public static Color ReadColor(BinaryReader BR, int BitDepth)
{
switch (BitDepth)
{
case 16:
return(Graphic.DecodeRGB565(BR.ReadUInt16()));
case 32:
case 24:
{
int B = BR.ReadByte();
int G = BR.ReadByte();
int R = BR.ReadByte();
int A = 255;
if (BitDepth == 32)
{
byte SemiAlpha = BR.ReadByte();
if (SemiAlpha < 0x80)
{
A = 2 * SemiAlpha;
}
}
return(Color.FromArgb(A, R, G, B));
}
case 8:
{
int GrayScale = BR.ReadByte();
return(Color.FromArgb(GrayScale, GrayScale, GrayScale));
}
default:
return(Color.HotPink);
}
}
private Color[] ReadTexelBlock(BinaryReader BR, string FourCC)
{
ulong AlphaBlock = 0;
if (FourCC == "DXT2" || FourCC == "DXT3" || FourCC == "DXT4" || FourCC == "DXT5")
{
AlphaBlock = BR.ReadUInt64();
}
else if (FourCC != "DXT1")
{
return(null);
}
ushort C0 = BR.ReadUInt16();
ushort C1 = BR.ReadUInt16();
Color[] Colors = new Color[4];
Colors[0] = Graphic.DecodeRGB565(C0);
Colors[1] = Graphic.DecodeRGB565(C1);
if (C0 > C1 || FourCC != "DXT1")
{
// opaque, 4-color
Colors[2] = Color.FromArgb((2 * Colors[0].R + Colors[1].R + 1) / 3, (2 * Colors[0].G + Colors[1].G + 1) / 3,
(2 * Colors[0].B + Colors[1].B + 1) / 3);
Colors[3] = Color.FromArgb((2 * Colors[1].R + Colors[0].R + 1) / 3, (2 * Colors[1].G + Colors[0].G + 1) / 3,
(2 * Colors[1].B + Colors[0].B + 1) / 3);
}
else
{
// 1-bit alpha, 3-color
Colors[2] = Color.FromArgb((Colors[0].R + Colors[1].R) / 2, (Colors[0].G + Colors[1].G) / 2,
(Colors[0].B + Colors[1].B) / 2);
Colors[3] = Color.Transparent;
}
uint CompressedColor = BR.ReadUInt32();
Color[] DecodedColors = new Color[16];
for (int i = 0; i < 16; ++i)
{
if (FourCC == "DXT2" || FourCC == "DXT3" || FourCC == "DXT4" || FourCC == "DXT5")
{
int A = 255;
#if EnableTransparency
if (FourCC == "DXT2" || FourCC == "DXT3")
{
// Seems to be 8 maximum; so treat 8 as 255 and all other values as 3-bit alpha
A = (int)((AlphaBlock >> (4 * i)) & 0xf);
if (A >= 8)
{
A = 255;
}
else
{
A <<= 5;
}
}
else
{
// Interpolated alpha
int[] Alphas = new int[8];
Alphas[0] = (byte)((AlphaBlock >> 0) & 0xff);
Alphas[1] = (byte)((AlphaBlock >> 8) & 0xff);
if (Alphas[0] > Alphas[1])
{
Alphas[2] = (Alphas[0] * 6 + Alphas[1] * 1 + 3) / 7;
Alphas[3] = (Alphas[0] * 5 + Alphas[1] * 2 + 3) / 7;
Alphas[4] = (Alphas[0] * 4 + Alphas[1] * 3 + 3) / 7;
Alphas[5] = (Alphas[0] * 3 + Alphas[1] * 4 + 3) / 7;
Alphas[6] = (Alphas[0] * 2 + Alphas[1] * 5 + 3) / 7;
Alphas[7] = (Alphas[0] * 1 + Alphas[1] * 6 + 3) / 7;
}
else
{
Alphas[2] = (Alphas[0] * 4 + Alphas[1] * 1 + 2) / 5;
Alphas[3] = (Alphas[0] * 3 + Alphas[1] * 2 + 2) / 5;
Alphas[4] = (Alphas[0] * 2 + Alphas[1] * 3 + 2) / 5;
Alphas[5] = (Alphas[0] * 1 + Alphas[1] * 4 + 2) / 5;
Alphas[6] = 0;
Alphas[7] = 255;
}
ulong AlphaMatrix = (AlphaBlock >> 16) & 0xffffffffffffL;
A = Alphas[(AlphaMatrix >> (3 * i)) & 0x7];
}
#endif
DecodedColors[i] = Color.FromArgb(A, Colors[CompressedColor & 0x3]);
}
else
{
DecodedColors[i] = Colors[CompressedColor & 0x3];
}
CompressedColor >>= 2;
}
return(DecodedColors);
}