public void GetPalette(Rgb565[] palette, int index = 0)
{
if (palette == null)
{
throw new ArgumentNullException("palette");
}
if (index < 0)
{
throw new ArgumentOutOfRangeException("index");
}
if (palette.Length - index < 4)
{
throw new ArgumentOutOfRangeException("index");
}
var c0 = Rgb0;
var c1 = Rgb1;
palette[index + 0] = c0;
palette[index + 1] = c1;
if (HasTransparentValues)
{
var interp = new Rgb565();
interp.R = (c0.R + c1.R) / 2;
interp.G = (c0.G + c1.G) / 2;
interp.B = (c0.B + c1.B) / 2;
palette[index + 2] = interp;
palette[index + 3] = new Rgb565(0);
}
else
{
var interp = new Rgb565();
interp.R = (c0.R * 2 + c1.R) / 3;
interp.G = (c0.G * 2 + c1.G) / 3;
interp.B = (c0.B * 2 + c1.B) / 3;
palette[index + 2] = interp;
interp.R = (c0.R + c1.R * 2) / 3;
interp.G = (c0.G + c1.G * 2) / 3;
interp.B = (c0.B + c1.B * 2) / 3;
palette[index + 3] = interp;
}
}
public BC1Block Encode()
{
BC1Block ret;
if (alphaMask == 0xFFFF)
{
ret.PackedValue = BC1Block.TransparentValue;
return(ret);
}
QuantizeValues();
RgbF32 r0, r1;
SpanValues(out r0, out r1);
//quantize the endpoints
bool weightValues = !UseUniformWeighting;
if (weightValues)
{
r0.R *= RInvWeight;
r0.G *= GInvWeight;
r0.B *= BInvWeight;
r1.R *= RInvWeight;
r1.G *= GInvWeight;
r1.B *= BInvWeight;
}
var pr0 = Rgb565.Pack(r0);
var pr1 = Rgb565.Pack(r1);
if (alphaMask == 0 && pr0.PackedValue == pr1.PackedValue)
{
return(new BC1Block(pr0, pr1));
}
pr0.Unpack(out r0);
pr1.Unpack(out r1);
if (weightValues)
{
r0.R *= RWeight;
r0.G *= GWeight;
r0.B *= BWeight;
r1.R *= RWeight;
r1.G *= GWeight;
r1.B *= BWeight;
}
//interp out the steps
RgbF32 s0;
if ((alphaMask != 0) == (pr0.PackedValue <= pr1.PackedValue))
{
ret = new BC1Block(pr0, pr1);
interpValues[0] = s0 = r0;
interpValues[1] = r1;
}
else
{
ret = new BC1Block(pr1, pr0);
interpValues[0] = s0 = r1;
interpValues[1] = r0;
}
uint[] pSteps;
if (alphaMask != 0)
{
pSteps = pSteps3;
RgbF32.Lerp(out interpValues[2], interpValues[0], interpValues[1], 0.5F);
}
else
{
pSteps = pSteps4;
RgbF32.Lerp(out interpValues[2], interpValues[0], interpValues[1], 1.0F / 3.0F);
RgbF32.Lerp(out interpValues[3], interpValues[0], interpValues[1], 2.0F / 3.0F);
}
//find the best values
RgbF32 dir;
dir.R = interpValues[1].R - s0.R;
dir.G = interpValues[1].G - s0.G;
dir.B = interpValues[1].B - s0.B;
float fSteps = alphaMask != 0 ? 2 : 3;
float fScale = (pr0.PackedValue != pr1.PackedValue) ?
(fSteps / (dir.R * dir.R + dir.G * dir.G + dir.B * dir.B)) : 0.0F;
dir.R *= fScale;
dir.G *= fScale;
dir.B *= fScale;
bool dither = DitherRgb;
if (dither)
{
if (error == null)
{
error = new RgbF32[16];
}
else
{
Array.Clear(error, 0, 16);
}
}
for (int i = 0; i < values.Length; i++)
{
if ((alphaMask & (1 << i)) != 0)
{
ret.PackedValue |= 3U << (32 + i * 2);
}
else
{
var cl = values[i];
if (weightValues)
{
cl.R *= RWeight;
cl.G *= GWeight;
cl.B *= BWeight;
}
if (dither)
{
var e = error[i];
cl.R += e.R;
cl.G += e.G;
cl.B += e.B;
}
float fDot =
(cl.R - s0.R) * dir.R +
(cl.G - s0.G) * dir.G +
(cl.B - s0.B) * dir.B;
uint iStep;
if (fDot <= 0)
{
iStep = 0;
}
else if (fDot >= fSteps)
{
iStep = 1;
}
else
{
iStep = pSteps[(int)(fDot + 0.5F)];
}
ret.PackedValue |= (ulong)iStep << (32 + i * 2);
if (dither)
{
RgbF32 e, d, interp = interpValues[iStep];
d.R = cl.R - interp.R;
d.G = cl.G - interp.G;
d.B = cl.B - interp.B;
if ((i & 3) != 3)
{
e = error[i + 1];
e.R += d.R * (7.0F / 16.0F);
e.G += d.G * (7.0F / 16.0F);
e.B += d.B * (7.0F / 16.0F);
error[i + 1] = e;
}
if (i < 12)
{
if ((i & 3) != 0)
{
e = error[i + 3];
e.R += d.R * (3.0F / 16.0F);
e.G += d.G * (3.0F / 16.0F);
e.B += d.B * (3.0F / 16.0F);
error[i + 3] = e;
}
e = error[i + 4];
e.R += d.R * (5.0F / 16.0F);
e.G += d.G * (5.0F / 16.0F);
e.B += d.B * (5.0F / 16.0F);
error[i + 4] = e;
if (3 != (i & 3))
{
e = error[i + 5];
e.R += d.R * (1.0F / 16.0F);
e.G += d.G * (1.0F / 16.0F);
e.B += d.B * (1.0F / 16.0F);
error[i + 5] = e;
}
}
}
}
}
return(ret);
}
public BC1Block(Rgb565 r0, Rgb565 r1)
{
PackedValue = ((ulong)r1.PackedValue << 16) | r0.PackedValue;
}