mirror of https://github.com/nothings/stb
Andreas Haferburg
parent
72646ac4ae
commit
c70479c47b
72
stb_dxt.h
72
stb_dxt.h
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@ -21,10 +21,10 @@
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// v1.01 - (stb) fix bug converting to RGB that messed up quality, thanks ryg & cbloom
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// v1.00 - (stb) first release
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//
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// contributors:
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// contributors:
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// Kevin Schmidt (#defines for "freestanding" compilation)
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// github:ppiastucki (BC4 support)
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//
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//
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// LICENSE
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//
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// See end of file for license information.
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@ -66,7 +66,7 @@ STBDDEF void stb_compress_bc5_block(unsigned char *dest, const unsigned char *sr
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// STB_DXT_USE_ROUNDING_BIAS
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// use a rounding bias during color interpolation. this is closer to what "ideal"
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// interpolation would do but doesn't match the S3TC/DX10 spec. old versions (pre-1.03)
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// implicitly had this turned on.
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// implicitly had this turned on.
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//
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// in case you're targeting a specific type of hardware (e.g. console programmers):
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// NVidia and Intel GPUs (as of 2010) as well as DX9 ref use DXT decoders that are closer
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@ -157,7 +157,7 @@ static void stb__PrepareOptTable(unsigned char *Table,const unsigned char *expan
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int mine = expand[mn];
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int maxe = expand[mx];
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int err = STBD_ABS(stb__Lerp13(maxe, mine) - i);
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// DX10 spec says that interpolation must be within 3% of "correct" result,
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// add this as error term. (normally we'd expect a random distribution of
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// +-1.5% error, but nowhere in the spec does it say that the error has to be
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@ -236,7 +236,7 @@ static unsigned int stb__MatchColorsBlock(unsigned char *block, unsigned char *c
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// relying on this 1d approximation isn't always optimal in terms of euclidean distance,
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// but it's very close and a lot faster.
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// http://cbloomrants.blogspot.com/2008/12/12-08-08-dxtc-summary.html
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c0Point = (stops[1] + stops[3]) >> 1;
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halfPoint = (stops[3] + stops[2]) >> 1;
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c3Point = (stops[2] + stops[0]) >> 1;
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@ -488,11 +488,11 @@ static int stb__RefineBlock(unsigned char *block, unsigned short *pmax16, unsign
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fg = frb * 63.0f / 31.0f;
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// solve.
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max16 = (unsigned short)(stb__sclamp((At1_r*yy - At2_r*xy)*frb+0.5f,0,31) << 11);
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max16 = (unsigned short)(stb__sclamp((At1_r*yy - At2_r*xy)*frb+0.5f,0,31) << 11);
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max16 |= (unsigned short)(stb__sclamp((At1_g*yy - At2_g*xy)*fg +0.5f,0,63) << 5);
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max16 |= (unsigned short)(stb__sclamp((At1_b*yy - At2_b*xy)*frb+0.5f,0,31) << 0);
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min16 = (unsigned short)(stb__sclamp((At2_r*xx - At1_r*xy)*frb+0.5f,0,31) << 11);
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min16 = (unsigned short)(stb__sclamp((At2_r*xx - At1_r*xy)*frb+0.5f,0,31) << 11);
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min16 |= (unsigned short)(stb__sclamp((At2_g*xx - At1_g*xy)*fg +0.5f,0,63) << 5);
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min16 |= (unsigned short)(stb__sclamp((At2_b*xx - At1_b*xy)*frb+0.5f,0,31) << 0);
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}
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@ -511,7 +511,7 @@ static void stb__CompressColorBlock(unsigned char *dest, unsigned char *block, i
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int refinecount;
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unsigned short max16, min16;
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unsigned char dblock[16*4],color[4*4];
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dither = mode & STB_DXT_DITHER;
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refinecount = (mode & STB_DXT_HIGHQUAL) ? 2 : 1;
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@ -541,7 +541,7 @@ static void stb__CompressColorBlock(unsigned char *dest, unsigned char *block, i
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// third step: refine (multiple times if requested)
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for (i=0;i<refinecount;i++) {
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unsigned int lastmask = mask;
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if (stb__RefineBlock(dither ? dblock : block,&max16,&min16,mask)) {
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if (max16 != min16) {
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stb__EvalColors(color,max16,min16);
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@ -551,7 +551,7 @@ static void stb__CompressColorBlock(unsigned char *dest, unsigned char *block, i
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break;
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}
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}
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if(mask == lastmask)
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break;
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}
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@ -605,7 +605,7 @@ static void stb__CompressAlphaBlock(unsigned char *dest,unsigned char *src, int
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bias = (dist < 8) ? (dist - 1) : (dist/2 + 2);
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bias -= mn * 7;
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bits = 0,mask=0;
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for (i=0;i<16;i++) {
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int a = src[i*stride]*7 + bias;
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int ind,t;
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@ -614,7 +614,7 @@ static void stb__CompressAlphaBlock(unsigned char *dest,unsigned char *src, int
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t = (a >= dist4) ? -1 : 0; ind = t & 4; a -= dist4 & t;
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t = (a >= dist2) ? -1 : 0; ind += t & 2; a -= dist2 & t;
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ind += (a >= dist);
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// turn linear scale into DXT index (0/1 are extremal pts)
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ind = -ind & 7;
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ind ^= (2 > ind);
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@ -691,38 +691,38 @@ This software is available under 2 licenses -- choose whichever you prefer.
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------------------------------------------------------------------------------
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ALTERNATIVE A - MIT License
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Copyright (c) 2017 Sean Barrett
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Permission is hereby granted, free of charge, to any person obtaining a copy of
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this software and associated documentation files (the "Software"), to deal in
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the Software without restriction, including without limitation the rights to
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use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
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of the Software, and to permit persons to whom the Software is furnished to do
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Permission is hereby granted, free of charge, to any person obtaining a copy of
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this software and associated documentation files (the "Software"), to deal in
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the Software without restriction, including without limitation the rights to
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use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
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of the Software, and to permit persons to whom the Software is furnished to do
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so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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------------------------------------------------------------------------------
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ALTERNATIVE B - Public Domain (www.unlicense.org)
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This is free and unencumbered software released into the public domain.
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Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
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software, either in source code form or as a compiled binary, for any purpose,
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Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
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software, either in source code form or as a compiled binary, for any purpose,
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commercial or non-commercial, and by any means.
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In jurisdictions that recognize copyright laws, the author or authors of this
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software dedicate any and all copyright interest in the software to the public
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domain. We make this dedication for the benefit of the public at large and to
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the detriment of our heirs and successors. We intend this dedication to be an
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overt act of relinquishment in perpetuity of all present and future rights to
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In jurisdictions that recognize copyright laws, the author or authors of this
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software dedicate any and all copyright interest in the software to the public
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domain. We make this dedication for the benefit of the public at large and to
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the detriment of our heirs and successors. We intend this dedication to be an
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overt act of relinquishment in perpetuity of all present and future rights to
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this software under copyright law.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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------------------------------------------------------------------------------
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*/
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