[Mesa-dev] [PATCH 3/8] Add support for the new builtins that EXT_blend_func_extended provides.

Ilia Mirkin imirkin at alum.mit.edu
Thu Nov 5 09:30:16 PST 2015


On Thu, Nov 5, 2015 at 12:16 PM, Ryan Houdek <sonicadvance1 at gmail.com> wrote:

subject: glsl: ...

> gl_MaxDualSourceDrawBuffersEXT - Maximum DS draw buffers supported
>
> Only for ESSL 1.0 it provides two builtins since you can't have user-defined
> color output variables
> gl_SecondaryFragColorEXT and gl_SecondaryFragDataEXT[MaxDSDrawBuffers]
> ---
>  src/glsl/ast_to_hir.cpp        | 16 +++++++++++
>  src/glsl/builtin_variables.cpp | 62 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 78 insertions(+)
>
> diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
> index 0306530..9ac7d80 100644
> --- a/src/glsl/ast_to_hir.cpp
> +++ b/src/glsl/ast_to_hir.cpp
> @@ -6973,6 +6973,8 @@ detect_conflicting_assignments(struct _mesa_glsl_parse_state *state,
>  {
>     bool gl_FragColor_assigned = false;
>     bool gl_FragData_assigned = false;
> +   bool gl_FragSecondaryColor_assigned = false;
> +   bool gl_FragSecondaryData_assigned = false;
>     bool user_defined_fs_output_assigned = false;
>     ir_variable *user_defined_fs_output = NULL;
>
> @@ -6990,6 +6992,10 @@ detect_conflicting_assignments(struct _mesa_glsl_parse_state *state,
>           gl_FragColor_assigned = true;
>        else if (strcmp(var->name, "gl_FragData") == 0)
>           gl_FragData_assigned = true;
> +       else if (strcmp(var->name, "gl_SecondaryFragColorEXT") == 0)
> +         gl_FragSecondaryColor_assigned = true;
> +       else if (strcmp(var->name, "gl_SecondaryFragDataEXT") == 0)
> +         gl_FragSecondaryData_assigned = true;
>        else if (!is_gl_identifier(var->name)) {
>           if (state->stage == MESA_SHADER_FRAGMENT &&
>               var->data.mode == ir_var_shader_out) {
> @@ -7021,11 +7027,21 @@ detect_conflicting_assignments(struct _mesa_glsl_parse_state *state,
>        _mesa_glsl_error(&loc, state, "fragment shader writes to both "
>                         "`gl_FragColor' and `%s'",
>                         user_defined_fs_output->name);
> +   } else if (gl_FragSecondaryColor_assigned && gl_FragSecondaryData_assigned) {
> +      _mesa_glsl_error(&loc, state, "fragment shader writes to both "
> +                       "`gl_FragSecondaryColorEXT' and"
> +                       " `gl_FragSecondaryDataEXT'");
>     } else if (gl_FragData_assigned && user_defined_fs_output_assigned) {
>        _mesa_glsl_error(&loc, state, "fragment shader writes to both "
>                         "`gl_FragData' and `%s'",
>                         user_defined_fs_output->name);
>     }
> +
> +   if ((gl_FragSecondaryColor_assigned || gl_FragSecondaryData_assigned) &&
> +       !state->EXT_blend_func_extended_enable) {
> +      _mesa_glsl_error(&loc, state,
> +                       "Dual source blending requires EXT_blend_func_extended");
> +   }
>  }
>
>
> diff --git a/src/glsl/builtin_variables.cpp b/src/glsl/builtin_variables.cpp
> index c30fb92..45c8dfb 100644
> --- a/src/glsl/builtin_variables.cpp
> +++ b/src/glsl/builtin_variables.cpp
> @@ -376,6 +376,11 @@ private:
>        return add_variable(name, type, ir_var_shader_out, slot);
>     }
>
> +   ir_variable *add_index_output(int slot, int index, const glsl_type *type, const char *name)
> +   {
> +      return add_index_variable(name, type, ir_var_shader_out, slot, index);
> +   }
> +
>     ir_variable *add_system_value(int slot, const glsl_type *type,
>                                   const char *name)
>     {
> @@ -384,6 +389,8 @@ private:
>
>     ir_variable *add_variable(const char *name, const glsl_type *type,
>                               enum ir_variable_mode mode, int slot);
> +   ir_variable *add_index_variable(const char *name, const glsl_type *type,
> +                             enum ir_variable_mode mode, int slot, int index);
>     ir_variable *add_uniform(const glsl_type *type, const char *name);
>     ir_variable *add_const(const char *name, int value);
>     ir_variable *add_const_ivec3(const char *name, int x, int y, int z);
> @@ -429,6 +436,46 @@ builtin_variable_generator::builtin_variable_generator(
>  {
>  }
>
> +ir_variable *
> +builtin_variable_generator::add_index_variable(const char *name,
> +                                         const glsl_type *type,
> +                                         enum ir_variable_mode mode, int slot, int index)
> +{
> +   ir_variable *var = new(symtab) ir_variable(type, name, mode);
> +   var->data.how_declared = ir_var_declared_implicitly;
> +
> +   switch (var->data.mode) {
> +   case ir_var_auto:
> +   case ir_var_shader_in:
> +   case ir_var_uniform:
> +   case ir_var_system_value:
> +      var->data.read_only = true;
> +      break;
> +   case ir_var_shader_out:
> +   case ir_var_shader_storage:
> +      break;
> +   default:
> +      /* The only variables that are added using this function should be
> +       * uniforms, shader storage, shader inputs, and shader outputs, constants
> +       * (which use ir_var_auto), and system values.
> +       */
> +      assert(0);
> +      break;
> +   }
> +
> +   var->data.location = slot;
> +   var->data.explicit_location = (slot >= 0);
> +   var->data.explicit_index = 1;
> +   var->data.index = index;
> +
> +   /* Once the variable is created an initialized, add it to the symbol table
> +    * and add the declaration to the IR stream.
> +    */
> +   instructions->push_tail(var);
> +
> +   symtab->add_variable(var);
> +   return var;
> +}
>
>  ir_variable *
>  builtin_variable_generator::add_variable(const char *name,
> @@ -580,6 +627,14 @@ builtin_variable_generator::generate_constants()
>           add_const("gl_MaxVaryingVectors",
>                     state->ctx->Const.MaxVarying);
>        }
> +
> +      /* EXT_blend_func_extended brings a built in constant
> +      * for determining number of dual source draw buffers

