2 files changed, 48 insertions, 32 deletions

diff --git a/source/Simulator/SandSimulator.cpp b/source/Simulator/SandSimulator.cpp
index 84646a10a..baab76d67 100644
--- a/source/Simulator/SandSimulator.cpp
+++ b/source/Simulator/SandSimulator.cpp
@@ -101,7 +101,7 @@ void cSandSimulator::AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk *
 	cSandSimulatorChunkData & ChunkData = a_Chunk->GetSandSimulatorData();
 	for (cSandSimulatorChunkData::iterator itr = ChunkData.begin(); itr != ChunkData.end(); ++itr)
 	{
-		if ((itr->x == RelX) && (itr->y == a_BlockY) && (itr->z == a_BlockZ))
+		if ((itr->x == RelX) && (itr->y == a_BlockY) && (itr->z == RelZ))
 		{
 			return;
 		}
@@ -121,10 +121,10 @@ bool cSandSimulator::CanStartFallingThrough(BLOCKTYPE a_BlockType)
 	{
 		case E_BLOCK_AIR:
 		case E_BLOCK_FIRE:
-		case E_BLOCK_WATER:
-		case E_BLOCK_STATIONARY_WATER:
 		case E_BLOCK_LAVA:
 		case E_BLOCK_STATIONARY_LAVA:
+		case E_BLOCK_STATIONARY_WATER:
+		case E_BLOCK_WATER:
 		{
 			return true;
 		}
@@ -141,33 +141,41 @@ bool cSandSimulator::CanContinueFallThrough(BLOCKTYPE a_BlockType)
 	switch (a_BlockType)
 	{
 		case E_BLOCK_AIR:
+		case E_BLOCK_BROWN_MUSHROOM:
+		case E_BLOCK_COBWEB:
+		case E_BLOCK_CROPS:
+		case E_BLOCK_DEAD_BUSH:
+		case E_BLOCK_DETECTOR_RAIL:
 		case E_BLOCK_FIRE:
-		case E_BLOCK_WATER:
-		case E_BLOCK_STATIONARY_WATER:
+		case E_BLOCK_FLOWER_POT:
 		case E_BLOCK_LAVA:
-		case E_BLOCK_STATIONARY_LAVA:
+		case E_BLOCK_LEVER:
+		case E_BLOCK_MINECART_TRACKS:
+		case E_BLOCK_MELON_STEM:
 		case E_BLOCK_POWERED_RAIL:
-		case E_BLOCK_DETECTOR_RAIL:
-		case E_BLOCK_COBWEB:
-		case E_BLOCK_TALL_GRASS:
-		case E_BLOCK_DEAD_BUSH:
-		case E_BLOCK_YELLOW_FLOWER:
-		case E_BLOCK_RED_ROSE:
-		case E_BLOCK_BROWN_MUSHROOM:
-		case E_BLOCK_RED_MUSHROOM:
-		case E_BLOCK_TORCH:
-		case E_BLOCK_REDSTONE_WIRE:
-		case E_BLOCK_CROPS:
 		case E_BLOCK_PUMPKIN_STEM:
-		case E_BLOCK_MELON_STEM:
+		case E_BLOCK_REDSTONE_REPEATER_OFF:
+		case E_BLOCK_REDSTONE_REPEATER_ON:
 		case E_BLOCK_REDSTONE_TORCH_OFF:
 		case E_BLOCK_REDSTONE_TORCH_ON:
+		case E_BLOCK_REDSTONE_WIRE:
+		case E_BLOCK_RED_MUSHROOM:
+		case E_BLOCK_RED_ROSE:
+		case E_BLOCK_SIGN_POST:
+		case E_BLOCK_STATIONARY_LAVA:
+		case E_BLOCK_STATIONARY_WATER:
 		case E_BLOCK_STONE_BUTTON:
 		case E_BLOCK_STONE_PRESSURE_PLATE:
+		case E_BLOCK_TALL_GRASS:
+		case E_BLOCK_TORCH:
+		case E_BLOCK_TRAPDOOR:
+		case E_BLOCK_TRIPWIRE:
+		case E_BLOCK_TRIPWIRE_HOOK:
+		case E_BLOCK_WALLSIGN:
+		case E_BLOCK_WATER:
 		case E_BLOCK_WOODEN_BUTTON:
 		case E_BLOCK_WOODEN_PRESSURE_PLATE:
-		case E_BLOCK_REDSTONE_REPEATER_OFF:
-		case E_BLOCK_REDSTONE_REPEATER_ON:
+		case E_BLOCK_YELLOW_FLOWER:
 		{
 			return true;
 		}
@@ -184,13 +192,13 @@ bool cSandSimulator::IsReplacedOnRematerialization(BLOCKTYPE a_BlockType)
 	switch (a_BlockType)
 	{
 		case E_BLOCK_AIR:
+		case E_BLOCK_DEAD_BUSH:
 		case E_BLOCK_FIRE:
-		case E_BLOCK_WATER:
-		case E_BLOCK_STATIONARY_WATER:
 		case E_BLOCK_LAVA:
 		case E_BLOCK_STATIONARY_LAVA:
+		case E_BLOCK_STATIONARY_WATER:
 		case E_BLOCK_TALL_GRASS:
-		case E_BLOCK_DEAD_BUSH:
+		case E_BLOCK_WATER:
 		{
 			return true;
 		}
@@ -202,14 +210,14 @@ bool cSandSimulator::IsReplacedOnRematerialization(BLOCKTYPE a_BlockType)
 
