----- Original Message ----- > On 12.03.2012 13:26, Roland Scheidegger wrote: > > Hmm actually I think these new pipe formats are a mistake. > > Why do you need them and don't just use the existing R8G8_B8G8 and > > G8R8_G8B8? > > Do you really care if Y ends up in G channel instead of R? And if > > you do > > why don't you just use a sampler swizzle? > > The R8G8_B8G8 and G8R8_G8B8 formats are there because these > > correspond > > to the subsampled DX10 formats. I just see absolutely no point in > > introducing similar formats which just have different channel > > mapping - > > we generally don't have arbitrary swizzled formats, with the > > exception > > of "old" ones which can be used for legacy purposes. But no such > > case > > can be made for these new formats. > Well, we definitely already have separate formats for different > channel > mappings. otherwise we should handle the difference between RGBA and > BGRA with sampler swizzle’s also. > > > (I just checked the i965 docs which doesn't support sampler > > swizzling, > > and in fact these new formats wouldn't help you there neither, > > since all > > 4 subsampled ycbcr format map Y to the green channel. So with hw > > supporting sampler swizzling, these formats don't buy you anything, > > and > > with hw not supporting it they don't help neither as no hardware > > out > > there supports them anyway.) > > Or is there another reason why you need these formats I'm missing? > Nope, not really I just added them for consistency with the existing > format handling, and it actually makes the implementation of YUV -> > RGB > conversion a bit easier.
I think it's fine to have additional formats if they help in anyway. I certainly rather have more formats than, e.g., jamming multiple semantics on an existing format. If formats eventually become unused we can always remove them. Jose _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
