13 files changed, 223 insertions, 151 deletions

diff --git a/src/Blocks/BlockBed.h b/src/Blocks/BlockBed.h
index caec2b56f..6daa94730 100644
--- a/src/Blocks/BlockBed.h
+++ b/src/Blocks/BlockBed.h
@@ -4,6 +4,7 @@
 #include "BlockHandler.h"
 #include "ChunkInterface.h"
 #include "WorldInterface.h"
+#include "MetaRotater.h"
 #include "../Entities/Player.h"
 
 
@@ -11,11 +12,11 @@
 
 
 class cBlockBedHandler :
-	public cBlockHandler
+	public cMetaRotater<cBlockHandler, 0x3, 0x02, 0x03, 0x00, 0x01, true>
 {
 public:
 	cBlockBedHandler(BLOCKTYPE a_BlockType)
-		: cBlockHandler(a_BlockType)
+		: cMetaRotater<cBlockHandler, 0x3, 0x02, 0x03, 0x00, 0x01,true>(a_BlockType)
 	{
 	}
 
diff --git a/src/Blocks/BlockButton.h b/src/Blocks/BlockButton.h
index 2db9b7ec7..740cbe3c4 100644
--- a/src/Blocks/BlockButton.h
+++ b/src/Blocks/BlockButton.h
@@ -2,16 +2,17 @@
 
 #include "BlockHandler.h"
 #include "Chunk.h"
+#include "MetaRotater.h"
 
 
 
 
 class cBlockButtonHandler :
-	public cBlockHandler
+	public cMetaRotater<cBlockHandler, 0x07, 0x04, 0x01, 0x03, 0x02, true>
 {
 public:
 	cBlockButtonHandler(BLOCKTYPE a_BlockType)
-		: cBlockHandler(a_BlockType)
+		: cMetaRotater<cBlockHandler, 0x07, 0x04, 0x01, 0x03, 0x02, true>(a_BlockType)
 	{
 	}
 
diff --git a/src/Blocks/BlockChest.h b/src/Blocks/BlockChest.h
index 02ecc4346..30588d8fc 100644
--- a/src/Blocks/BlockChest.h
+++ b/src/Blocks/BlockChest.h
@@ -4,17 +4,18 @@
 #include "BlockEntity.h"
 #include "../BlockArea.h"
 #include "../Entities/Player.h"
+#include "MetaRotater.h"
 
 
 
 
 
 class cBlockChestHandler :
-	public cBlockEntityHandler
+	public cMetaRotater<cBlockEntityHandler, 0x07, 0x04, 0x01, 0x03, 0x02, true>
 {
 public:
 	cBlockChestHandler(BLOCKTYPE a_BlockType)
-		: cBlockEntityHandler(a_BlockType)
+		: cMetaRotater<cBlockEntityHandler, 0x07, 0x04, 0x01, 0x03, 0x02, true>(a_BlockType)
 	{
 	}
 
diff --git a/src/Blocks/BlockComparator.h b/src/Blocks/BlockComparator.h
index cea35a864..e570ff302 100644
--- a/src/Blocks/BlockComparator.h
+++ b/src/Blocks/BlockComparator.h
@@ -3,17 +3,18 @@
 
 #include "BlockHandler.h"
 #include "BlockRedstoneRepeater.h"
+#include "MetaRotater.h"
 
 
 
