1 files changed, 133 insertions, 1 deletions

diff --git a/src/Blocks/BlockPiston.h b/src/Blocks/BlockPiston.h
index 7632b5e5a..e6fa48e54 100644
--- a/src/Blocks/BlockPiston.h
+++ b/src/Blocks/BlockPiston.h
@@ -21,6 +21,138 @@ public:
 		int a_CursorX, int a_CursorY, int a_CursorZ,
 		BLOCKTYPE & a_BlockType, NIBBLETYPE & a_BlockMeta
 	) override;
+
+	static NIBBLETYPE RotationPitchToMetaData(double a_Rotation, double a_Pitch)
+	{
+		if (a_Pitch >= 50)
+		{
+			return 0x1;
+		}
+		else if (a_Pitch <= -50)
+		{
+			return 0x0;
+		}
+		else
+		{
+			a_Rotation += 90 + 45;  // So its not aligned with axis
+
+			if (a_Rotation > 360)
+			{
+				a_Rotation -= 360;
+			}
+			if ((a_Rotation >= 0) && (a_Rotation < 90))
+			{
+				return 0x4;
+			}
+			else if ((a_Rotation >= 180) && (a_Rotation < 270))
+			{
+				return 0x5;
+			}
+			else if ((a_Rotation >= 90) && (a_Rotation < 180))
+			{
+				return 0x2;
+			}
+			else
+			{
+				return 0x3;
+			}
+		}
+	}
+
+	static eBlockFace MetaDataToDirection(NIBBLETYPE a_MetaData)
+	{
+		switch (a_MetaData)
+		{
+			case 0x0: return BLOCK_FACE_YM;
+			case 0x1: return BLOCK_FACE_YP;
+			case 0x2: return BLOCK_FACE_ZM;
+			case 0x3: return BLOCK_FACE_ZP;
+			case 0x4: return BLOCK_FACE_XM;
+			case 0x5: return BLOCK_FACE_XP;
+			default:
+			{
+				ASSERT(!"Invalid Metadata");
+				return BLOCK_FACE_NONE;
+			}
+		}
+	}	
+
+	static void ExtendPiston(int a_BlockX, int a_BlockY, int a_BlockZ, cWorld * a_World);
+	static void RetractPiston(int a_BlockX, int a_BlockY, int a_BlockZ, cWorld * a_World);
+
+private:
+
+	/// Returns true if the piston (specified by blocktype) is a sticky piston
+	static inline bool IsSticky(BLOCKTYPE a_BlockType) { return (a_BlockType == E_BLOCK_STICKY_PISTON); }
+
+	/// Returns true if the piston (with the specified meta) is extended
+	static inline bool IsExtended(NIBBLETYPE a_PistonMeta) { return ((a_PistonMeta & 0x8) != 0x0); }
+
+	/// Returns true if the specified block can be pushed by a piston (and left intact)
+	static inline bool CanPush(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta)
+	{
+		switch (a_BlockType)
+		{
+			case E_BLOCK_ANVIL:
+			case E_BLOCK_BED:
+			case E_BLOCK_BEDROCK:
+			case E_BLOCK_BREWING_STAND:
+			case E_BLOCK_CHEST:
+			case E_BLOCK_COMMAND_BLOCK:
+			case E_BLOCK_DISPENSER:
+			case E_BLOCK_DROPPER:
+			case E_BLOCK_ENCHANTMENT_TABLE:
+			case E_BLOCK_END_PORTAL:
+			case E_BLOCK_END_PORTAL_FRAME:
+			case E_BLOCK_FURNACE:
+			case E_BLOCK_LIT_FURNACE:
+			case E_BLOCK_HOPPER:
+			case E_BLOCK_JUKEBOX:
+			case E_BLOCK_MOB_SPAWNER:
+			case E_BLOCK_NETHER_PORTAL:
+			case E_BLOCK_NOTE_BLOCK:
+			case E_BLOCK_OBSIDIAN:
+			case E_BLOCK_PISTON_EXTENSION:
+			{
+				return false;
+			}
+			case E_BLOCK_STICKY_PISTON:
+			case E_BLOCK_PISTON:
+			{
+				// A piston can only be pushed if retracted:
+				return !IsExtended(a_BlockMeta);
+			}
+		}
+		return true;
+	}
+
+	/// Returns true if the specified block can be pushed by a piston and broken / replaced
+	static inline bool CanBreakPush(BLOCKTYPE a_BlockType) { return cBlockInfo::IsPistonBreakable(a_BlockType); }
+
+	/// Returns true if the specified block can be pulled by a sticky piston
+	static inline bool CanPull(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta)
+	{
+		switch (a_BlockType)
+		{
+			case E_BLOCK_LAVA:
+			case E_BLOCK_STATIONARY_LAVA:
+			case E_BLOCK_STATIONARY_WATER:
+			case E_BLOCK_WATER:
+			{
+				return false;
+			}
+		}
+
+		if (CanBreakPush(a_BlockType))
+		{
+			return false; // CanBreakPush returns true, but we need false to prevent pulling
+		}
+		
+		return CanPush(a_BlockType, a_BlockMeta);
+	}
+
+	/// Returns how many blocks the piston has to push (where the first free space is); < 0 when unpushable
+	static int FirstPassthroughBlock(int a_PistonX, int a_PistonY, int a_PistonZ, NIBBLETYPE a_PistonMeta, cWorld * a_World);
 } ;
 
 
@@ -40,7 +172,7 @@ public:
 	virtual void ConvertToPickups(cItems & a_Pickups, NIBBLETYPE a_BlockMeta) override
 	{
 		// No pickups
-		// Also with 1.7, the item forms of these tecnical blocks have been removed, so giving someone this will crash their client...
+		// Also with 1.7, the item forms of these technical blocks have been removed, so giving someone this will crash their client...
 	}
 } ;