On Fri, 2010-02-12 at 05:44 -0800, michal wrote: > Keith Whitwell wrote on 2010-02-12 14:28: > > 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?? > > > > > > You are right. > > Alternatively, follow the more sane API (GL apparently), assume 0001 as > default and use the 1111 infix to override.
That sounds good to me too. Thanks Michal, 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