 
 
 class cBlockComparatorHandler :
-	public cBlockHandler
+	public cMetaRotater<cBlockHandler, 0x03, 0x00, 0x01, 0x02, 0x03, true>
 {
 public:
 	cBlockComparatorHandler(BLOCKTYPE a_BlockType)
-		: cBlockHandler(a_BlockType)
+		: cMetaRotater<cBlockHandler, 0x03, 0x00, 0x01, 0x02, 0x03, true>(a_BlockType)
 	{
 	}
 
diff --git a/src/Blocks/BlockDoor.cpp b/src/Blocks/BlockDoor.cpp
index 0acf04852..4e38ef334 100644
--- a/src/Blocks/BlockDoor.cpp
+++ b/src/Blocks/BlockDoor.cpp
@@ -9,7 +9,7 @@
 
 
 cBlockDoorHandler::cBlockDoorHandler(BLOCKTYPE a_BlockType)
-	: cBlockHandler(a_BlockType)
+	: super(a_BlockType)
 {
 }
 
diff --git a/src/Blocks/BlockDoor.h b/src/Blocks/BlockDoor.h
index 68be2c658..981774c17 100644
--- a/src/Blocks/BlockDoor.h
+++ b/src/Blocks/BlockDoor.h
@@ -4,13 +4,15 @@
 #include "BlockHandler.h"
 #include "../Entities/Player.h"
 #include "Chunk.h"
+#include "MetaRotater.h"
 
 
 
 
 class cBlockDoorHandler :
-	public cBlockHandler
+	public cMetaRotater<cBlockHandler, 0x03, 0x01, 0x02, 0x03, 0x00, true>
 {
+	typedef cMetaRotater<cBlockHandler, 0x03, 0x01, 0x02, 0x03, 0x00, true> super;
 public:
 	cBlockDoorHandler(BLOCKTYPE a_BlockType);
 
@@ -168,6 +170,60 @@ public:
 	}
 	
 	
+	virtual NIBBLETYPE MetaRotateCCW(NIBBLETYPE a_Meta) override
+	{
+		if (a_Meta & 0x08) 
+		{
+			return a_Meta;
+		}
+		else
+		{
+			return super::MetaRotateCCW(a_Meta);
+		}
+	}
+	
+	
+	
+	virtual NIBBLETYPE MetaRotateCW(NIBBLETYPE a_Meta) override
+	{
+		if (a_Meta & 0x08) 
+		{
+			return a_Meta;
+		}
+		else
+		{
+			return super::MetaRotateCW(a_Meta);
+		}
+	}
+	
+	
+	
+	virtual NIBBLETYPE MetaMirrorXY(NIBBLETYPE a_Meta) override
+	{
+		if (a_Meta & 0x08) 
+		{
+			return a_Meta;
+		}
+		else
+		{
+			return super::MetaMirrorXY(a_Meta);
+		}
+	}
+	
+	
+	
+	virtual NIBBLETYPE MetaMirrorYZ(NIBBLETYPE a_Meta) override
+	{
+		if (a_Meta & 0x08) 
+		{
+			return a_Meta;
+		}
+		else
+		{
+			return super::MetaMirrorYZ(a_Meta);
+		}
+	}
+	
 } ;
 
 
diff --git a/src/Blocks/BlockDropSpenser.h b/src/Blocks/BlockDropSpenser.h
index 30d347ec9..7e0ad0e55 100644
--- a/src/Blocks/BlockDropSpenser.h
+++ b/src/Blocks/BlockDropSpenser.h
@@ -6,17 +6,18 @@
 #pragma once
 
 #include "../Piston.h"
+#include "MetaRotater.h"
 
 
 
 
 
 class cBlockDropSpenserHandler :
-	public cBlockEntityHandler
+	public cMetaRotater<cBlockEntityHandler, 0x07, 0x02, 0x05, 0x03, 0x04>
 {
 public:
 	cBlockDropSpenserHandler(BLOCKTYPE a_BlockType) :
-		cBlockEntityHandler(a_BlockType)
+		cMetaRotater<cBlockEntityHandler, 0x07, 0x02, 0x05, 0x03, 0x04>(a_BlockType)
 	{
 	}
 	
