On 02/09/2016 11:30 AM, Jose Fonseca wrote: > On 09/02/16 19:17, Axel Davy wrote: >> Hi, >> >> We'd need to do some formats conversion in gallium nine, and if possible >> we would like to do them in-place. >> >> unpack_rgba_8unorm/pack_rgba_8unorm doesn't seem to explicitly allow >> in-place conversion, >> but the generated code seems to be fine with that. >> >> Can we rely on these functions to be safe for in-place conversion ? >> Could we add that somewhere as requirement ? >> >> CC-ing vmware guys, as they probably know. >> >> Yours, >> >> Axel Davy > > It might work in practice now, but I don't think this is same it should > be dependent upon. > > Take BGRA <-> RGBA: currently we read the dword, swizzle, and write > dword back, but it's an implementation detail. One could imagine at > some point the implementation be changed to read/write bytes at a time, > which would break if done in place. > > > My recommendation is, if you want to do this things in place: malloc a > temp with the size of a row of pixels, convert into temp row then memcpy > into src.
The other option is to make this explicit and add a unit test to enforce the behavior. > You can even add util_convert_format_inplace() helper if you want. > > And if there's any hot-path (e.g., BGRA<->RGBA) just add a special code > path to this new util_convert_format_inplace that avoids the temp copy. > > Jose > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/mesa-dev _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
