[Mesa-dev] [PATCH 2/2] gallium: Replaced gl_rasterization_rules with lower_left_origin and half_pixel_center.

[Jose Fonseca]

----- Original Message -----
> ----- 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?

Forgot to say -- these are piglit tests.

Jose