KTX ASTC Support

I removed some vestiges of ASTC support in DDS, and fixed a few math bugs regarding pixel sizes and compressed size for astc.
Also, we don't try to invert ASTC KTX textures becaue they're fed to opengl correctly as long as the origin is set accurately.

Author: bmdhacks

src/osg/Image.cpp

@@ -806,15 +806,15 @@ unsigned int Image::computePixelSizeInBits(GLenum format,GLenum type)
         {
             osg::Vec3i footprint = computeBlockFootprint(format);
             unsigned int pixelsPerBlock = footprint.x() * footprint.y();
-            unsigned int bitsPerBlock = computeBlockSize(format, 0);//16 x 8 = 128
+            unsigned int bitsPerBlock = computeBlockSize(format, 0) * 8; // Convert bytes to bits
             unsigned int bitsPerPixel = bitsPerBlock / pixelsPerBlock;
             if (bitsPerBlock == bitsPerPixel * pixelsPerBlock) {
-                OSG_WARN << "Image::computePixelSizeInBits(format,type) : bits per pixel (" << bitsPerPixel << ") is not an integer for GL_KHR_texture_compression_astc_hdr sizes other than 4x4 and 8x8." << std::endl;
+                // Integer division worked perfectly
                 return bitsPerPixel;
             } else {
                 OSG_WARN << "Image::computePixelSizeInBits(format,type) : bits per pixel (" << bitsPerBlock << "/" << pixelsPerBlock << ") is not an integer for GL_KHR_texture_compression_astc_hdr size" << footprint.x()  << "x" << footprint.y() << "." << std::endl;
+                return 0;
             }
-            return 0;
         }
         default: break;
     }
@@ -1827,6 +1827,8 @@ void Image::flipVertical()
 
     const bool dxtc(dxtc_tool::isDXTC(_pixelFormat));
     const bool rgtc(dxtc_tool::isRGTC(_pixelFormat));
+    const bool astc(isCompressed() && (_pixelFormat >= GL_COMPRESSED_RGBA_ASTC_4x4_KHR && _pixelFormat <= GL_COMPRESSED_SRGB8_ALPHA8_ASTC_12x12_KHR));
+
     if (_mipmapData.empty())
     {
         // no mipmaps,
@@ -1840,9 +1842,10 @@ void Image::flipVertical()
                     OSG_NOTICE << "Notice Image::flipVertical(): Vertical flip do not succeed" << std::endl;
                 }
             }
-            else
+            // ASTC textures are stored in KTX format with native OpenGL orientation - skip flipping
+            else if (!astc)
             {
-                if (isCompressed()) OSG_NOTICE << "Notice Image::flipVertical(): image is compressed but normal v-flip is used" << std::endl;
+                if (isCompressed()) OSG_NOTICE << "Notice Image::flipVertical(): file=" << _fileName << " image is compressed but normal v-flip is used" << std::endl;
                 // its not a compressed image, so implement flip oursleves.
                 unsigned char* top = data(0,0,r);
                 unsigned char* bottom = top + (_t-1)*rowStep;
@@ -1887,7 +1890,8 @@ void Image::flipVertical()
                     OSG_NOTICE << "Notice Image::flipVertical(): Vertical flip did not succeed" << std::endl;
                 }
             }
-            else
+            // ASTC textures are stored in KTX format with native OpenGL orientation - skip flipping
+            else if (!astc)
             {
                 // it's not a compressed image, so implement flip ourselves.
                 unsigned int mipRowSize = computeRowWidthInBytes(s, _pixelFormat, _dataType, _packing);

