/// <summary>
/// Compresses a 4x4 block of pixels.
/// </summary>
/// <param name="rgba">The rgba values of the 16 source pixels.</param>
/// <param name="mask">The valid pixel mask.</param>
/// <param name="block">Storage for the compressed DXT block.</param>
/// <param name="flags">Compression flags.</param>
public static unsafe void CompressMasked(byte* rgba, int mask, byte* block, SquishFlags flags)
{
// fix any bad flags
flags = FixFlags(flags);
if ((flags & (SquishFlags.BC1 | SquishFlags.BC2 | SquishFlags.BC3 | SquishFlags.BC4 | SquishFlags.BC5)) != 0)
{
CompressMaskedBC(rgba, mask, block, flags);
return;
}
// get the block locations
byte* colourBlock = block;
byte* alphaBock = block;
if ((flags & (SquishFlags.Dxt3 | SquishFlags.Dxt5)) != 0)
colourBlock = block + 8;
// create the minimal point set
ColourSet colours = new ColourSet(rgba, mask, flags);
// check the compression type and compress colour
if (colours.GetCount() == 1)
{
// always do a single colour fit
SingleColourFit fit = new SingleColourFit(colours, flags);
fit.Compress(colourBlock);
}
else if ((flags & SquishFlags.ColourRangeFit) != 0 || colours.GetCount() == 0)
{
// do a range fit
RangeFit fit = new RangeFit(colours, flags);
fit.Compress(colourBlock);
}
else
{
// default to a cluster fit (could be iterative or not)
ClusterFit fit = new ClusterFit(colours, flags);
fit.Compress(colourBlock);
}
// compress alpha separately if necessary
if ((flags & SquishFlags.Dxt3) != 0)
AlphaBlock.CompressAlphaDxt3(rgba, mask, alphaBock);
else if ((flags & SquishFlags.Dxt5) != 0)
AlphaBlock.CompressAlphaDxt5(rgba, mask, alphaBock);
}
