On 17/03/2008, Stefan Dösinger stefan@codeweavers.com wrote:
Am Montag, 17. März 2008 10:01:30 schrieb H. Verbeet:
Also, all the cards that are powerful enough to support a shader implementation of fixed function processing support GLSL vertex and fragment shaders, so realistically all you really need is a GLSL ffp replacement.
That's not quite true, my atifs replacement supports everything on the fragment side, and that card doesn't support GLSL(not even ARBfp).
Sure, but in that aspect it isn't really different from register combiners.
Also on the vertex side there are cards that have ARB only and not GLSL. I don't yet know if we can replace the fixed function vertex pipeline on r200 cards, as the 128 shader constants seem rather limiting, especially when it comes to indexed vertex blending. However, it should be able to do non-indexed vertex blending just fine, and we can get rid of the color conversion.
I think a useful ffp replacement should at least replace the vertex processing part. Extension s like ATI_fragment_shader and NV_register_combiners, etc. can already support pretty much all of fixed function fragment processing without having to integrate it in the shader backends.
In terms of replacing vertex processing, anything that still has dedicated hardware for fixed function processing isn't really powerful enough to run such an ffp replacement, either because of instruction count / number of constant limitations or simply execution speed. For nvidia hardware that basically means you'll need at least something like a GF5 or GF6.