_BlockY, a_BlockZ) == E_BLOCK_WOODEN_SLAB))
 			{
 				//Is a slab, don't do checks and proceed to double-slabbing
@@ -904,7 +915,8 @@ void cClientHandle::HandlePlaceBlock(int a_BlockX, int a_BlockY, int a_BlockZ, c
 			}
 		}
 	}
-
+	// Special slab handler coding end
+	
 	BLOCKTYPE BlockType;
 	NIBBLETYPE BlockMeta;
 	if (!a_ItemHandler.GetPlacementBlockTypeMeta(World, m_Player, a_BlockX, a_BlockY, a_BlockZ, a_BlockFace, a_CursorX, a_CursorY, a_CursorZ, BlockType, BlockMeta))