> On r300->r500, if there are both a vertex shader output and sprite coords at > the same varying index, the output takes precedence, meaning that it behaves > as if sprite coords were disabled. This is OK because Gallium doesn't > specify which one to write to FS if there are both at the same slot. If you > think that sprite coords should take precedence instead, I could remap them > to another slot, but I need to think about it little more to see how to > implement the remapping. It's not as easy because vertex shader outputs > cannot be disabled once they are written to in the vertex shader. As far as I can tell, GL requires that sprite coordinates take precedence over ARB_vertex_program outputs. Why do things work right now, if Gallium and r300-r500 behave as you explained?
> Whatever will be the final solution, please consider that ideally we should > only have one way to setup sprite coords in gallium. If we had a special > shader semantic for PNTC, we should fix the texenv (fixed-function) program > to use the new semantic too and abandon sprite_coord_enable. Having 2 ways > to program point sprites, one for GLSL and another for everything else, is > no good. What about ARB_vp/ARB_fp? You would need to recompile the fragment shader when you change the sprite coord replacement settings in your proposal, if I understand it correctly. This might actually be good, but is a significant change. Also, doesn't sprite coord replacement also affect gl_TexCoord in GLSL? _______________________________________________ mesa-dev mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/mesa-dev