@@ -34,6 +35,20 @@ public:
 		a_BlockMeta = cPiston::RotationPitchToMetaData(a_Player->GetYaw(), a_Player->GetPitch());
 		return true;
 	}
+	
+	virtual NIBBLETYPE MetaMirrorXZ(NIBBLETYPE a_Meta) override
+	{
+		// Bit 0x08 is a flag. Lowest three bits are position. 0x08 == 1000
+		NIBBLETYPE OtherMeta = a_Meta & 0x08;
+		// Mirrors defined by by a table. (Source, mincraft.gamepedia.com) 0x07 == 0111
+		switch (a_Meta & 0x07)
+		{
+			case 0x00: return 0x01 + OtherMeta; // Down -> Up
+			case 0x01: return 0x00 + OtherMeta; // Up -> Down
+		}
+		// Not Facing Up or Down; No change.
+		return a_Meta;
+	}
 } ;
 
 
diff --git a/src/Blocks/BlockEnderchest.h b/src/Blocks/BlockEnderchest.h
index b4b0b995d..97cf484fb 100644
--- a/src/Blocks/BlockEnderchest.h
+++ b/src/Blocks/BlockEnderchest.h
@@ -2,17 +2,17 @@
 #pragma once
 
 #include "BlockEntity.h"
-
+#include "MetaRotater.h"
 
 
 
 
 class cBlockEnderchestHandler :
-	public cBlockEntityHandler
+	public cMetaRotater<cBlockEntityHandler, 0x07, 0x02, 0x05, 0x03, 0x04>
 {
 public:
 	cBlockEnderchestHandler(BLOCKTYPE a_BlockType)
-		: cBlockEntityHandler(a_BlockType)
+		: cMetaRotater<cBlockEntityHandler, 0x07, 0x02, 0x05, 0x03, 0x04>(a_BlockType)
 	{
 	}
 
diff --git a/src/Blocks/BlockFenceGate.h b/src/Blocks/BlockFenceGate.h
index 1abe1eecf..e3162bbd6 100644
--- a/src/Blocks/BlockFenceGate.h
+++ b/src/Blocks/BlockFenceGate.h
@@ -2,17 +2,17 @@
 #pragma once
 
 #include "BlockHandler.h"
-
+#include "MetaRotater.h"
 
 
 
 
 class cBlockFenceGateHandler :
-	public cBlockHandler
+	public cMetaRotater<cBlockHandler, 0x03, 0x02, 0x03, 0x00, 0x01, true>
 {
 public:
 	cBlockFenceGateHandler(BLOCKTYPE a_BlockType) :
-		cBlockHandler(a_BlockType)
+		cMetaRotater<cBlockHandler, 0x03, 0x02, 0x03, 0x00, 0x01, true>(a_BlockType)
 	{
 	}
 
diff --git a/src/Blocks/BlockStairs.h b/src/Blocks/BlockStairs.h
index 93035b3b1..ea8405597 100644
--- a/src/Blocks/BlockStairs.h
+++ b/src/Blocks/BlockStairs.h
@@ -2,17 +2,17 @@
 #pragma once
 
 #include "BlockHandler.h"
-
+#include "MetaRotater.h"
 
 
 
 
 class cBlockStairsHandler :
-	public cBlockHandler
+	public cMetaRotater<cBlockHandler, 0x03, 0x03, 0x00, 0x02, 0x01, true>
 {
 public:
 	cBlockStairsHandler(BLOCKTYPE a_BlockType) :
-		cBlockHandler(a_BlockType)
+		cMetaRotater<cBlockHandler, 0x03, 0x03, 0x00, 0x02, 0x01, true>(a_BlockType)
 	{
 
