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by rasz
1322 days ago
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>nerfing perfectly well-working hardware S3TC, texture compression on mobile killed after S3 lawsuit https://www.prnewswire.com/news-releases/itc-judge-rules-tha... The irony? Apple invented this very technique, encoding 4 colors using 2 values. Hoffert work at Apple Advanced Technology Group and consequent patents from 1990 (US5046119A) for Apple Video 'road pizza' codec, except S3 their patent added "for texture compression" at the end. The patent is about dividing colorspace between two points and is directly copied from mode 0xC0 of the original Apple Video codec. ~10 years later S3 sues and wins because Apple is somehow incompetent at proving prior art. https://wiki.multimedia.cx/index.php/Apple_RPZA#0xC0:_4_Colo... color0 = colorB
color1 = (11 * colorA + 21 * colorB) / 32
color2 = (21 * colorA + 11 * colorB) / 32
color3 = colorA
https://www.khronos.org/opengl/wiki/S3_Texture_Compression DXT2/DXT3: 0 color0
1 color1
2 (2*color0 + color1) / 3
3 (color0 + 2*color1) / 3
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