private static Bc2Block TryColors(RawBlock4X4Rgba32 rawBlock, ColorRgb565 color0, ColorRgb565 color1, out float error, float rWeight = 0.3f, float gWeight = 0.6f, float bWeight = 0.1f)
{
Bc2Block output = new Bc2Block();
var pixels = rawBlock.AsSpan;
output.color0 = color0;
output.color1 = color1;
var c0 = color0.ToColorRgb24();
var c1 = color1.ToColorRgb24();
ReadOnlySpan <ColorRgb24> colors = stackalloc ColorRgb24[] {
c0,
c1,
c0 *(2.0 / 3.0) + c1 * (1.0 / 3.0),
c0 *(1.0 / 3.0) + c1 * (2.0 / 3.0)
};
error = 0;
for (int i = 0; i < 16; i++)
{
var color = pixels[i];
output.SetAlpha(i, color.A);
output[i] = ColorChooser.ChooseClosestColor4(colors, color, rWeight, gWeight, bWeight, out var e);
error += e;
}
return(output);
}
internal static Bc2Block EncodeBlock(RawBlock4X4Rgba32 rawBlock)
{
var pixels = rawBlock.AsSpan;
PcaVectors.Create(pixels, out var mean, out var principalAxis);
PcaVectors.GetMinMaxColor565(pixels, mean, principalAxis, out var min, out var max);
ColorRgb565 c0 = max;
ColorRgb565 c1 = min;
var output = TryColors(rawBlock, c0, c1, out var _);
return(output);
}
public static (ColorRgb565, ColorRgb565) Variate565(ColorRgb565 c0, ColorRgb565 c1, int i)
{
int idx = i % varPatternEp0R.Length;
var newEp0 = new ColorRgb565();
var newEp1 = new ColorRgb565();
newEp0.RawR = ByteHelper.ClampToByte(c0.RawR + varPatternEp0R[idx]);
newEp0.RawG = ByteHelper.ClampToByte(c0.RawG + varPatternEp0G[idx]);
newEp0.RawB = ByteHelper.ClampToByte(c0.RawB + varPatternEp0B[idx]);
newEp1.RawR = ByteHelper.ClampToByte(c1.RawR + varPatternEp1R[idx]);
newEp1.RawG = ByteHelper.ClampToByte(c1.RawG + varPatternEp1G[idx]);
newEp1.RawB = ByteHelper.ClampToByte(c1.RawB + varPatternEp1B[idx]);
return(newEp0, newEp1);
}
public void Rgb565Test()
{
ColorRgb565 color = new ColorRgb565(255, 255, 255);
Assert.Equal(255, color.R);
Assert.Equal(255, color.G);
Assert.Equal(255, color.B);
color.R = 0;
Assert.Equal(0, color.R);
Assert.Equal(255, color.G);
Assert.Equal(255, color.B);
color.G = 0;
Assert.Equal(0, color.R);
Assert.Equal(0, color.G);
Assert.Equal(255, color.B);
color.B = 0;
Assert.Equal(0, color.R);
Assert.Equal(0, color.G);
Assert.Equal(0, color.B);
color = new ColorRgb565(255, 255, 255);
color.B = 0;
Assert.Equal(255, color.R);
Assert.Equal(255, color.G);
Assert.Equal(0, color.B);
color.G = 0;
Assert.Equal(255, color.R);
Assert.Equal(0, color.G);
Assert.Equal(0, color.B);
color.R = 0;
Assert.Equal(0, color.R);
Assert.Equal(0, color.G);
Assert.Equal(0, color.B);
color = new ColorRgb565(127, 127, 127);
Assert.Equal(123, color.R);
Assert.Equal(125, color.G);
Assert.Equal(123, color.B);
}
private static Bc1Block TryColors(RawBlock4X4Rgba32 rawBlock, ColorRgb565 color0, ColorRgb565 color1, out float error, float rWeight = 0.3f, float gWeight = 0.6f, float bWeight = 0.1f)
{
Bc1Block output = new Bc1Block();
var pixels = rawBlock.AsSpan;
output.color0 = color0;
output.color1 = color1;
var c0 = color0.ToColorRgb24();
var c1 = color1.ToColorRgb24();
ReadOnlySpan <ColorRgb24> colors = output.HasAlphaOrBlack ?
stackalloc ColorRgb24[] {
c0,
c1,
c0 *(1.0 / 2.0) + c1 * (1.0 / 2.0),
new ColorRgb24(0, 0, 0)
} : stackalloc ColorRgb24[] {
internal static Bc3Block EncodeBlock(RawBlock4X4Rgba32 rawBlock)
{
var pixels = rawBlock.AsSpan;
PcaVectors.Create(pixels, out var mean, out var principalAxis);
PcaVectors.GetMinMaxColor565(pixels, mean, principalAxis, out var min, out var max);
ColorRgb565 c0 = max;
ColorRgb565 c1 = min;
if (c0.data <= c1.data)
{
var c = c0;
c0 = c1;
c1 = c;
}
var output = TryColors(rawBlock, c0, c1, out float _);
output = FindAlphaValues(output, rawBlock, 3);
return(output);
}
