Matt Turner <matts...@gmail.com> writes: > I was thinking one of the cool things we might be able to do a ETC2 -> > BC7 transcode on platforms without ETC2 hardware decompression. We > won't be able to do that without a good compressor.
That sounds like a fun project. It would be a shame to have to completely decompress it and then recompress it though. It looks like for ETC1 it wouldn't be too tricky to losslessly map it to mode 3 of BPTC. You could emulate the 2x4 or 4x2 selection by using either partition 0 or 13 resepectively and then you could pick 4 endpoint colours that match the range allowed by the difference values. The 'T' and 'H' modes of ETC2 would probably be a lot trickier to map though because the indices effectively let you pick between either of the two subsets on a per-texel basis. Maybe you could do a decompress-recompress per-block only if it is using one of these two modes. I'm not sure about the planar mode. There might be some complicated way to represent it with the 3-subsets of mode 0. - Neil _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
