[Mesa-dev] [PATCH RFC 2/3] glsl: Make gl_TexCoord compatibility-only

[Ian Romanick]

On 07/08/2013 10:40 AM, Paul Berry wrote:
> gl_TexCoord was deprecated in GLSL 1.30.  In GLSL 1.40 it was marked
> as ARB_compatibility-only, and in GLSL 1.50 and above it was marked as
> only appearing in the compatibility profile.  It has never appeared in
> GLSL ES.
>
> However, Mesa erroneously included it in all desktop versions of GLSL,
> even versions 1.40 and 1.50 (which do not currently support the
> compatibility profile).  This patch makes gl_TexCoord available in the
> compatibility profile (and GLSL versions 1.30 and prior) only.
>
> NOTE: although this is a simple bug fix, it probably isn't sensible to
> cherry-pick it to stable release branches, since its only effect is to
> cause incorrectly-written shaders to fail to compile.

I agree.

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

> ---
>   src/glsl/builtin_variables.cpp | 56 ++++++++++++++++++++++--------------------
>   1 file changed, 30 insertions(+), 26 deletions(-)
>
> diff --git a/src/glsl/builtin_variables.cpp b/src/glsl/builtin_variables.cpp
> index 58019c6..eccd15a 100644
> --- a/src/glsl/builtin_variables.cpp
> +++ b/src/glsl/builtin_variables.cpp
> @@ -748,20 +748,22 @@ generate_110_vs_variables(exec_list *instructions,
>      }
>      generate_110_uniforms(instructions, state, add_deprecated);
>
> -   /* From page 54 (page 60 of the PDF) of the GLSL 1.20 spec:
> -    *
> -    *     "As with all arrays, indices used to subscript gl_TexCoord must
> -    *     either be an integral constant expressions, or this array must be
> -    *     re-declared by the shader with a size. The size can be at most
> -    *     gl_MaxTextureCoords. Using indexes close to 0 may aid the
> -    *     implementation in preserving varying resources."
> -    */
> -   const glsl_type *const vec4_array_type =
> -      glsl_type::get_array_instance(glsl_type::vec4_type, 0);
> +   if (add_deprecated) {
> +      /* From page 54 (page 60 of the PDF) of the GLSL 1.20 spec:
> +       *
> +       *     "As with all arrays, indices used to subscript gl_TexCoord must
> +       *     either be an integral constant expressions, or this array must be
> +       *     re-declared by the shader with a size. The size can be at most
> +       *     gl_MaxTextureCoords. Using indexes close to 0 may aid the
> +       *     implementation in preserving varying resources."
> +       */
> +      const glsl_type *const vec4_array_type =
> +         glsl_type::get_array_instance(glsl_type::vec4_type, 0);
>
> -   add_variable(instructions, state->symbols,
> -		"gl_TexCoord", vec4_array_type, ir_var_shader_out,
> -                VARYING_SLOT_TEX0);
> +      add_variable(instructions, state->symbols,
> +                   "gl_TexCoord", vec4_array_type, ir_var_shader_out,
> +                   VARYING_SLOT_TEX0);
> +   }
>
>      generate_ARB_draw_buffers_variables(instructions, state, false,
>   				       vertex_shader);
> @@ -944,20 +946,22 @@ generate_110_fs_variables(exec_list *instructions,
>
>      generate_110_uniforms(instructions, state, add_deprecated);
>
> -   /* From page 54 (page 60 of the PDF) of the GLSL 1.20 spec:
> -    *
> -    *     "As with all arrays, indices used to subscript gl_TexCoord must
> -    *     either be an integral constant expressions, or this array must be
> -    *     re-declared by the shader with a size. The size can be at most
> -    *     gl_MaxTextureCoords. Using indexes close to 0 may aid the
> -    *     implementation in preserving varying resources."
> -    */
> -   const glsl_type *const vec4_array_type =
> -      glsl_type::get_array_instance(glsl_type::vec4_type, 0);
> +   if (add_deprecated) {
> +      /* From page 54 (page 60 of the PDF) of the GLSL 1.20 spec:
> +       *
> +       *     "As with all arrays, indices used to subscript gl_TexCoord must
> +       *     either be an integral constant expressions, or this array must be
> +       *     re-declared by the shader with a size. The size can be at most
> +       *     gl_MaxTextureCoords. Using indexes close to 0 may aid the
> +       *     implementation in preserving varying resources."
> +       */
> +      const glsl_type *const vec4_array_type =
> +         glsl_type::get_array_instance(glsl_type::vec4_type, 0);
>
> -   add_variable(instructions, state->symbols,
> -		"gl_TexCoord", vec4_array_type, ir_var_shader_in,
> -                VARYING_SLOT_TEX0);
> +      add_variable(instructions, state->symbols,
> +                   "gl_TexCoord", vec4_array_type, ir_var_shader_in,
> +                   VARYING_SLOT_TEX0);
> +   }
>
>      generate_ARB_draw_buffers_variables(instructions, state, false,
>   				       fragment_shader);
>