src/osg/Texture.cpp

@@ -1995,85 +1995,85 @@ void Texture::getCompressedSize(GLenum internalFormat, GLint width, GLint height
     else if (internalFormat == GL_COMPRESSED_RGBA_ASTC_4x4_KHR || internalFormat == GL_COMPRESSED_SRGB8_ALPHA8_ASTC_4x4_KHR)
     {
         blockSize = 16;
-        size = ceil(width/4.0)*ceil(height/4.0)*blockSize;
+        size = ((width+3)/4)*((height+3)/4)*depth*blockSize;
         return;
     }
     else if (internalFormat == GL_COMPRESSED_RGBA_ASTC_5x4_KHR || internalFormat == GL_COMPRESSED_SRGB8_ALPHA8_ASTC_5x4_KHR)
     {
         blockSize = 16;
-        size = ceil(width/5.0)*ceil(height/4.0)*blockSize;
+        size = ((width+4)/5)*((height+3)/4)*depth*blockSize;
         return;
     }
     else if (internalFormat == GL_COMPRESSED_RGBA_ASTC_5x5_KHR || internalFormat == GL_COMPRESSED_SRGB8_ALPHA8_ASTC_5x5_KHR)
     {
         blockSize = 16;
-        size = ceil(width/5.0)*ceil(height/5.0)*blockSize;
+        size = ((width+4)/5)*((height+4)/5)*depth*blockSize;
         return;
     }
     else if (internalFormat == GL_COMPRESSED_RGBA_ASTC_6x5_KHR || internalFormat == GL_COMPRESSED_SRGB8_ALPHA8_ASTC_6x5_KHR)
     {
         blockSize = 16;
-        size = ceil(width/6.0)*ceil(height/5.0)*blockSize;
+        size = ((width+5)/6)*((height+4)/5)*depth*blockSize;
         return;
     }
     else if (internalFormat == GL_COMPRESSED_RGBA_ASTC_6x6_KHR || internalFormat == GL_COMPRESSED_SRGB8_ALPHA8_ASTC_6x6_KHR)
     {
         blockSize = 16;
-        size = ceil(width/6.0)*ceil(height/6.0)*blockSize;
+        size = ((width+5)/6)*((height+5)/6)*depth*blockSize;
         return;
     }
     else if (internalFormat == GL_COMPRESSED_RGBA_ASTC_8x5_KHR || internalFormat == GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8x5_KHR)
     {
         blockSize = 16;
-        size = ceil(width/8.0)*ceil(height/5.0)*blockSize;
+        size = ((width+7)/8)*((height+4)/5)*depth*blockSize;
         return;
     }
     else if (internalFormat == GL_COMPRESSED_RGBA_ASTC_8x6_KHR || internalFormat == GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8x6_KHR)
     {
         blockSize = 16;
-        size = ceil(width/8.0)*ceil(height/6.0)*blockSize;
+        size = ((width+7)/8)*((height+5)/6)*depth*blockSize;
         return;
     }
     else if (internalFormat == GL_COMPRESSED_RGBA_ASTC_8x8_KHR || internalFormat == GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8x8_KHR)
     {
         blockSize = 16;
-        size = ceil(width/8.0)*ceil(height/8.0)*blockSize;
+        size = ((width+7)/8)*((height+7)/8)*depth*blockSize;
         return;
     }
     else if (internalFormat == GL_COMPRESSED_RGBA_ASTC_10x5_KHR || internalFormat == GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x5_KHR)
     {
         blockSize = 16;
-        size = ceil(width/10.0)*ceil(height/5.0)*blockSize;
+        size = ((width+9)/10)*((height+4)/5)*depth*blockSize;
         return;
     }
     else if (internalFormat == GL_COMPRESSED_RGBA_ASTC_10x6_KHR || internalFormat == GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x6_KHR)
     {
         blockSize = 16;
-        size = ceil(width/10.0)*ceil(height/6.0)*blockSize;
+        size = ((width+9)/10)*((height+5)/6)*depth*blockSize;
         return;
     }
     else if (internalFormat == GL_COMPRESSED_RGBA_ASTC_10x8_KHR || internalFormat == GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x8_KHR)
     {
         blockSize = 16;
-        size = ceil(width/10.0)*ceil(height/8.0)*blockSize;
+        size = ((width+9)/10)*((height+7)/8)*depth*blockSize;
         return;
     }
     else if (internalFormat == GL_COMPRESSED_RGBA_ASTC_10x10_KHR || internalFormat == GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x10_KHR)
     {
         blockSize = 16;
-        size = ceil(width/10.0)*ceil(height/10.0)*blockSize;
+        size = ((width+9)/10)*((height+9)/10)*depth*blockSize;
         return;
     }
     else if (internalFormat == GL_COMPRESSED_RGBA_ASTC_12x10_KHR || internalFormat == GL_COMPRESSED_SRGB8_ALPHA8_ASTC_12x10_KHR)
     {
         blockSize = 16;
-        size = ceil(width/12.0)*ceil(height/10.0)*blockSize;
+        size = ((width+11)/12)*((height+9)/10)*depth*blockSize;
         return;
     }
     else if (internalFormat == GL_COMPRESSED_RGBA_ASTC_12x12_KHR || internalFormat == GL_COMPRESSED_SRGB8_ALPHA8_ASTC_12x12_KHR)
     {
         blockSize = 16;
-        size = ceil(width/12.0)*ceil(height/12.0)*blockSize;
+        size = ((width+11)/12)*((height+11)/12)*depth*blockSize;
         return;
     }
     else

src/osgPlugins/ktx/ReaderWriterKTX.cpp

@@ -210,6 +210,9 @@ osgDB::ReaderWriter::ReadResult ReaderWriterKTX::readKTXStream(std::istream& fin
         header.glInternalFormat, header.glFormat,
         header.glType, totalImageData, osg::Image::USE_NEW_DELETE);
 
+    // KTX textures are stored in their original coordinate system (TOP_LEFT)
+    image->setOrigin(osg::Image::TOP_LEFT);
+
     if (header.numberOfMipmapLevels > 1)
         image->setMipmapLevels(mipmapData);