[Mesa-dev] [PATCH 19/28] glsl: add support for explicit components to frag outputs

[Anuj Phogat]

On Mon, Dec 28, 2015 at 9:00 PM, Timothy Arceri
<timothy.arceri at collabora.com> wrote:
> ---
>  src/glsl/linker.cpp | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 55 insertions(+), 1 deletion(-)
>
> diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
> index 41ff057..44dd7f0 100644
> --- a/src/glsl/linker.cpp
> +++ b/src/glsl/linker.cpp
> @@ -2411,7 +2411,12 @@ assign_attribute_or_color_locations(gl_shader_program *prog,
>        }
>     } to_assign[16];
>
> +   /* Temporary array for the set of attributes that have locations assigned.
> +    */
> +   ir_variable *assigned[16];
> +
>     unsigned num_attr = 0;
> +   unsigned assigned_attr = 0;
>
>     foreach_in_list(ir_instruction, node, sh->ir) {
>        ir_variable *const var = node->as_variable();
> @@ -2573,7 +2578,53 @@ assign_attribute_or_color_locations(gl_shader_program *prog,
>              * attribute overlaps any previously allocated bits.
>              */
>             if ((~(use_mask << attr) & used_locations) != used_locations) {
> -               if (target_index == MESA_SHADER_FRAGMENT ||
> +               if (target_index == MESA_SHADER_FRAGMENT && !prog->IsES) {
> +                  /* From section 4.4.2 (Output Layout Qualifiers) of the GLSL
> +                   * 4.40 spec:
> +                   *
> +                   *    "Additionally, for fragment shader outputs, if two
> +                   *    variables are placed within the same location, they
> +                   *    must have the same underlying type (floating-point or
> +                   *    integer). No component aliasing of output variables or
> +                   *    members is allowed.
> +                   */
> +                  int frag_out_end_loc = (var->type->is_array() ?
> +                     var->type->arrays_of_arrays_size() : 1) +
> +                     var->data.location;
> +
> +                  for (unsigned i = 0; i < assigned_attr; i++) {
> +                     for (int j = var->data.location; j < frag_out_end_loc;
> +                          j++) {
> +                        if (assigned[i]->data.location == j) {
I find assigned[i]->data.location == var->data.location more readable.

> +                           if (assigned[i]->type->without_array()->base_type !=
> +                               var->type->without_array()->base_type) {
> +                              linker_error(prog,
> +                                           "types do not match for aliased"
> +                                           " %ss %s and %s\n", string,
> +                                           assigned[i]->name, var->name);
> +                              return false;
> +                           }
> +
> +                           if ((assigned[i]->data.location_frac ==
> +                                var->data.location_frac) ||
> +                              ((assigned[i]->data.location_frac <
> +                                var->data.location_frac) &&
> +                                ((assigned[i]->data.location_frac +
> +                                  assigned[i]->type->vector_elements) >
> +                                 var->data.location_frac))) {
> +                              linker_error(prog,
> +                                           "overlapping component is "
> +                                           "assigned to %ss %s and %s "
> +                                           "(component=%d)\n",
> +                                           string, assigned[i]->name,
> +                                           var->name,
> +                                           var->data.location_frac);
> +                              return false;
> +                           }
> +                        }
> +                     }
> +                  }
> +               } else if (target_index == MESA_SHADER_FRAGMENT ||
>                     (prog->IsES && prog->Version >= 300)) {
>                    linker_error(prog,
>                                 "overlapping location is assigned "
> @@ -2614,6 +2665,9 @@ assign_attribute_or_color_locations(gl_shader_program *prog,
>                 double_storage_locations |= (use_mask << attr);
>          }
>
> +         assigned[assigned_attr] = var;
> +         assigned_attr++;
> +
>          continue;
>        }
>
> --
> 2.4.3
>
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Reviewed-by: Anuj Phogat <anuj.phogat at gmail.com>