[Mesa-dev] [PATCH] draw: implement vertex color clamping

Keith Whitwell keithw at vmware.com
Wed Mar 30 05:45:50 PDT 2011


On Wed, 2011-03-30 at 14:33 +0200, Marek Olšák wrote:
> From: Luca Barbieri <luca at luca-barbieri.com>
> 
> Disclaimer:
>   I will not push this code if this patch does not get any attention,
>   because I cannot say if it is 100% correct (the code is not mine).
>   However last time I checked, it passed all the related tests.
>   Also, the SSE and PPC paths are disabled with this code.
>   -Marek
> 
> Squashed commit of the following:
> 
> commit 737c0c6b7d591ac0fc969a7590e1691eeef0ce5e
> Author: Luca Barbieri <luca at luca-barbieri.com>
> Date:   Fri Aug 27 02:13:57 2010 +0200
> 
>     draw: disable SSE and PPC paths (use LLVM instead)
> 
>     These paths don't support vertex clamping, and are anyway
>     obsoleted by LLVM.
> 
>     If you want to re-enable them, add vertex clamping and test that it
>     works with the ARB_color_buffer_float piglit tests.
> 
> commit fed3486a7ca0683b403913604a26ee49a3ef48c7
> Author: Luca Barbieri <luca at luca-barbieri.com>
> Date:   Thu Aug 26 18:27:38 2010 +0200
> 
>     draw_llvm: respect vertex color clamp
> 
> commit ef0efe9f3d1d0f9b40ebab78940491d2154277a9
> Author: Luca Barbieri <luca at luca-barbieri.com>
> Date:   Thu Aug 26 18:26:43 2010 +0200
> 
>     draw: respect vertex clamping in interpreter path
> ---
>  src/gallium/auxiliary/draw/draw_llvm.c    |   35 ++++++++++++++++++++++++++--
>  src/gallium/auxiliary/draw/draw_llvm.h    |    1 +
>  src/gallium/auxiliary/draw/draw_vs.c      |    7 +++++
>  src/gallium/auxiliary/draw/draw_vs_exec.c |   22 ++++++++++++++----
>  4 files changed, 57 insertions(+), 8 deletions(-)
> 
> diff --git a/src/gallium/auxiliary/draw/draw_llvm.c b/src/gallium/auxiliary/draw/draw_llvm.c
> index a5217c1..27c5f3b 100644
> --- a/src/gallium/auxiliary/draw/draw_llvm.c
> +++ b/src/gallium/auxiliary/draw/draw_llvm.c
> @@ -438,7 +438,8 @@ generate_vs(struct draw_llvm *llvm,
>              const LLVMValueRef (*inputs)[NUM_CHANNELS],
>              LLVMValueRef system_values_array,
>              LLVMValueRef context_ptr,
> -            struct lp_build_sampler_soa *draw_sampler)
> +            struct lp_build_sampler_soa *draw_sampler,
> +            boolean clamp_vertex_color)
>  {
>     const struct tgsi_token *tokens = llvm->draw->vs.vertex_shader->state.tokens;
>     struct lp_type vs_type;
> @@ -474,6 +475,30 @@ generate_vs(struct draw_llvm *llvm,
>                       outputs,
>                       sampler,
>                       &llvm->draw->vs.vertex_shader->info);
> +
> +   if(clamp_vertex_color)
> +   {
> +      LLVMValueRef out;
> +      unsigned chan, attrib;
> +      struct lp_build_context bld;
> +      struct tgsi_shader_info* info = &llvm->draw->vs.vertex_shader->info;
> +      lp_build_context_init(&bld, llvm->gallivm, vs_type);
> +
> +      for (attrib = 0; attrib < info->num_outputs; ++attrib) {
> +         for(chan = 0; chan < NUM_CHANNELS; ++chan) {
> +            if(outputs[attrib][chan]) {
> +               switch (info->output_semantic_name[attrib]) {
> +               case TGSI_SEMANTIC_COLOR:
> +               case TGSI_SEMANTIC_BCOLOR:
> +                  out = LLVMBuildLoad(builder, outputs[attrib][chan], "");
> +                  out = lp_build_clamp(&bld, out, bld.zero, bld.one);
> +                  LLVMBuildStore(builder, out, outputs[attrib][chan]);
> +                  break;
> +               }
> +            }
> +         }
> +      }
> +   }
>  }
>  
>  #if DEBUG_STORE
> @@ -1235,7 +1260,8 @@ draw_llvm_generate(struct draw_llvm *llvm, struct draw_llvm_variant *variant)
>                    ptr_aos,
>                    system_values_array,
>                    context_ptr,
> -                  sampler);
> +                  sampler,
> +                  variant->key.clamp_vertex_color);
>  
>        /* store original positions in clip before further manipulation */
>        store_clip(gallivm, io, outputs);
> @@ -1446,7 +1472,8 @@ draw_llvm_generate_elts(struct draw_llvm *llvm, struct draw_llvm_variant *varian
>                    ptr_aos,
>                    system_values_array,
>                    context_ptr,
> -                  sampler);
> +                  sampler,
> +                  variant->key.clamp_vertex_color);
>  
>        /* store original positions in clip before further manipulation */
>        store_clip(gallivm, io, outputs);
> @@ -1524,6 +1551,8 @@ draw_llvm_make_variant_key(struct draw_llvm *llvm, char *store)
>  
>     key = (struct draw_llvm_variant_key *)store;
>  
> +   key->clamp_vertex_color = llvm->draw->rasterizer->clamp_vertex_color; /**/
> +
>     /* Presumably all variants of the shader should have the same
>      * number of vertex elements - ie the number of shader inputs.
>      */
> diff --git a/src/gallium/auxiliary/draw/draw_llvm.h b/src/gallium/auxiliary/draw/draw_llvm.h
> index e8623e7..643a9ef 100644
> --- a/src/gallium/auxiliary/draw/draw_llvm.h
> +++ b/src/gallium/auxiliary/draw/draw_llvm.h
> @@ -162,6 +162,7 @@ struct draw_llvm_variant_key
>  {
>     unsigned nr_vertex_elements:8;
>     unsigned nr_samplers:8;
> +   unsigned clamp_vertex_color:8;
>     unsigned clip_xy:1;
>     unsigned clip_z:1;
>     unsigned clip_user:1;

