On Wed, Sep 1, 2010 at 7:54 PM, Luca Barbieri <l...@luca-barbieri.com> wrote: >> It still sounds that you're referring to sampling from a texture and not >> rendering/blending to it. Of course the are related (we only want one >> swizzled layout at most), but the current swizzled layout was chosen to >> make blending easy; and not to make texture sampling easy. >> >> No SoA swizzled layout makes texture sampling easier or more efficient. > > Yes, I incorrectly assumed that sampling were performed using the > swizzled SoA layout too, which is indeed not the case and probably > would be a bad idea. > > Perhaps always keeping the texture in a linear layout and converting > before/after processing tiles could be an option? It seems the current > code can do this, but only does in some cases (not totally sure).
We switched to this a little while ago, though the code is more structured towards the original approach so it isn't easy to tell. Z buffers are special as they are normally never accessed outside shaders, so they stay swizzled always. That's about it. > That would even allow to keep the tiles in a SoA floating point layout > without any significant RAM usage disadvantage. > This may perhaps be faster than the current scheme, since you don't > have to do format conversions during rendering (but you get a larger > cache footprint, and need to clamp anyway for correctness before and > after blending). Switching to this scheme was indeed a win. If nothing changes, this is where we'll stay but at some point I'll make the experiment of shading directly into the linear format. Keith _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
