Function LoadATI2

common/dds.cpp:721–773

}

static bool LoadATI2( QDataStream & s, const DDSHeader & header, QImage & img )
{
    const uint w = header.width;
    const uint h = header.height;

    BlockDXTAlphaLinear xblock;
    BlockDXTAlphaLinear yblock;
    QRgb * scanline[4];

    for( uint y = 0; y < h; y += 4 ) {
        for( uint j = 0; j < 4; j++ ) {
            scanline[j] = (QRgb *) img.scanLine( y + j );
        }
        for( uint x = 0; x < w; x += 4 ) {

            // Read 128bit color block.
            s >> xblock;
            s >> yblock;

            // Decode color block.
            uchar xblock_array[8];
            xblock.GetAlphas(xblock_array);

            uchar xbit_array[16];
            xblock.GetBits(xbit_array);

            uchar yblock_array[8];
            yblock.GetAlphas(yblock_array);

            uchar ybit_array[16];
            yblock.GetBits(ybit_array);

            // Write color block.
            for( uint j = 0; j < 4; j++ ) {
                for( uint i = 0; i < 4; i++ ) {
                    if( img.valid( x+i, y+j ) ) {
                        const uchar nx = xblock_array[xbit_array[j*4+i]];
                        const uchar ny = yblock_array[ybit_array[j*4+i]];

                        const float fx = float(nx) / 127.5f - 1.0f;
                        const float fy = float(ny) / 127.5f - 1.0f;
                        const float fz = sqrtf(1.0f - fx*fx - fy*fy);
                        const uchar nz = uchar((fz + 1.0f) * 127.5f);

                        scanline[j][x+i] = qRgb(nx, ny, nz);
                    }
                }
            }
        }
    }

    return true;
}