diff options
Diffstat (limited to 'src/utils/SkTextureCompressor_LATC.cpp')
| -rw-r--r-- | src/utils/SkTextureCompressor_LATC.cpp | 106 |
1 files changed, 38 insertions, 68 deletions
diff --git a/src/utils/SkTextureCompressor_LATC.cpp b/src/utils/SkTextureCompressor_LATC.cpp index 5db0fc6c04..9d42b4f71d 100644 --- a/src/utils/SkTextureCompressor_LATC.cpp +++ b/src/utils/SkTextureCompressor_LATC.cpp @@ -17,46 +17,6 @@ //////////////////////////////////////////////////////////////////////////////// -// Generates an LATC palette. LATC constructs -// a palette of eight colors from LUM0 and LUM1 using the algorithm: -// -// LUM0, if lum0 > lum1 and code(x,y) == 0 -// LUM1, if lum0 > lum1 and code(x,y) == 1 -// (6*LUM0+ LUM1)/7, if lum0 > lum1 and code(x,y) == 2 -// (5*LUM0+2*LUM1)/7, if lum0 > lum1 and code(x,y) == 3 -// (4*LUM0+3*LUM1)/7, if lum0 > lum1 and code(x,y) == 4 -// (3*LUM0+4*LUM1)/7, if lum0 > lum1 and code(x,y) == 5 -// (2*LUM0+5*LUM1)/7, if lum0 > lum1 and code(x,y) == 6 -// ( LUM0+6*LUM1)/7, if lum0 > lum1 and code(x,y) == 7 -// -// LUM0, if lum0 <= lum1 and code(x,y) == 0 -// LUM1, if lum0 <= lum1 and code(x,y) == 1 -// (4*LUM0+ LUM1)/5, if lum0 <= lum1 and code(x,y) == 2 -// (3*LUM0+2*LUM1)/5, if lum0 <= lum1 and code(x,y) == 3 -// (2*LUM0+3*LUM1)/5, if lum0 <= lum1 and code(x,y) == 4 -// ( LUM0+4*LUM1)/5, if lum0 <= lum1 and code(x,y) == 5 -// 0, if lum0 <= lum1 and code(x,y) == 6 -// 255, if lum0 <= lum1 and code(x,y) == 7 - -static const int kLATCPaletteSize = 8; -static void generate_latc_palette(uint8_t palette[], uint8_t lum0, uint8_t lum1) { - palette[0] = lum0; - palette[1] = lum1; - if (lum0 > lum1) { - for (int i = 1; i < 7; i++) { - palette[i+1] = ((7-i)*lum0 + i*lum1) / 7; - } - } else { - for (int i = 1; i < 5; i++) { - palette[i+1] = ((5-i)*lum0 + i*lum1) / 5; - } - palette[6] = 0; - palette[7] = 255; - } -} - -//////////////////////////////////////////////////////////////////////////////// - #if COMPRESS_LATC_SLOW //////////////////////////////////////////////////////////////////////////////// @@ -119,9 +79,47 @@ static bool compress_4x4_a8_to_64bit(uint8_t* dst, const uint8_t* src, //////////////////////////////////////////////////////////////////////////////// // LATC compressed texels down into square 4x4 blocks +static const int kLATCPaletteSize = 8; static const int kLATCBlockSize = 4; static const int kLATCPixelsPerBlock = kLATCBlockSize * kLATCBlockSize; +// Generates an LATC palette. LATC constructs +// a palette of eight colors from LUM0 and LUM1 using the algorithm: +// +// LUM0, if lum0 > lum1 and code(x,y) == 0 +// LUM1, if lum0 > lum1 and code(x,y) == 1 +// (6*LUM0+ LUM1)/7, if lum0 > lum1 and code(x,y) == 2 +// (5*LUM0+2*LUM1)/7, if lum0 > lum1 and code(x,y) == 3 +// (4*LUM0+3*LUM1)/7, if lum0 > lum1 and code(x,y) == 4 +// (3*LUM0+4*LUM1)/7, if lum0 > lum1 and code(x,y) == 5 +// (2*LUM0+5*LUM1)/7, if lum0 > lum1 and code(x,y) == 6 +// ( LUM0+6*LUM1)/7, if lum0 > lum1 and code(x,y) == 7 +// +// LUM0, if lum0 <= lum1 and code(x,y) == 0 +// LUM1, if lum0 <= lum1 and code(x,y) == 1 +// (4*LUM0+ LUM1)/5, if lum0 <= lum1 and code(x,y) == 2 +// (3*LUM0+2*LUM1)/5, if lum0 <= lum1 and code(x,y) == 3 +// (2*LUM0+3*LUM1)/5, if lum0 <= lum1 and code(x,y) == 4 +// ( LUM0+4*LUM1)/5, if lum0 <= lum1 and code(x,y) == 5 +// 0, if lum0 <= lum1 and code(x,y) == 6 +// 255, if lum0 <= lum1 and code(x,y) == 7 + +static void generate_latc_palette(uint8_t palette[], uint8_t lum0, uint8_t lum1) { + palette[0] = lum0; + palette[1] = lum1; + if (lum0 > lum1) { + for (int i = 1; i < 7; i++) { + palette[i+1] = ((7-i)*lum0 + i*lum1) / 7; + } + } else { + for (int i = 1; i < 5; i++) { + palette[i+1] = ((5-i)*lum0 + i*lum1) / 5; + } + palette[6] = 0; + palette[7] = 255; + } +} + // Compress a block by using the bounding box of the pixels. It is assumed that // there are no extremal pixels in this block otherwise we would have used // compressBlockBBIgnoreExtremal. @@ -395,24 +393,6 @@ void CompressA8LATCBlockVertical(uint8_t* dst, const uint8_t block[]) { #endif // COMPRESS_LATC_FAST -void decompress_latc_block(uint8_t* dst, int dstRowBytes, const uint8_t* src) { - uint64_t block = SkEndian_SwapLE64(*(reinterpret_cast<const uint64_t *>(src))); - uint8_t lum0 = block & 0xFF; - uint8_t lum1 = (block >> 8) & 0xFF; - - uint8_t palette[kLATCPaletteSize]; - generate_latc_palette(palette, lum0, lum1); - - block >>= 16; - for (int j = 0; j < 4; ++j) { - for (int i = 0; i < 4; ++i) { - dst[i] = palette[block & 0x7]; - block >>= 3; - } - dst += dstRowBytes; - } -} - //////////////////////////////////////////////////////////////////////////////// namespace SkTextureCompressor { @@ -438,14 +418,4 @@ SkBlitter* CreateLATCBlitter(int width, int height, void* outputBuffer) { #endif } -void DecompressLATC(uint8_t* dst, int dstRowBytes, const uint8_t* src, int width, int height) { - for (int j = 0; j < height; j += 4) { - for (int i = 0; i < width; i += 4) { - decompress_latc_block(dst + i, dstRowBytes, src); - src += 8; - } - dst += 4 * dstRowBytes; - } -} - } // SkTextureCompressor |