Move ClassicFacingFudge support to Mods.Cnc

This moves the TD/RA-specific re-mapping of sprite facings
and coordinates to Mods.Cnc.

OpenRA.Mods.Cnc/Util.cs

@@ -0,0 +1,40 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+namespace OpenRA.Mods.Cnc
+{
+	public static class Util
+	{
+		public static int ClassicQuantizeFacing(int facing, int numFrames, bool useClassicFacingFudge)
+		{
+			if (!useClassicFacingFudge || numFrames != 32)
+				return OpenRA.Mods.Common.Util.QuantizeFacing(facing, numFrames);
+
+			// TD and RA divided the facing artwork into 3 frames from (north|south) to (north|south)-(east|west)
+			// and then 5 frames from (north|south)-(east|west) to (east|west)
+			var quadrant = ((facing + 31) & 0xFF) / 64;
+			if (quadrant == 0 || quadrant == 2)
+			{
+				var frame = OpenRA.Mods.Common.Util.QuantizeFacing(facing, 24);
+				if (frame > 18)
+					return frame + 6;
+				if (frame > 4)
+					return frame + 3;
+				return frame;
+			}
+			else
+			{
+				var frame = OpenRA.Mods.Common.Util.QuantizeFacing(facing, 40);
+				return frame < 20 ? frame - 3 : frame - 8;
+			}
+		}
+	}
+}