indent

> +      */
> +      if (state->EXT_blend_func_extended_enable) {
> +         add_const("gl_MaxDualSourceDrawBuffersEXT",
> +                   state->Const.MaxDualSourceDrawBuffers);
> +      }
>     } else {
>        add_const("gl_MaxVertexUniformComponents",
>                  state->Const.MaxVertexUniformComponents);
> @@ -1016,6 +1071,13 @@ builtin_variable_generator::generate_fs_special_vars()
>                   array(vec4_t, state->Const.MaxDrawBuffers), "gl_FragData");
>     }
>
> +   if (state->es_shader && state->language_version == 100 && state->EXT_blend_func_extended_enable) {
> +      add_index_output(FRAG_RESULT_DATA0, 1, vec4_t, "gl_SecondaryFragColorEXT");

Is there any difference between these two? Or only in the highly
theoretical case that multiple dual-source draw buffers can exist?

> +      add_index_output(FRAG_RESULT_DATA0, 1,
> +                       array(vec4_t, state->Const.MaxDualSourceDrawBuffers),
> +                       "gl_SecondaryFragDataEXT");
> +   }
> +
>     /* gl_FragDepth has always been in desktop GLSL, but did not appear in GLSL
>      * ES 1.00.
>      */
> --
> 2.5.0
>
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> mesa-dev at lists.freedesktop.org
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