On Thu, Jul 9, 2015 at 5:05 PM, Marek Olšák <mar...@gmail.com> wrote: > I'd like to discuss one more thing that will affect whether image > slots will be global (shared by all shaders) or not. > > Which image unit an image uniform uses is not a compile-time thing, > but it's specified later using glUniform1i. That means we need a > per-shader table that maps image uniforms to global image units. One > possible solution is to add this pipe_context function: > > void (*set_shader_image_mapping)( > struct pipe_context *, unsigned shader, > unsigned start_decl_index, unsigned count, > unsigned *decl_to_slot_mapping); > > This is only required if the shader image slots are global and not > per-shader. (if they are per-shader, st/mesa can reorder the slots for > each shader independently just like it already does for textures and > UBOs) Shader storage buffer objects suffer from the same issue. Atomic > counters don't. > > Therefore, image slots must be per-shader (like sampler slots) to > avoid this craziness and keep things simple.
I think that's reasonable. The image slots can be fixed at compile-time (like sampler slots), and we can just stick the right images into the right places. But in order to do that, we need the per-stage mapping, so making it like sampler views seems reasonable. -ilia _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