 	}
@@ -104,54 +104,6 @@ public:
 	}
 
 
-	virtual NIBBLETYPE MetaRotateCCW(NIBBLETYPE a_Meta) override
-	{
-		// Bits 3 and 4 stay, the rest is swapped around according to a table:
-		NIBBLETYPE TopBits = (a_Meta & 0x0c);
-		switch (a_Meta & 0x03)
-		{
-			case 0x00: return TopBits | 0x03;  // East -> North
-			case 0x01: return TopBits | 0x02;  // West -> South
-			case 0x02: return TopBits | 0x00;  // South -> East
-			case 0x03: return TopBits | 0x01;  // North -> West
-		}
-		// Not reachable, but to avoid a compiler warning:
-		return 0;
-	}
-
-
-	virtual NIBBLETYPE MetaRotateCW(NIBBLETYPE a_Meta) override
-	{
-		// Bits 3 and 4 stay, the rest is swapped around according to a table:
-		NIBBLETYPE TopBits = (a_Meta & 0x0c);
-		switch (a_Meta & 0x03)
-		{
-			case 0x00: return TopBits | 0x02;  // East -> South
-			case 0x01: return TopBits | 0x03;  // West -> North
-			case 0x02: return TopBits | 0x01;  // South -> West
-			case 0x03: return TopBits | 0x00;  // North -> East
-		}
-		// Not reachable, but to avoid a compiler warning:
-		return 0;
-	}
-
-
-	virtual NIBBLETYPE MetaMirrorXY(NIBBLETYPE a_Meta) override
-	{
-		// Bits 3 and 4 stay, the rest is swapped around according to a table:
-		NIBBLETYPE TopBits = (a_Meta & 0x0c);
-		switch (a_Meta & 0x03)
-		{
-			case 0x00: return TopBits | 0x00;  // East -> East
-			case 0x01: return TopBits | 0x01;  // West -> West
-			case 0x02: return TopBits | 0x03;  // South -> North
-			case 0x03: return TopBits | 0x02;  // North -> South
-		}
-		// Not reachable, but to avoid a compiler warning:
-		return 0;
-	}
-
-
 	virtual NIBBLETYPE MetaMirrorXZ(NIBBLETYPE a_Meta) override
 	{
 		// Toggle bit 3:
@@ -159,20 +111,6 @@ public:
 	}
 
 
-	virtual NIBBLETYPE MetaMirrorYZ(NIBBLETYPE a_Meta) override
-	{
-		// Bits 3 and 4 stay, the rest is swapped around according to a table:
-		NIBBLETYPE TopBits = (a_Meta & 0x0c);
-		switch (a_Meta & 0x03)
-		{
-			case 0x00: return TopBits | 0x01;  // East -> West
-			case 0x01: return TopBits | 0x00;  // West -> East
-			case 0x02: return TopBits | 0x02;  // South -> South
-			case 0x03: return TopBits | 0x03;  // North -> North
-		}
-		// Not reachable, but to avoid a compiler warning:
-		return 0;
-	}
 } ;
 
 
diff --git a/src/Blocks/BlockTorch.h b/src/Blocks/BlockTorch.h
index 84bbb37ec..d32c77629 100644
--- a/src/Blocks/BlockTorch.h
+++ b/src/Blocks/BlockTorch.h
@@ -2,17 +2,17 @@
 
 #include "BlockHandler.h"
 #include "../Chunk.h"
-
+#include "MetaRotater.h"
 
 
 
 
 class cBlockTorchHandler :
-	public cBlockHandler
+	public cMetaRotater<cBlockHandler, 0x7, 0x4, 0x1, 0x3, 0x2>
 {
 public:
 	cBlockTorchHandler(BLOCKTYPE a_BlockType)
-		: cBlockHandler(a_BlockType)
+		: cMetaRotater<cBlockHandler, 0x7, 0x4, 0x1, 0x3, 0x2>(a_BlockType)
 	{
 	}
 	
