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Merge pull request #60 from attilaz/etc2a_decode

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added etc2a decoder
This commit is contained in:
Бранимир Караџић
2021-08-03 07:48:24 -07:00
committed by GitHub
parent 82738cde49 ceea976049
commit 39c0a7885d
1 changed files with 70 additions and 2 deletions
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72
src/image.cpp
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@@ -2934,6 +2934,52 @@ namespace bimg
}
}
static const int8_t s_etc2aMod[16][8] =
{
{ -3, -6, -9, -15, 2, 5, 8, 14 },
{ -3, -7, -10, -13, 2, 6, 9, 12 },
{ -2, -5, -8, -13, 1, 4, 7, 12 },
{ -2, -4, -6, -13, 1, 3, 5, 12 },
{ -3, -6, -8, -12, 2, 5, 7, 11 },
{ -3, -7, -9, -11, 2, 6, 8, 10 },
{ -4, -7, -8, -11, 3, 6, 7, 10 },
{ -3, -5, -8, -11, 2, 4, 7, 10 },
{ -2, -6, -8, -10, 1, 5, 7, 9 },
{ -2, -5, -8, -10, 1, 4, 7, 9 },
{ -2, -4, -8, -10, 1, 3, 7, 9 },
{ -2, -5, -7, -10, 1, 4, 6, 9 },
{ -3, -4, -7, -10, 2, 3, 6, 9 },
{ -1, -2, -3, -10, 0, 1, 2, 9 },
{ -4, -6, -8, -9, 3, 5, 7, 8 },
{ -3, -5, -7, -9, 2, 4, 6, 8 }
};
void decodeBlockEtc2Alpha(uint8_t _dst[16 * 4], const uint8_t _src[8])
{
if (!BX_ENABLED(BIMG_DECODE_ETC2))
{
return;
}
const int32_t bc = _src[0];
const int8_t *modTable = s_etc2aMod[_src[1] & 0x0f];
const int32_t mult = (_src[1] & 0xf0) >> 4;
const uint64_t indices = ((uint64_t)_src[2] << 40)
| ((uint64_t)_src[3] << 32)
| ((uint64_t)_src[4] << 24)
| ((uint64_t)_src[5] << 16)
| ((uint64_t)_src[6] << 8)
| _src[7];
for (int ii = 0; ii < 16; ii++) {
const uint32_t idx = (ii & 0xc) | ((ii & 0x3) << 4);
const int32_t mod = modTable[(indices >> (45 - ii * 3)) & 0x7];
_dst[idx + 3] = uint8_satadd(bc, mod*mult);
}
}
static const uint8_t s_pvrtcFactors[16][4] =
{
{ 4, 4, 4, 4 },
@@ -4544,8 +4590,30 @@ namespace bimg
break;
case TextureFormat::ETC2A:
BX_WARN(false, "ETC2A decoder is not implemented.");
imageCheckerboard(_dst, _width, _height, 16, UINT32_C(0xff000000), UINT32_C(0xff00ff00) );
if (BX_ENABLED(BIMG_DECODE_ETC2))
{
for (uint32_t yy = 0; yy < height; ++yy)
{
for (uint32_t xx = 0; xx < width; ++xx)
{
decodeBlockEtc12(temp, src + 8);
decodeBlockEtc2Alpha(temp, src);
src += 16;
uint8_t* block = &dst[yy*_dstPitch * 4 + xx * 16];
bx::memCopy(&block[0 * _dstPitch], &temp[0], 16);
bx::memCopy(&block[1 * _dstPitch], &temp[16], 16);
bx::memCopy(&block[2 * _dstPitch], &temp[32], 16);
bx::memCopy(&block[3 * _dstPitch], &temp[48], 16);
}
}
}
else
{
BX_WARN(false, "ETC2 decoder is disabled (BIMG_DECODE_ETC2).");
imageCheckerboard(_dst, _width, _height, 16, UINT32_C(0xff000000), UINT32_C(0xff00ff00));
}
break;
case TextureFormat::ETC2A1: