[Mesa-dev] [PATCH 03/11] mesa: Add support for glUniformBlockBinding() and the API to get it back.

[Kenneth Graunke]

On 07/20/2012 03:33 PM, Eric Anholt wrote:
> Fixes piglit ARB_uniform_buffer_object/uniformbufferbinding.
> ---
>  src/mesa/main/uniforms.c |   95 ++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 95 insertions(+)
> 
> diff --git a/src/mesa/main/uniforms.c b/src/mesa/main/uniforms.c
> index ccbd753..940cb07 100644
> --- a/src/mesa/main/uniforms.c
> +++ b/src/mesa/main/uniforms.c
> @@ -41,6 +41,7 @@
>  #include "main/shaderapi.h"
>  #include "main/shaderobj.h"
>  #include "main/uniforms.h"
> +#include "main/enums.h"
>  #include "ir_uniform.h"
>  #include "glsl_types.h"
>  
> @@ -583,6 +584,98 @@ _mesa_GetUniformIndices(GLuint program,
>     }
>  }
>  
> +static void GLAPIENTRY
> +_mesa_UniformBlockBinding(GLuint program,
> +			  GLuint uniformBlockIndex,
> +			  GLuint uniformBlockBinding)
> +{
> +   GET_CURRENT_CONTEXT(ctx);
> +   struct gl_shader_program *shProg;
> +
> +   if (!ctx->Extensions.ARB_uniform_buffer_object) {
> +      _mesa_error(ctx, GL_INVALID_OPERATION, "glUniformBlockBinding");
> +      return;
> +   }
> +
> +   shProg = _mesa_lookup_shader_program_err(ctx, program,
> +					    "glUniformBlockBinding");
> +   if (!shProg)
> +      return;
> +
> +   if (uniformBlockIndex >= shProg->NumUniformBlocks) {
> +      _mesa_error(ctx, GL_INVALID_VALUE,
> +		  "glUniformBlockBinding(block index %d >= %d)",
> +		  uniformBlockIndex, shProg->NumUniformBlocks);
> +      return;
> +   }
> +
> +   if (uniformBlockBinding >= ctx->Const.MaxUniformBufferBindings) {
> +      _mesa_error(ctx, GL_INVALID_VALUE,
> +		  "glUniformBlockBinding(block binding %d >= %d)",
> +		  uniformBlockBinding, ctx->Const.MaxUniformBufferBindings);
> +      return;
> +   }
> +
> +   if (shProg->UniformBlocks[uniformBlockIndex].Binding !=
> +       uniformBlockBinding) {
> +      int i;
> +
> +      FLUSH_VERTICES(ctx, _NEW_BUFFER_OBJECT);
> +      shProg->UniformBlocks[uniformBlockIndex].Binding = uniformBlockBinding;

I'd almost expect to see a _NEW_PROGRAM_CONSTANTS when a new uniform
buffer gets bound.  Then again, that would cause re-uploading of all the
non-UBO uniforms, which is pointless and expensive.  Looking at the i965
backend, it looks like _NEW_PROGRAM_CONSTANTS mostly deals with push
constants, and your new patch for UBOs properly uses this flag.  So it
should be fine.

Everything else looks good.  For the series:
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

> +
> +      for (i = 0; i < MESA_SHADER_TYPES; i++) {
> +	 int stage_index = shProg->UniformBlockStageIndex[i][uniformBlockIndex];
> +
> +	 if (stage_index != -1) {
> +	    struct gl_shader *sh = shProg->_LinkedShaders[i];
> +	    sh->UniformBlocks[stage_index].Binding = uniformBlockBinding;
> +	 }
> +      }
> +   }
> +}
> +
> +static void GLAPIENTRY
> +_mesa_GetActiveUniformBlockiv(GLuint program,
> +			      GLuint uniformBlockIndex,
> +			      GLenum pname,
> +			      GLint *params)
> +{
> +   GET_CURRENT_CONTEXT(ctx);
> +   struct gl_shader_program *shProg;
> +   struct gl_uniform_block *block;
> +
> +   if (!ctx->Extensions.ARB_uniform_buffer_object) {
> +      _mesa_error(ctx, GL_INVALID_OPERATION, "glGetActiveUniformBlockiv");
> +      return;
> +   }
> +
> +   shProg = _mesa_lookup_shader_program_err(ctx, program,
> +					    "glGetActiveUniformBlockiv");
> +   if (!shProg)
> +      return;
> +
> +   if (uniformBlockIndex >= shProg->NumUniformBlocks) {
> +      _mesa_error(ctx, GL_INVALID_VALUE,
> +		  "glGetActiveUniformBlockiv(block index %d >= %d)",
> +		  uniformBlockIndex, shProg->NumUniformBlocks);
> +      return;
> +   }
> +
> +   block = &shProg->UniformBlocks[uniformBlockIndex];
> +
> +   switch (pname) {
> +   case GL_UNIFORM_BLOCK_BINDING:
> +      params[0] = block->Binding;
> +      return;
> +
> +   default:
> +      _mesa_error(ctx, GL_INVALID_ENUM,
> +		  "glGetActiveUniformBlockiv(pname 0x%x (%s))",
> +		  pname, _mesa_lookup_enum_by_nr(pname));
> +      return;
> +   }
> +}
> +
>  /**
>   * Plug in shader uniform-related functions into API dispatch table.
>   */
> @@ -644,6 +737,8 @@ _mesa_init_shader_uniform_dispatch(struct _glapi_table *exec)
>     SET_GetUniformBlockIndex(exec, _mesa_GetUniformBlockIndex);
>     SET_GetUniformIndices(exec, _mesa_GetUniformIndices);
>     SET_GetActiveUniformsiv(exec, _mesa_GetActiveUniformsiv);
> +   SET_GetActiveUniformBlockiv(exec, _mesa_GetActiveUniformBlockiv);
> +   SET_UniformBlockBinding(exec, _mesa_UniformBlockBinding);
>  
>  #endif /* FEATURE_GL */
>  }
>