@@ -185,67 +185,6 @@ public:
 	{
 		return "step.wood";
 	}
-	
-	
-	virtual NIBBLETYPE MetaRotateCCW(NIBBLETYPE a_Meta) override
-	{
-		// Bit 4 stays, the rest is swapped around according to a table:
-		NIBBLETYPE TopBits = (a_Meta & 0x08);
-		switch (a_Meta & 0x07)
-		{
-			case 0x01: return TopBits | 0x04;  // East  -> North
-			case 0x02: return TopBits | 0x03;  // West  -> South
-			case 0x03: return TopBits | 0x01;  // South -> East
-			case 0x04: return TopBits | 0x02;  // North -> West
-			default:   return a_Meta;          // Floor -> Floor
-		}
-	}
-
-
-	virtual NIBBLETYPE MetaRotateCW(NIBBLETYPE a_Meta) override
-	{
-		// Bit 4 stays, the rest is swapped around according to a table:
-		NIBBLETYPE TopBits = (a_Meta & 0x08);
-		switch (a_Meta & 0x07)
-		{
-			case 0x01: return TopBits | 0x03;  // East  -> South
-			case 0x02: return TopBits | 0x04;  // West  -> North
-			case 0x03: return TopBits | 0x02;  // South -> West
-			case 0x04: return TopBits | 0x01;  // North -> East
-			default:   return a_Meta;          // Floor -> Floor
-		}
-	}
-
-
-	virtual NIBBLETYPE MetaMirrorXY(NIBBLETYPE a_Meta) override
-	{
-		// Bit 4 stays, the rest is swapped around according to a table:
-		NIBBLETYPE TopBits = (a_Meta & 0x08);
-		switch (a_Meta & 0x07)
-		{
-			case 0x03: return TopBits | 0x04;  // South -> North
-			case 0x04: return TopBits | 0x03;  // North -> South
-			default:   return a_Meta;          // Keep the rest
-		}
-	}
-
-
-	// Mirroring around the XZ plane doesn't make sense for floor torches,
-	// the others stay the same, so let's keep all the metas the same.
-	// The base class does tht for us, no need to override MetaMirrorXZ()
-
-	
-	virtual NIBBLETYPE MetaMirrorYZ(NIBBLETYPE a_Meta) override
-	{
-		// Bit 4 stays, the rest is swapped around according to a table:
-		NIBBLETYPE TopBits = (a_Meta & 0x08);
-		switch (a_Meta & 0x07)
-		{
-			case 0x01: return TopBits | 0x02;  // East -> West
-			case 0x02: return TopBits | 0x01;  // West -> East
-			default:   return a_Meta;          // Keep the rest
-		}
-	}
 } ;
 
 
diff --git a/src/Blocks/BlockVine.h b/src/Blocks/BlockVine.h
index 0934a451b..708583e70 100644
--- a/src/Blocks/BlockVine.h
+++ b/src/Blocks/BlockVine.h
@@ -1,8 +1,7 @@
-
 #pragma once
 
 #include "BlockHandler.h"
-
+#include "MetaRotater.h"
 
 
 
@@ -190,8 +189,8 @@ public:
 	{
 		return ((a_Meta << 1) | (a_Meta >> 3)) & 0x0f;  // Rotate bits to the left
 	}
-	
-	
+
+
 	virtual NIBBLETYPE MetaMirrorXY(NIBBLETYPE a_Meta) override
 	{
 		// Bits 2 and 4 stay, bits 1 and 3 swap
@@ -204,6 +203,7 @@ public:
 		// Bits 1 and 3 stay, bits 2 and 4 swap
 		return ((a_Meta & 0x05) | ((a_Meta & 0x02) << 2) | ((a_Meta & 0x08) >> 2));
 	}
+
 } ;
 
