Added in MetaMirrorXY and MetaMirrorYZ to cBlockSignHandler.

src/Blocks/BlockSign.h

@@ -83,6 +83,25 @@ public:
 	{
 		return (--a_Meta) & 0x0F;
 	}
+
+	virtual NIBBLETYPE MetaMirrorXY(NIBBLETYPE a_Meta) override
+	{
+		//  Mirrors signs over the XY plane (North-South Mirroring)
+
+		//  There are 16 meta values which correspond to different directions.
+		//  These values are equated to angles on a circle; 0x08 = 180 degrees.
+		return (a_Meta < 0x08) ? 0x08 + a_Meta : 0x08 - a_Meta;
+	}
+
+
+	virtual NIBBLETYPE MetaMirrorYZ(NIBBLETYPE a_Meta) override
+	{
+		//  Mirrors signs over the YZ plane (East-West Mirroring)
+
+		//  There are 16 meta values which correspond to different directions.
+		//  These values are equated to angles on a circle; 0x10 = 360 degrees.
+		return 0x10 - a_Meta;
+	}
 } ;