static int pvrtcDecompress(byte[] pCompressedData, ref Pixel32[] pDecompressedData, uint ui32Width, uint ui32Height, byte ui8Bpp)
{
uint ui32WordWidth = 4;
uint ui32WordHeight = 4;
if (ui8Bpp == 2)
{
ui32WordWidth = 8;
}
uint[] pWordMembers = new uint[pCompressedData.Length / 4];
for (int i = 0; i < pCompressedData.Length; i += 4)
{
pWordMembers[i / 4] = BitConverter.ToUInt32(pCompressedData, i);
}
int i32NumXWords = (int)(ui32Width / ui32WordWidth);
int i32NumYWords = (int)(ui32Height / ui32WordHeight);
PVRTCWordIndices indices;
Pixel32[] pPixels = new Pixel32[ui32WordWidth * ui32WordHeight];
for (int wordY = -1; wordY < i32NumYWords - 1; wordY++)
{
for (int wordX = -1; wordX < i32NumXWords - 1; wordX++)
{
indices = new PVRTCWordIndices(
(int)wrapWordIndex((uint)i32NumXWords, wordX),
(int)wrapWordIndex((uint)i32NumYWords, wordY),
(int)wrapWordIndex((uint)i32NumXWords, wordX + 1),
(int)wrapWordIndex((uint)i32NumYWords, wordY),
(int)wrapWordIndex((uint)i32NumXWords, wordX),
(int)wrapWordIndex((uint)i32NumYWords, wordY + 1),
(int)wrapWordIndex((uint)i32NumXWords, wordX + 1),
(int)wrapWordIndex((uint)i32NumYWords, wordY + 1));
uint[] WordOffsets = new uint[4]
{
TwiddleUV((uint)i32NumXWords, (uint)i32NumYWords, (uint)indices.P[0], (uint)indices.P[1]) * 2,
TwiddleUV((uint)i32NumXWords, (uint)i32NumYWords, (uint)indices.Q[0], (uint)indices.Q[1]) * 2,
TwiddleUV((uint)i32NumXWords, (uint)i32NumYWords, (uint)indices.R[0], (uint)indices.R[1]) * 2,
TwiddleUV((uint)i32NumXWords, (uint)i32NumYWords, (uint)indices.S[0], (uint)indices.S[1]) * 2,
};
PVRTCWord P, Q, R, S;
P.u32ColorData = pWordMembers[WordOffsets[0] + 1];
P.u32ModulationData = pWordMembers[WordOffsets[0]];
Q.u32ColorData = pWordMembers[WordOffsets[1] + 1];
Q.u32ModulationData = pWordMembers[WordOffsets[1]];
R.u32ColorData = pWordMembers[WordOffsets[2] + 1];
R.u32ModulationData = pWordMembers[WordOffsets[2]];
S.u32ColorData = pWordMembers[WordOffsets[3] + 1];
S.u32ModulationData = pWordMembers[WordOffsets[3]];
pvrtcGetDecompressedPixels(P, Q, R, S, ref pPixels, ui8Bpp);
mapDecompressedData(ref pDecompressedData, (int)ui32Width, pPixels, indices, ui8Bpp);
}
}
return((int)(ui32Width * ui32Height / (uint)(ui32WordWidth / 2)));
}
static void mapDecompressedData(ref Pixel32[] pOutput, int width, Pixel32[] pWord, PVRTCWordIndices words, byte ui8Bpp)
{
uint ui32WordWidth = 4;
uint ui32WordHeight = 4;
if (ui8Bpp == 2)
{
ui32WordWidth = 8;
}
for (uint y = 0; y < ui32WordHeight / 2; y++)
{
for (uint x = 0; x < ui32WordWidth / 2; x++)
{
pOutput[(((words.P[1] * ui32WordHeight) + y + ui32WordHeight / 2)
* width + words.P[0] * ui32WordWidth + x + ui32WordWidth / 2)] = pWord[y * ui32WordWidth + x];
pOutput[(((words.Q[1] * ui32WordHeight) + y + ui32WordHeight / 2)
* width + words.Q[0] * ui32WordWidth + x)] = pWord[y * ui32WordWidth + x + ui32WordWidth / 2];
pOutput[(((words.R[1] * ui32WordHeight) + y)
* width + words.R[0] * ui32WordWidth + x + ui32WordWidth / 2)] = pWord[(y + ui32WordHeight / 2) * ui32WordWidth + x];
pOutput[(((words.S[1] * ui32WordHeight) + y)
* width + words.S[0] * ui32WordWidth + x)] = pWord[(y + ui32WordHeight / 2) * ui32WordWidth + x + ui32WordWidth / 2];
}
}
}
