public byte[] Compress(Color[] colors)
{
var colorSpace = new ColorSpace(colors);
var colorTable = Helpers.CreateFor1BitAlpha(colorSpace.MinColor, colorSpace.MaxColor);
var block = new BC1BlockData
{
Color0 = colorTable[0],
Color1 = colorTable[1]
};
for (int i = 0; i < colors.Length; ++i)
{
var color32 = colors[i];
// If color has alpha, use a specific index
// to identify the color when decompressed
block.ColorIndexes[i] = Helpers.GetIndexOfClosestColor(colorTable, Helpers.To16Bit(color32));
}
var b = block.ToBytes();
return(b);
}
/// <summary>
/// Instantiates a <see cref="BC1BlockData"/> from compressed BC1 block data.
/// </summary>
public static BC1BlockData FromBytes(byte[] bytes)
{
var color0Low = bytes[0];
var color0High = bytes[1];
var color1Low = bytes[2];
var color1Hight = bytes[3];
var indexes = new byte[4];
indexes[0] = bytes[4];
indexes[1] = bytes[5];
indexes[2] = bytes[6];
indexes[3] = bytes[7];
var block = new BC1BlockData
{
Color0 = Helpers.FromValue((ushort)((color0High << 8) | color0Low)),
Color1 = Helpers.FromValue((ushort)((color1Hight << 8) | color1Low))
};
for (int p = 0, row = 0; p < Constants.TexelCount; p += Constants.BlockDimension, ++row)
{
block.ColorIndexes[p] = indexes[row] & 0x03;
block.ColorIndexes[p + 1] = (indexes[row] >> 2) & 0x03;
block.ColorIndexes[p + 2] = (indexes[row] >> 4) & 0x03;
block.ColorIndexes[p + 3] = (indexes[row] >> 6) & 0x03;
}
return(block);
}
public Color[] Decompress(byte[] blockData)
{
var block = BC1BlockData.FromBytes(blockData);
var colorTable = Helpers.CreateFor1BitAlpha(block.Color0, block.Color1);
var colors = new Color[Constants.TexelCount];
for (int i = 0; i < colors.Length; ++i)
{
int index = block.ColorIndexes[i];
int alpha = 255;
var color16 = colorTable[index];
var color32 = Color.FromArgb(alpha, Helpers.To32Bit(color16));
colors[i] = color32;
}
return(colors);
}
