6 files changed, 34 insertions, 48 deletions

diff --git a/src/Blocks/BlockFluid.h b/src/Blocks/BlockFluid.h
index 37885e4de..d486d642d 100644
--- a/src/Blocks/BlockFluid.h
+++ b/src/Blocks/BlockFluid.h
@@ -93,6 +93,7 @@ public:
 		// Check if it's fuel:
 		BLOCKTYPE BlockType;
 		if (
+			((a_RelY + y < 0) || (a_RelY + y > cChunkDef::Height)) ||
 			!a_Chunk.UnboundedRelGetBlockType(a_RelX + x, a_RelY + y, a_RelZ + z, BlockType) ||
 			!cFireSimulator::IsFuel(BlockType)
 		)
@@ -119,6 +120,7 @@ public:
 		for (size_t i = 0; i < ARRAYCOUNT(CrossCoords); i++)
 		{
 			if (
+				((RelY + CrossCoords[i].y >= 0) && (RelY + CrossCoords[i].y <= cChunkDef::Height)) &&
 				a_Chunk.UnboundedRelGetBlockType(RelX + CrossCoords[i].x, RelY + CrossCoords[i].y, RelZ + CrossCoords[i].z, BlockType) &&
 				(BlockType == E_BLOCK_AIR)
 			)
diff --git a/src/Blocks/BlockSlab.h b/src/Blocks/BlockSlab.h
index 4f94d45f6..76f5ed0e7 100644
--- a/src/Blocks/BlockSlab.h
+++ b/src/Blocks/BlockSlab.h
@@ -11,6 +11,7 @@
 
 #include "BlockHandler.h"
 #include "../Items/ItemHandler.h"
+#include "Root.h"
 
 
 
@@ -38,41 +39,9 @@ public:
 	) override
 	{
 		a_BlockType = m_BlockType;
-		BLOCKTYPE  Type = (BLOCKTYPE) (a_Player->GetEquippedItem().m_ItemType);
 		NIBBLETYPE Meta = (NIBBLETYPE) a_Player->GetEquippedItem().m_ItemDamage;
 		
-		// HandlePlaceBlock wants a cItemHandler pointer thing, so let's give it one
-		cItemHandler * ItemHandler = cItemHandler::GetItemHandler(GetDoubleSlabType(Type));
-
-		// Check if the block at the coordinates is a slab. Eligibility for combining has already been processed in ClientHandle
-		if (IsAnySlabType(a_ChunkInterface.GetBlock(a_BlockX, a_BlockY, a_BlockZ)))
-		{
-			// Call the function in ClientHandle that places a block when the client sends the packet,
-			// so that plugins may interfere with the placement.
-			
-			if ((a_BlockFace == BLOCK_FACE_TOP) || (a_BlockFace == BLOCK_FACE_BOTTOM))
-			{
-				// Top and bottom faces need no parameter modification
-				a_Player->GetClientHandle()->HandlePlaceBlock(a_BlockX, a_BlockY, a_BlockZ, a_BlockFace, a_CursorX, a_CursorY, a_CursorZ, *ItemHandler);
-			}
-			else
-			{
-				// The other faces need to distinguish between top and bottom cursor positions
-				if (a_CursorY > 7)
-				{
-					// Edit the call to use BLOCK_FACE_BOTTOM, otherwise it places incorrectly
-					a_Player->GetClientHandle()->HandlePlaceBlock(a_BlockX, a_BlockY, a_BlockZ, BLOCK_FACE_TOP, a_CursorX, a_CursorY, a_CursorZ, *ItemHandler);
-				}
-				else
-				{
-					// Edit the call to use BLOCK_FACE_TOP, otherwise it places incorrectly
-					a_Player->GetClientHandle()->HandlePlaceBlock(a_BlockX, a_BlockY, a_BlockZ, BLOCK_FACE_BOTTOM, a_CursorX, a_CursorY, a_CursorZ, *ItemHandler);
-				}
-			}
-			return false;  // Cancel the event, because dblslabs were already placed, nothing else needed
-		}
-		
-		// Place the single-slab with correct metas:
+		// Set the correct metadata based on player equipped item (i.e. a_BlockMeta not initialised yet)
 		switch (a_BlockFace)
 		{
 			case BLOCK_FACE_TOP:
@@ -105,6 +74,14 @@ public:
 			}
 			case BLOCK_FACE_NONE: return false;
 		}  // switch (a_BlockFace)
+
+		// Check if the block at the coordinates is a single slab. Eligibility for combining has already been processed in ClientHandle
+		// Changed to-be-placed to a double slab if we are clicking on a single slab, as opposed to placing one for the first time
+		if (IsAnySlabType(a_ChunkInterface.GetBlock(a_BlockX, a_BlockY, a_BlockZ)))
+		{
+			a_BlockType = GetDoubleSlabType(m_BlockType);
+		}
+
 		return true;
 	}
 	
