public static void Decompress(UInt32 width, UInt32 height, byte[] blockStorage, byte[] image)
{
UInt32 blockCountX = (width + 3) / 4;
UInt32 blockCountY = (height + 3) / 4;
UInt32 blockWidth = (width < 4) ? width : 4;
UInt32 blockHeight = (height < 4) ? height : 4;
UBytePtr blockStoragePtr = new UBytePtr(blockStorage);
for (UInt32 j = 0; j < blockCountY; j++)
{
for (UInt32 i = 0; i < blockCountX; i++)
{
DecompressBlockDXT1(i * 4, j * 4, width, blockStoragePtr + (i * 8), new UInt32Ptr(image));
}
blockStoragePtr += (blockCountX * 8);
}
}
public static void DecompressBlockDXT1(UInt32 x, UInt32 y, UInt32 width, UBytePtr blockStorage, UInt32Ptr image)
{
UInt16 color0 = blockStorage.asUInt16();
UInt16 color1 = (blockStorage + 2).asUInt16();
UInt32 temp;
temp = (UInt32)((color0 >> 11) * 255 + 16);
byte r0 = (byte)((temp / 32 + temp) / 32);
temp = (UInt32)(((color0 & 0x07E0) >> 5) * 255 + 32);
byte g0 = (byte)((temp / 64 + temp) / 64);
temp = (UInt32)((color0 & 0x001F) * 255 + 16);
byte b0 = (byte)((temp / 32 + temp) / 32);
temp = (UInt32)((color1 >> 11) * 255 + 16);
byte r1 = (byte)((temp / 32 + temp) / 32);
temp = (UInt32)(((color1 & 0x07E0) >> 5) * 255 + 32);
byte g1 = (byte)((temp / 64 + temp) / 64);
temp = (UInt32)((color1 & 0x001F) * 255 + 16);
byte b1 = (byte)((temp / 32 + temp) / 32);
UInt32 code = (blockStorage + 4).asUInt32();
for (int j = 0; j < 4; j++)
{
for (int i = 0; i < 4; i++)
{
UInt32 finalColor = 0;
byte positionCode = (byte)((code >> 2 * (4 * j + i)) & 0x03);
if (color0 > color1)
{
switch (positionCode)
{
case 0:
finalColor = PackRGBA(r0, g0, b0, 255);
break;
case 1:
finalColor = PackRGBA(r1, g1, b1, 255);
break;
case 2:
finalColor = PackRGBA((byte)((2 * r0 + r1) / 3), (byte)((2 * g0 + g1) / 3), (byte)((2 * b0 + b1) / 3), 255);
break;
case 3:
finalColor = PackRGBA((byte)((r0 + 2 * r1) / 3), (byte)((g0 + 2 * g1) / 3), (byte)((b0 + 2 * b1) / 3), 255);
break;
}
}
else
{
switch (positionCode)
{
case 0:
finalColor = PackRGBA(r0, g0, b0, 255);
break;
case 1:
finalColor = PackRGBA(r1, g1, b1, 255);
break;
case 2:
finalColor = PackRGBA((byte)((r0 + r1) / 2), (byte)((g0 + g1) / 2), (byte)((b0 + b1) / 2), 255);
break;
case 3:
finalColor = PackRGBA(0, 0, 0, 255);
break;
}
}
if (x + i < width)
{
image[(UInt32)((y + j) * width + (x + i))] = finalColor;
}
}
}
}
protected static void DecompressBlockDXT5(UInt32 x, UInt32 y, UInt32 width, UBytePtr blockStorage, UInt32Ptr image)
{
byte alpha0 = blockStorage[0];
byte alpha1 = blockStorage[1];
UBytePtr bits = blockStorage + 2;
UInt32 alphaCode1 = (UInt32)(bits[2] | (bits[3] << 8) | (bits[4] << 16) | (bits[5] << 24));
UInt16 alphaCode2 = (UInt16)(bits[0] | (bits[1] << 8));
UInt16 color0 = (blockStorage + 8).asUInt16();
UInt16 color1 = (blockStorage + 10).asUInt16();
UInt32 temp;
temp = (UInt32)((color0 >> 11) * 255 + 16);
byte r0 = (byte)((temp / 32 + temp) / 32);
temp = (UInt32)(((color0 & 0x07E0) >> 5) * 255 + 32);
byte g0 = (byte)((temp / 64 + temp) / 64);
temp = (UInt32)((color0 & 0x001F) * 255 + 16);
byte b0 = (byte)((temp / 32 + temp) / 32);
temp = (UInt32)((color1 >> 11) * 255 + 16);
byte r1 = (byte)((temp / 32 + temp) / 32);
temp = (UInt32)(((color1 & 0x07E0) >> 5) * 255 + 32);
byte g1 = (byte)((temp / 64 + temp) / 64);
temp = (UInt32)((color1 & 0x001F) * 255 + 16);
byte b1 = (byte)((temp / 32 + temp) / 32);
UInt32 code = (blockStorage + 12).asUInt32();
string s = "";
for (int j = 0; j < 4; j++)
{
for (int i = 0; i < 4; i++)
{
int alphaCodeIndex = 3 * (4 * j + i);
int alphaCode;
if (alphaCodeIndex <= 12)
{
alphaCode = (alphaCode2 >> alphaCodeIndex) & 0x07;
}
else if (alphaCodeIndex == 15)
{
alphaCode = (int)(((UInt32)alphaCode2 >> 15) | (((UInt64)alphaCode1 << 1) & 0x06));
}
else // alphaCodeIndex >= 18 && alphaCodeIndex <= 45
{
alphaCode = (int)((alphaCode1 >> (alphaCodeIndex - 16)) & 0x07);
}
byte finalAlpha;
if (alphaCode == 0)
{
finalAlpha = alpha0;
}
else if (alphaCode == 1)
{
finalAlpha = alpha1;
}
else
{
if (alpha0 > alpha1)
{
finalAlpha = (byte)(((8 - alphaCode) * alpha0 + (alphaCode - 1) * alpha1) / 7);
}
else
{
if (alphaCode == 6)
{
finalAlpha = 0;
}
else if (alphaCode == 7)
{
finalAlpha = 255;
}
else
{
finalAlpha = (byte)(((6 - alphaCode) * alpha0 + (alphaCode - 1) * alpha1) / 5);
}
}
}
s += string.Format("{0:X2}", finalAlpha);
byte colorCode = (byte)((code >> 2 * (4 * j + i)) & 0x03);
UInt32 finalColor = 0;
switch (colorCode)
{
case 0:
finalColor = PackRGBA(r0, g0, b0, finalAlpha);
break;
case 1:
finalColor = PackRGBA(r1, g1, b1, finalAlpha);
break;
case 2:
finalColor = PackRGBA((byte)((2 * r0 + r1) / 3), (byte)((2 * g0 + g1) / 3), (byte)((2 * b0 + b1) / 3), finalAlpha);
break;
case 3:
finalColor = PackRGBA((byte)((r0 + 2 * r1) / 3), (byte)((g0 + 2 * g1) / 3), (byte)((b0 + 2 * b1) / 3), finalAlpha);
break;
}
if (x + i < width)
{
image[(UInt32)((y + j) * width + (x + i))] = finalColor;
}
}
}
}