 
 
-bool cSandSimulator::DoesBreakFallingThrough(BLOCKTYPE a_BlockType)
+bool cSandSimulator::DoesBreakFallingThrough(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta)
 {
 	switch (a_BlockType)
 	{
 		case E_BLOCK_STONE_SLAB:
 		case E_BLOCK_WOODEN_SLAB:
 		{
-			return true;
+			return ((a_BlockMeta & 0x08) == 0);  // Only a bottom-slab breaks the block
 		}
 	}
 	return false;
@@ -255,11 +263,19 @@ void cSandSimulator::DoInstantFall(cChunk * a_Chunk, int a_RelX, int a_RelY, int
 	// Search for a place to put it:
 	for (int y = a_RelY - 1; y >= 0; y--)
 	{
-		BLOCKTYPE BlockType = a_Chunk->GetBlock(a_RelX, y, a_RelZ);
-		if (
-			!DoesBreakFallingThrough(BlockType) &&
-			CanContinueFallThrough(BlockType)
-		)
+		BLOCKTYPE BlockType;
+		NIBBLETYPE BlockMeta;
+		a_Chunk->GetBlockTypeMeta(a_RelX, y, a_RelZ, BlockType, BlockMeta);
+		int BlockY;
+		if (DoesBreakFallingThrough(BlockType, BlockMeta))
+		{
+			BlockY = y;
+		}
+		else if (!CanContinueFallThrough(BlockType))
+		{
+			BlockY = y + 1;
+		}
+		else
 		{
 			// Can fall further down
 			continue;
@@ -268,7 +284,7 @@ void cSandSimulator::DoInstantFall(cChunk * a_Chunk, int a_RelX, int a_RelY, int
 		// Finish the fall at the found bottom:
 		int BlockX = a_RelX + a_Chunk->GetPosX() * cChunkDef::Width;
 		int BlockZ = a_RelZ + a_Chunk->GetPosZ() * cChunkDef::Width;
-		FinishFalling(&m_World, BlockX, y + 1, BlockZ, FallingBlockType, FallingBlockMeta);
+		FinishFalling(&m_World, BlockX, BlockY, BlockZ, FallingBlockType, FallingBlockMeta);
 		return;
 	}
 	
diff --git a/source/Simulator/SandSimulator.h b/source/Simulator/SandSimulator.h
index 571258049..6e9ea15ac 100644
--- a/source/Simulator/SandSimulator.h
+++ b/source/Simulator/SandSimulator.h
@@ -29,7 +29,7 @@ public:
 	static bool IsReplacedOnRematerialization(BLOCKTYPE a_BlockType);
 	
 	/// Returns true if the specified block breaks falling blocks while they fall through it (e. g. halfslabs)
-	static bool DoesBreakFallingThrough(BLOCKTYPE a_BlockType);
+	static bool DoesBreakFallingThrough(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta);
 	
 	/** Called when a block finishes falling at the specified coords, either by insta-fall,
 	or through cFallingBlock entity.