Function CompressMasked

Engine/lib/squish/squish.cpp:59–123

}

void CompressMasked( u8 const* rgba, int mask, void* block, int flags, float* metric )
{
	// fix any bad flags
	flags = FixFlags( flags );

	if ( ( flags & ( kBc4 | kBc5 ) ) != 0 )
	{
		u8 alpha[16*4];
		for( int i = 0; i < 16; ++i )
		{
			alpha[i*4 + 3] = rgba[i*4 + 0]; // copy R to A
		}

		u8* rBlock = reinterpret_cast< u8* >( block );
		CompressAlphaDxt5( alpha, mask, rBlock );

		if ( ( flags & ( kBc5 ) ) != 0 )
		{
			for( int i = 0; i < 16; ++i )
			{
				alpha[i*4 + 3] = rgba[i*4 + 1]; // copy G to A
			}

			u8* gBlock = reinterpret_cast< u8* >( block ) + 8;
			CompressAlphaDxt5( alpha, mask, gBlock );
		}

		return;
	}

	// get the block locations
	void* colourBlock = block;
	void* alphaBlock = block;
	if( ( flags & ( kDxt3 | kDxt5 ) ) != 0 )
		colourBlock = reinterpret_cast< u8* >( block ) + 8;

	// create the minimal point set
	ColourSet colours( rgba, mask, flags );
	
	// check the compression type and compress colour
	if( colours.GetCount() == 1 )
	{
		// always do a single colour fit
		SingleColourFit fit( &colours, flags );
		fit.Compress( colourBlock );
	}
	else if( ( flags & kColourRangeFit ) != 0 || colours.GetCount() == 0 )
	{
		// do a range fit
		RangeFit fit( &colours, flags, metric );
		fit.Compress( colourBlock );
	}
	else
	{
		// default to a cluster fit (could be iterative or not)
		ClusterFit fit( &colours, flags, metric );
		fit.Compress( colourBlock );
	}