Same as Dave. The first one fails, the second one (-use_fbo) passes. I just hope lower_left_origin doesn't affect the Y axis of the viewport, scissor and gl_FragCoord. If it does, a PIPE_CAP would be useful to keep the current behavior.
Marek On Sun, Apr 21, 2013 at 9:36 AM, Jose Fonseca <jfons...@vmware.com> wrote: > ----- Original Message ----- >> Do we really need the lower_left_origin state? I think I can't >> implement it for radeon and it's the kind of stuff that should be >> taken care of by the state tracker anyway. > > My understanding is that hardware had switches for this sort of thing. It's > really hard to provide fully-conforming rasterization for opengl, dx9 & dx10 > without it. > > If your hardware allows to put a negative pitch on rendertargets, then that > should also do it. > > If you know what is the hardware's sub-pixel rasterization resolution, then > adding a vertical bias equal to that amount, depending on this state, would > give a very close approximation. (This would get the top/bottom edges right, > at expense of small inaccuracies on non-horizontal edges) > >> Isn't it sufficient to just >> set a viewport which is upside down, like we do now? > > I'm not aware of rasterization top-left rule being affected by the viewport > flipping. > > Do both > > ./bin/triangle-rasterization -auto > ./bin/triangle-rasterization -use_fbo -auto > > currently work for you? > > > If drivers don't provide this state, the only way to workaround it I know > would be to store textures (or drawables?) up-side down, and flip them on > gl(Get)TexImage & friends. This would be like using a cannon to shoot a fly > (a lot of work and a lot of overheads for a small correctness detail). I > think the drivers are better equipped to handle this. > > And you always have the option of merely ignoring this state. Top-left rule > correct rasterization has, after all, been ignored till date, and nobody > cared. > > > For the record, my motivation here is simple: llvmpipe gets the right > behavior on GL drawables, and fails on GL FBOs & D3D 9/10. I want to get the > right behavior on D3D 9/10 without causing regressions on GL drawables. > > BTW, I'd imagine that if hardware rasterizer behavior is hardcoded to > anything, it would be to D3D 9/10 behavior. That is, they would get GL FBO > right, but drawables wrong. > > > Jose _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