 
diff --git a/src/Blocks/MetaRotater.h b/src/Blocks/MetaRotater.h
new file mode 100644
index 000000000..dde88e6db
--- /dev/null
+++ b/src/Blocks/MetaRotater.h
@@ -0,0 +1,120 @@
+// MetaRotater.h
+
+// Provides a mixin for rotations and reflections
+
+#pragma once
+
+// MSVC generates warnings for the templated AssertIfNotMatched parameter conditions, so disable it:
+#ifdef _MSC_VER
+	#pragma warning(disable: 4127) // Conditional expression is constant
+#endif
+
+
+
+
+
+/*
+Provides a mixin for rotations and reflections following the standard pattern of apply mask then use case.
+
+Usage:
+Inherit from this class providing your base class as Base, the BitMask for the direction bits in bitmask and the masked value for the directions in North, East, South, West. There is also an aptional parameter AssertIfNotMatched. Set this if it is invalid for a block to exist in any other state.
+*/
+
+template<class Base, NIBBLETYPE BitMask, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West, bool AssertIfNotMatched = false>
+class cMetaRotater : public Base
+{
+public:
+
+	cMetaRotater(BLOCKTYPE a_BlockType) :
+		Base(a_BlockType)
+	{}
+	
+	virtual ~cMetaRotater() {}
+
+	virtual NIBBLETYPE MetaRotateCCW(NIBBLETYPE a_Meta)  override;
+	virtual NIBBLETYPE MetaRotateCW(NIBBLETYPE a_Meta)  override;
+	virtual NIBBLETYPE MetaMirrorXY(NIBBLETYPE a_Meta)  override;
+	virtual NIBBLETYPE MetaMirrorYZ(NIBBLETYPE a_Meta)  override;
+};
+
+
+
+
+
+template<class Base, NIBBLETYPE BitMask, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West, bool AssertIfNotMatched>
+NIBBLETYPE cMetaRotater<Base, BitMask, North, East, South, West, AssertIfNotMatched>::MetaRotateCW(NIBBLETYPE a_Meta)
+{
+	NIBBLETYPE OtherMeta = a_Meta & (~BitMask);
+	switch (a_Meta & BitMask)
+	{
+		case South: return West  | OtherMeta; 
+		case West:  return North | OtherMeta; 
+		case North: return East  | OtherMeta;
+		case East:  return South | OtherMeta;
+	}
+	if (AssertIfNotMatched)
+	{
+		ASSERT(!"Invalid Meta value");
+	}
+	return a_Meta;
+}
+
+
+
+
+
+template<class Base, NIBBLETYPE BitMask, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West, bool AssertIfNotMatched>
+NIBBLETYPE cMetaRotater<Base, BitMask, North, East, South, West, AssertIfNotMatched>::MetaRotateCCW(NIBBLETYPE a_Meta)
+{
+	NIBBLETYPE OtherMeta = a_Meta & (~BitMask);
+	switch (a_Meta & BitMask)
+	{
+		case South: return East  | OtherMeta; 
+		case East:  return North | OtherMeta;
+		case North: return West  | OtherMeta;
+		case West:  return South | OtherMeta;
+	}
+	if (AssertIfNotMatched)
+	{
+		ASSERT(!"Invalid Meta value");
+	}
+	return a_Meta;
+}
+
+
+
+
+
+template<class Base, NIBBLETYPE BitMask, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West, bool AssertIfNotMatched>
+NIBBLETYPE cMetaRotater<Base, BitMask, North, East, South, West, AssertIfNotMatched>::MetaMirrorXY(NIBBLETYPE a_Meta)
+{
+	NIBBLETYPE OtherMeta = a_Meta & (~BitMask);
+	switch (a_Meta & BitMask)
+	{
+		case South: return North | OtherMeta;
+		case North: return South | OtherMeta;
+	}
+	// Not Facing North or South; No change.
+	return a_Meta;
+}
+
+
+
+
+
+template<class Base, NIBBLETYPE BitMask, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West, bool AssertIfNotMatched>
+NIBBLETYPE cMetaRotater<Base, BitMask, North, East, South, West, AssertIfNotMatched>::MetaMirrorYZ(NIBBLETYPE a_Meta)
+{
+	NIBBLETYPE OtherMeta = a_Meta & (~BitMask);
+	switch (a_Meta & BitMask)
+	{
+		case West: return East | OtherMeta;
+		case East: return West | OtherMeta;
+	}
+	// Not Facing East or West; No change.
+	return a_Meta;
+}
+
+
+
+