Pitch is specified in bytes and always byte aligned. Fixes issue 168.

src/nvtt/CompressionOptions.cpp

@@ -63,7 +63,7 @@ void CompressionOptions::reset()
     m.asize = 8;
 	
     m.pixelType = PixelType_UnsignedNorm;
-    m.pitchAlignment = 8;
+    m.pitchAlignment = 1;
 
     m.enableColorDithering = false;
     m.enableAlphaDithering = false;

src/nvtt/CompressorRGB.cpp

@@ -188,12 +188,11 @@ void PixelFormatConverter::compress(nvtt::AlphaMode /*alphaMode*/, uint w, uint
         }
     }
 
-    const uint pitch = computeBitPitch(w, bitCount, compressionOptions.pitchAlignment);
-    const uint pitchInBytes = (pitch + 7) / 8;
+    const uint pitch = computeBytePitch(w, bitCount, compressionOptions.pitchAlignment);
     const uint wh = w * h;
 
     // Allocate output scanline.
-    uint8 * const dst = malloc<uint8>(pitchInBytes);
+    uint8 * const dst = malloc<uint8>(pitch);
 
     for (uint y = 0; y < h; y++)
     {
@@ -252,15 +251,15 @@ void PixelFormatConverter::compress(nvtt::AlphaMode /*alphaMode*/, uint w, uint
 
         // Zero padding.
         stream.align(compressionOptions.pitchAlignment);
-        nvDebugCheck(stream.ptr == dst + pitchInBytes);
+        nvDebugCheck(stream.ptr == dst + pitch);
 
-        /*for (uint x = w * byteCount; x < pitchInBytes; x++)
+        /*for (uint x = w * byteCount; x < pitch; x++)
         {
                 *(dst + x) = 0;
         }*/
 
         // @@ This code does not truly support less than byte-aligned textures.
-        outputOptions.writeData(dst, pitchInBytes);
+        outputOptions.writeData(dst, pitch);
     }
 
     free(dst);

src/nvtt/TexImage.cpp

@@ -109,10 +109,10 @@ uint nv::countMipmaps(uint w, uint h, uint d)
     return mipmap + 1;
 }
 
-uint nv::computeImageSize(uint w, uint h, uint d, uint bitCount, uint pitchAlignmentInBits, Format format)
+uint nv::computeImageSize(uint w, uint h, uint d, uint bitCount, uint pitchAlignmentInBytes, Format format)
 {
     if (format == Format_RGBA) {
-        return d * h * computeBytePitch(w, bitCount, pitchAlignmentInBits);
+        return d * h * computeBytePitch(w, bitCount, pitchAlignmentInBytes);
     }
     else {
         // @@ Handle 3D textures. DXT and VTC have different behaviors.

src/nvtt/TexImage.h

@@ -79,7 +79,7 @@ namespace nvtt
 
 namespace nv {
     uint countMipmaps(uint w, uint h, uint d);
-    uint computeImageSize(uint w, uint h, uint d, uint bitCount, uint alignment, nvtt::Format format);
+    uint computeImageSize(uint w, uint h, uint d, uint bitCount, uint alignmentInBytes, nvtt::Format format);
     void getTargetExtent(int & w, int & h, int & d, int maxExtent, nvtt::RoundMode roundMode, nvtt::TextureType textureType);
 }