diff --git a/src/ClientHandle.cpp b/src/ClientHandle.cpp
index 5ed5f1085..23ba4dbab 100644
--- a/src/ClientHandle.cpp
+++ b/src/ClientHandle.cpp
@@ -1064,7 +1064,7 @@ void cClientHandle::HandlePlaceBlock(int a_BlockX, int a_BlockY, int a_BlockZ, e
 		// If clicked top face and slab occupies the top voxel, we want a slab to be placed above it (therefore increment Y)
 		// Else if clicked bottom face and slab occupies the bottom voxel, decrement Y for the same reason
 		// Don't touch coordinates if anything else because a dblslab opportunity is present
-		if((ClickedBlockMeta & 0x08) && (a_BlockFace == BLOCK_FACE_TOP))
+		if ((ClickedBlockMeta & 0x08) && (a_BlockFace == BLOCK_FACE_TOP))
 		{
 			++a_BlockY;
 		}
diff --git a/src/ClientHandle.h b/src/ClientHandle.h
index 8366caa16..5496e61a7 100644
--- a/src/ClientHandle.h
+++ b/src/ClientHandle.h
@@ -230,10 +230,10 @@ public:
 	/** Called when the player moves into a different world; queues sreaming the new chunks */
 	void MoveToWorld(cWorld & a_World, bool a_SendRespawnPacket);
 	
+private:
+
 	/** Handles the block placing packet when it is a real block placement (not block-using, item-using or eating) */
 	void HandlePlaceBlock(int a_BlockX, int a_BlockY, int a_BlockZ, eBlockFace a_BlockFace, int a_CursorX, int a_CursorY, int a_CursorZ, cItemHandler & a_ItemHandler);
-	
-private:
 
 	/** The type used for storing the names of registered plugin channels. */
 	typedef std::set<AString> cChannels;
diff --git a/src/MobSpawner.cpp b/src/MobSpawner.cpp
index a0d0f5c54..05da5d01c 100644
--- a/src/MobSpawner.cpp
+++ b/src/MobSpawner.cpp
@@ -129,6 +129,11 @@ bool cMobSpawner::CanSpawnHere(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_R
 	BLOCKTYPE TargetBlock = E_BLOCK_AIR;
 	if (m_AllowedTypes.find(a_MobType) != m_AllowedTypes.end() && a_Chunk->UnboundedRelGetBlockType(a_RelX, a_RelY, a_RelZ, TargetBlock))
 	{
+		if ((a_RelY + 1 > cChunkDef::Height) || (a_RelY - 1 < 0))
+		{
+			return false;
+		}
+
 		NIBBLETYPE BlockLight = a_Chunk->GetBlockLight(a_RelX, a_RelY, a_RelZ);
 		NIBBLETYPE SkyLight = a_Chunk->GetSkyLight(a_RelX, a_RelY, a_RelZ);
 		BLOCKTYPE BlockAbove = a_Chunk->GetBlock(a_RelX, a_RelY + 1, a_RelZ);
@@ -200,7 +205,7 @@ bool cMobSpawner::CanSpawnHere(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_R
 			case cMonster::mtSpider:
 			{
 				bool CanSpawn = true;
-				bool HaveFloor = false;
+				bool HasFloor = false;
 				for (int x = 0; x < 2; ++x)
 				{
 					for(int z = 0; z < 2; ++z)
@@ -211,8 +216,8 @@ bool cMobSpawner::CanSpawnHere(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_R
 						{
 							return false;
 						}
-						HaveFloor = (
-							HaveFloor ||
+						HasFloor = (
+							HasFloor ||
 							(
 								a_Chunk->UnboundedRelGetBlockType(a_RelX + x, a_RelY - 1, a_RelZ + z, TargetBlock) &&
 								!cBlockInfo::IsTransparent(TargetBlock)
@@ -220,7 +225,7 @@ bool cMobSpawner::CanSpawnHere(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_R
 						);
 					}
 				}
-				return CanSpawn && HaveFloor && (SkyLight <= 7) && (BlockLight <= 7);
+				return CanSpawn && HasFloor && (SkyLight <= 7) && (BlockLight <= 7);
 			}
 			
 			case cMonster::mtCreeper:
diff --git a/src/Mobs/Monster.cpp b/src/Mobs/Monster.cpp
index d3e0f1c26..aa6071515 100644
--- a/src/Mobs/Monster.cpp
+++ b/src/Mobs/Monster.cpp
@@ -111,9 +111,9 @@ void cMonster::SpawnOn(cClientHandle & a_Client)
 
 void cMonster::TickPathFinding()
 {
-	int PosX = (int)floor(GetPosX());
-	int PosY = (int)floor(GetPosY());
-	int PosZ = (int)floor(GetPosZ());
+	const int PosX = (int)floor(GetPosX());
+	const int PosY = (int)floor(GetPosY());
+	const int PosZ = (int)floor(GetPosZ());
 
 	m_FinalDestination.y = (double)FindFirstNonAirBlockPosition(m_FinalDestination.x, m_FinalDestination.z);
 
@@ -130,14 +130,16 @@ void cMonster::TickPathFinding()
 		{ 0, 1},
 		{ 0,-1},
 	} ;
+	
+	if ((PosY - 1 < 0) || (PosY + 2 > cChunkDef::Height) /* PosY + 1 will never be true if PosY + 2 is not */)
+	{
+		// Too low/high, can't really do anything
+		FinishPathFinding();
+		return;
+	}
 
 	for (size_t i = 0; i < ARRAYCOUNT(gCrossCoords); i++)
 	{
-		if ((gCrossCoords[i].x + PosX == PosX) && (gCrossCoords[i].z + PosZ == PosZ))
-		{
-			continue;
-		}
-
 		if (IsCoordinateInTraversedList(Vector3i(gCrossCoords[i].x + PosX, PosY, gCrossCoords[i].z + PosZ)))
 		{
 			continue;