Why are there 8 bits for this?

I'd suggest 1 bit is sufficient, and that you should take one bit from
"pad" to make space for it.


> diff --git a/src/gallium/auxiliary/draw/draw_vs.c b/src/gallium/auxiliary/draw/draw_vs.c
> index 7caad6f..1763dbc 100644
> --- a/src/gallium/auxiliary/draw/draw_vs.c
> +++ b/src/gallium/auxiliary/draw/draw_vs.c
> @@ -104,11 +104,18 @@ draw_create_vertex_shader(struct draw_context *draw,
>     }
>  
>     if (!draw->pt.middle.llvm) {
> +#if 0
> +/* these paths don't support vertex clamping
> + * TODO: either add it, or remove them completely
> + * use LLVM instead if you want performance
> + * use exec instead if you want debugging/more correctness
> + */
>  #if defined(PIPE_ARCH_X86)
>        vs = draw_create_vs_sse( draw, shader );
>  #elif defined(PIPE_ARCH_PPC)
>        vs = draw_create_vs_ppc( draw, shader );
>  #endif
> +#endif

Please god, let's just kill those paths.

>     }
>  #if HAVE_LLVM
>     else {
> diff --git a/src/gallium/auxiliary/draw/draw_vs_exec.c b/src/gallium/auxiliary/draw/draw_vs_exec.c
> index c41d7c4..d9c4209 100644
> --- a/src/gallium/auxiliary/draw/draw_vs_exec.c
> +++ b/src/gallium/auxiliary/draw/draw_vs_exec.c
> @@ -95,6 +95,7 @@ vs_exec_run_linear( struct draw_vertex_shader *shader,
>     struct tgsi_exec_machine *machine = evs->machine;
>     unsigned int i, j;
>     unsigned slot;
> +   boolean clamp_vertex_color = shader->draw->rasterizer->clamp_vertex_color;
>  
>     tgsi_exec_set_constant_buffers(machine, PIPE_MAX_CONSTANT_BUFFERS,
>                                    constants, const_size);
> @@ -151,11 +152,22 @@ vs_exec_run_linear( struct draw_vertex_shader *shader,
>         */
>        for (j = 0; j < max_vertices; j++) {
>           for (slot = 0; slot < shader->info.num_outputs; slot++) {
> -            output[slot][0] = machine->Outputs[slot].xyzw[0].f[j];
> -            output[slot][1] = machine->Outputs[slot].xyzw[1].f[j];
> -            output[slot][2] = machine->Outputs[slot].xyzw[2].f[j];
> -            output[slot][3] = machine->Outputs[slot].xyzw[3].f[j];
> -
> +            unsigned name = shader->info.output_semantic_name[slot];
> +            if(clamp_vertex_color &&
> +                  (name == TGSI_SEMANTIC_COLOR || name == TGSI_SEMANTIC_BCOLOR))
> +            {
> +               output[slot][0] = CLAMP(machine->Outputs[slot].xyzw[0].f[j], 0.0f, 1.0f);
> +               output[slot][1] = CLAMP(machine->Outputs[slot].xyzw[1].f[j], 0.0f, 1.0f);
> +               output[slot][2] = CLAMP(machine->Outputs[slot].xyzw[2].f[j], 0.0f, 1.0f);
> +               output[slot][3] = CLAMP(machine->Outputs[slot].xyzw[3].f[j], 0.0f, 1.0f);
> +            }
> +            else
> +            {
> +               output[slot][0] = machine->Outputs[slot].xyzw[0].f[j];
> +               output[slot][1] = machine->Outputs[slot].xyzw[1].f[j];
> +               output[slot][2] = machine->Outputs[slot].xyzw[2].f[j];
> +               output[slot][3] = machine->Outputs[slot].xyzw[3].f[j];
> +            }
>           }
>  
>  #if 0



Otherwise, it looks good to me.

Keith



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