Add target decoder compression option.

src/nvtt/CompressionOptions.cpp

@@ -69,6 +69,8 @@ void CompressionOptions::reset()
     m.enableAlphaDithering = false;
     m.binaryAlpha = false;
     m.alphaThreshold = 127;
+
+    m.decoder = Decoder_D3D10;
 }
 
 
@@ -185,6 +187,13 @@ void CompressionOptions::setQuantization(bool colorDithering, bool alphaDitherin
     m.alphaThreshold = alphaThreshold;
 }
 
+/// Set target decoder to optimize for.
+void CompressionOptions::setTargetDecoder(Decoder decoder)
+{
+    m.decoder = decoder;
+}
+
+
 
 // Translate to and from D3D formats.
 unsigned int CompressionOptions::d3d9Format() const

src/nvtt/CompressionOptions.h

@@ -62,6 +62,8 @@ namespace nvtt
         bool binaryAlpha;
         int alphaThreshold;			// reference value used for binary alpha quantization.
 
+        Decoder decoder;
+
         uint getBitCount() const
         {
             if (format == Format_RGBA) {

src/nvtt/nvtt.h

@@ -121,6 +121,15 @@ namespace nvtt
         Quality_Highest,
     };
 
+    /// DXT decoder.
+    enum Decoder
+    {
+        Decoder_D3D10,
+        Decoder_D3D9,
+        Decoder_NV5x,
+    };
+
+
     /// Compression options. This class describes the desired compression format and other compression settings.
     struct CompressionOptions
     {
@@ -148,6 +157,8 @@ namespace nvtt
 
         NVTT_API void setQuantization(bool colorDithering, bool alphaDithering, bool binaryAlpha, int alphaThreshold = 127);
 
+        NVTT_API void setTargetDecoder(Decoder decoder);
+
         // Translate to and from D3D formats.
         NVTT_API unsigned int d3d9Format() const;
         //NVTT_API bool setD3D9Format(unsigned int format);
@@ -377,14 +388,6 @@ namespace nvtt
     typedef Compressor Context;
 
 
-    /// DXT decoder.
-    enum Decoder
-    {
-        Decoder_D3D10,
-        Decoder_D3D9,
-        Decoder_NV5x,
-    };
-
     /// A texture mipmap.
     struct TexImage
     {