private static Bc4Block FindRedValues(Bc4Block colorBlock, byte[] pixels, int variations)
{
//Find min and max alpha
byte min = 255;
byte max = 0;
bool hasExtremeValues = false;
for (int i = 0; i < pixels.Length; i++)
{
if (pixels[i] < 255 && pixels[i] > 0)
{
if (pixels[i] < min)
{
min = pixels[i];
}
if (pixels[i] > max)
{
max = pixels[i];
}
}
else
{
hasExtremeValues = true;
}
}
int SelectIndices(ref Bc4Block block)
{
int cumulativeError = 0;
var c0 = block.Red0;
var c1 = block.Red1;
Span <byte> colors = c0 > c1
? stackalloc byte[] {
private Bc4Block EncodeBlock(RawBlock4X4Rgba32 block, EncodingQuality quality)
{
Bc4Block output = new Bc4Block();
byte[] colors = new byte[16];
var pixels = block.AsSpan;
for (int i = 0; i < 16; i++)
{
if (luminanceAsRed)
{
colors[i] = (byte)(new ColorYCbCr(pixels[i]).y * 255);
}
else
{
colors[i] = pixels[i].R;
}
}
switch (quality)
{
case EncodingQuality.Fast:
return(FindRedValues(output, colors, 3));
case EncodingQuality.Balanced:
return(FindRedValues(output, colors, 4));
case EncodingQuality.BestQuality:
return(FindRedValues(output, colors, 8));
default:
throw new ArgumentOutOfRangeException(nameof(quality), quality, null);
}
}