On Fri, 2010-02-12 at 05:09 -0800, michal wrote: > Keith Whitwell wrote on 2010-02-12 13:39: > > On Fri, 2010-02-12 at 04:32 -0800, Micha?? Kr??l wrote: > > > >> Module: Mesa > >> Branch: master > >> Commit: aa0b671422880b99dc178d43d1e4e1a3f766bf7f > >> URL: > >> http://cgit.freedesktop.org/mesa/mesa/commit/?id=aa0b671422880b99dc178d43d1e4e1a3f766bf7f > >> > >> Author: Michal Krol <mic...@vmware.com> > >> Date: Fri Feb 12 13:32:35 2010 +0100 > >> > >> util: Fix descriptors for R32_FLOAT and R32G32_FLOAT formats. > >> > > > > Michal, > > > > Is this more like two different users expecting two different results in > > those unused columns? > > > > In particular, we definitely require the missing elements to be extended > > to (0,0,0,1) when fetching vertex data, and probably also in OpenGL > > texture sampling (if we supported these formats for that). > > > > > Gallium should follow D3D rules, so I've been following D3D here. Also, > util_unpack_color_ub() in u_pack_color.h already sets the remaining > fields to 0xff. > > Note that D3D doesn't have the problem with expanding vertex attribute > data since you can't have X or XY vertex positions, only XYZ (with W > extended to 1 as in GL) and XYZW.
But surely D3D permits two-component texture coordinates, which would be PIPE_FORMAT_R32G32_FLOAT, and expanded as (r,g,0,1)... > > Brian added a table of differences between GL and other APIs recently to > > gallium/docs - does your change agree with that? > > > > > Where's that exactly, I can't find it? It seems like we'd want to be able to support both usages - the alternative in texture sampling would be forcing the state tracker to generate varients of the shader when 2-component textures are bound. I would say that's an unreasonable requirement on the state tracker. It seems like in GL would want (0,0,0,1) expansion everywhere, but D3D would want differing expansions in different parts of the pipeline. That indicates a single flag in the context somewhere isn't sufficient to choose between the two. Maybe there need to be two versions of these PIPE_FORMAT_ enums to capture the different values in the missing components? EG: PIPE_FORMAT_R32G32_0001_FLOAT PIPE_FORMAT_R32G32_1111_FLOAT ? or something along those lines?? Keith ------------------------------------------------------------------------------ SOLARIS 10 is the OS for Data Centers - provides features such as DTrace, Predictive Self Healing and Award Winning ZFS. Get Solaris 10 NOW http://p.sf.net/sfu/solaris-dev2dev _______________________________________________ Mesa3d-dev mailing list Mesa3d-dev@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
