[Mesa-dev] [PATCH 7/7] mesa: add KHR_no_error support for glUseProgram

[Nicolai Hähnle]

On 04.05.2017 05:34, Timothy Arceri wrote:
>
>
> On 04/05/17 13:31, Dave Airlie wrote:
>>> +/* The ARB_separate_shader_object spec says:
>>> + *
>>> + *     "The executable code for an individual shader stage is taken
>>> from
>>> + *     the current program for that stage.  If there is a current
>>> program
>>> + *     object established by UseProgram, that program is considered
>>> current
>>> + *     for all stages.  Otherwise, if there is a bound program pipeline
>>> + *     object (section 2.14.PPO), the program bound to the appropriate
>>> + *     stage of the pipeline object is considered current."
>>> + */
>>> +#define
>>> USE_PROGRAM(no_error)                                                \
>>> +   if (program)
>>> {                                                            \
>>> +      /* Attach shader state to the binding point
>>> */                         \
>>> +      _mesa_reference_pipeline_object(ctx, &ctx->_Shader,
>>> &ctx->Shader);     \
>>> +      /* Update the program
>>> */                                               \
>>> +      _mesa_use_shader_program(ctx,
>>> shProg);                                 \
>>> +   } else
>>> {                                                                  \
>>> +      /* Must be done first: detach the progam
>>> */                            \
>>> +      _mesa_use_shader_program(ctx,
>>> shProg);                                 \
>>> +      /* Unattach shader_state binding point
>>> */                              \
>>> +      _mesa_reference_pipeline_object(ctx,
>>> &ctx->_Shader,                    \
>>> +
>>> ctx->Pipeline.Default);                \
>>> +      /* If a pipeline was bound, rebind it
>>> */                               \
>>> +      if (ctx->Pipeline.Current)
>>> {                                           \
>>> +
>>> _mesa_BindProgramPipeline##no_error(ctx->Pipeline.Current->Name);   \
>>> +
>>> }                                                                      \
>>> +
>>> }
>>> \
>>> +
>>
>> why the macro, inline functions are a thing, or just one common
>> function that both entrypoints call.
>>
>
> So that we can avoid adding an if to call
>
> _mesa_BindProgramPipeline_no_error vs _mesa_BindProgramPipeline

I have to say I also don't like this very much. Do you have benchmarks 
to back up the usefulness of this?

This is where C++ templates would be great, because there could just be 
a boolean no_error template parameter. Maybe there's a way to get 
somewhere similar in C, even if it requires some compiler extensions?

Cheers,
Nicolai


>
>> Dave.
>>
>>> +void GLAPIENTRY
>>> +_mesa_UseProgram_no_error(GLuint program)
>>> +{
>>> +   GET_CURRENT_CONTEXT(ctx);
>>> +   struct gl_shader_program *shProg = NULL;
>>> +
>>> +   if (program) {
>>> +      shProg = _mesa_lookup_shader_program(ctx, program);
>>> +   }
>>> +
>>> +   USE_PROGRAM(_no_error)
>>> +}
>>> +
>>>
>>>   void GLAPIENTRY
>>>   _mesa_UseProgram(GLuint program)
>>>   {
>>>      GET_CURRENT_CONTEXT(ctx);
>>>      struct gl_shader_program *shProg = NULL;
>>>
>>>      if (MESA_VERBOSE & VERBOSE_API)
>>>         _mesa_debug(ctx, "glUseProgram %u\n", program);
>>>
>>> @@ -1875,44 +1915,21 @@ _mesa_UseProgram(GLuint program)
>>>            return;
>>>         }
>>>
>>>   #ifdef DEBUG
>>>         if (ctx->_Shader->Flags & GLSL_USE_PROG) {
>>>            print_shader_info(shProg);
>>>         }
>>>   #endif
>>>      }
>>>
>>> -   /* The ARB_separate_shader_object spec says:
>>> -    *
>>> -    *     "The executable code for an individual shader stage is
>>> taken from
>>> -    *     the current program for that stage.  If there is a current
>>> program
>>> -    *     object established by UseProgram, that program is
>>> considered current
>>> -    *     for all stages.  Otherwise, if there is a bound program
>>> pipeline
>>> -    *     object (section 2.14.PPO), the program bound to the
>>> appropriate
>>> -    *     stage of the pipeline object is considered current."
>>> -    */
>>> -   if (program) {
>>> -      /* Attach shader state to the binding point */
>>> -      _mesa_reference_pipeline_object(ctx, &ctx->_Shader,
>>> &ctx->Shader);
>>> -      /* Update the program */
>>> -      _mesa_use_shader_program(ctx, shProg);
>>> -   } else {
>>> -      /* Must be done first: detach the progam */
>>> -      _mesa_use_shader_program(ctx, shProg);
>>> -      /* Unattach shader_state binding point */
>>> -      _mesa_reference_pipeline_object(ctx, &ctx->_Shader,
>>> ctx->Pipeline.Default);
>>> -      /* If a pipeline was bound, rebind it */
>>> -      if (ctx->Pipeline.Current) {
>>> -         _mesa_BindProgramPipeline(ctx->Pipeline.Current->Name);
>>> -      }
>>> -   }
>>> +   USE_PROGRAM()
>>>   }
>>>
>>>
>>>   void GLAPIENTRY
>>>   _mesa_ValidateProgram(GLuint program)
>>>   {
>>>      GET_CURRENT_CONTEXT(ctx);
>>>      validate_program(ctx, program);
>>>   }
>>>
>>> diff --git a/src/mesa/main/shaderapi.h b/src/mesa/main/shaderapi.h
>>> index 99b4fe8..0a28185 100644
>>> --- a/src/mesa/main/shaderapi.h
>>> +++ b/src/mesa/main/shaderapi.h
>>> @@ -120,20 +120,22 @@ _mesa_IsProgram(GLuint name);
>>>
>>>   extern GLboolean GLAPIENTRY
>>>   _mesa_IsShader(GLuint name);
>>>
>>>   extern void GLAPIENTRY
>>>   _mesa_LinkProgram(GLuint programObj);
>>>
>>>   extern void GLAPIENTRY
>>>   _mesa_ShaderSource(GLuint, GLsizei, const GLchar* const *, const
>>> GLint *);
>>>
>>> +void GLAPIENTRY
>>> +_mesa_UseProgram_no_error(GLuint);
>>>   extern void GLAPIENTRY
>>>   _mesa_UseProgram(GLuint);
>>>
>>>   extern void GLAPIENTRY
>>>   _mesa_ValidateProgram(GLuint);
>>>
>>>
>>>   extern void GLAPIENTRY
>>>   _mesa_BindAttribLocation(GLuint program, GLuint, const GLchar *);
>>>
>>> --
>>> 2.9.3
>>>
>>> _______________________________________________
>>> mesa-dev mailing list
>>> mesa-dev at lists.freedesktop.org
>>> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev


-- 
Lerne, wie die Welt wirklich ist,
Aber vergiss niemals, wie sie sein sollte.