Integrate YCoCg color space conversion by Jim Tilander.

src/nvtt/Compressor.cpp

@@ -34,6 +34,7 @@
 #include <nvimage/Filter.h>
 #include <nvimage/Quantize.h>
 #include <nvimage/NormalMap.h>
+#include <nvimage/ColorSpace.h>
 
 #include "Compressor.h"
 #include "InputOptions.h"
@@ -482,6 +483,17 @@ bool Compressor::Private::initMipmap(Mipmap & mipmap, const InputOptions::Privat
 		premultiplyAlphaMipmap(mipmap, inputOptions);
 	}
 
+	// Apply gamma space color transforms:
+	if (inputOptions.colorTransform == ColorTransform_YCoCg)
+	{
+		ColorSpace::RGBtoYCoCg_R(mipmap.asMutableFixedImage());
+	}
+	else if (inputOptions.colorTransform == ColorTransform_ScaledYCoCg)
+	{
+		// @@ TODO
+		//ColorSpace::RGBtoYCoCg_R(mipmap.asMutableFixedImage());
+	}
+
 	return true;
 }
 

src/nvtt/nvtt.h

@@ -156,8 +156,10 @@ namespace nvtt
 	enum ColorTransform
 	{
 		ColorTransform_None,
-		ColorTransform_Linear,
-		ColorTransform_Swizzle
+		ColorTransform_Linear,      ///< Not implemented.
+		ColorTransform_Swizzle,     ///< Not implemented.
+		ColorTransform_YCoCg,       ///< Transform into r=Co, g=Cg, b=0, a=Y
+		ColorTransform_ScaledYCoCg, ///< Not implemented.
 	};
 	
 	/// Extents rounding mode.