[Mesa-dev] [PATCH] glsl: Relax requirement on Centroid matching between shader stages

[Ian Romanick]

On 11/04/2015 01:04 AM, Marta Lofstedt wrote:
> From: Marta Lofstedt <marta.lofstedt at intel.com>
> 
> In OpenGL 4.4, section 4.5, the requirement for interpolation
> qualifiers to match over shader stages was removed.
> In OpenGL ES 3.1, section 9.2.1 there is a table showing that
> centroid does not have to match between shader stages.

I haven't checked this yet... does either spec provide guidance as to
what happens when only the vertex shader stage specifies centroid?  Is
the interpolation centroid or not?

...and are we doing the right thing? :)

> Also see bug 92743 for more discussions.

Please note this, after your s-o-b, as

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92743

I think this is also a candidate for stable:

Cc: mesa-stable at lists.freedesktop.org

> Signed-off-by: Marta Lofstedt <marta.lofstedt at linux.intel.com>
> ---
>  src/glsl/link_varyings.cpp | 14 --------------
>  1 file changed, 14 deletions(-)
> 
> diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
> index 7e77a67..d0edc71 100644
> --- a/src/glsl/link_varyings.cpp
> +++ b/src/glsl/link_varyings.cpp
> @@ -96,20 +96,6 @@ cross_validate_types_and_qualifiers(struct gl_shader_program *prog,
>        }
>     }
>  
> -   /* Check that all of the qualifiers match between stages.
> -    */
> -   if (input->data.centroid != output->data.centroid) {
> -      linker_error(prog,
> -                   "%s shader output `%s' %s centroid qualifier, "
> -                   "but %s shader input %s centroid qualifier\n",
> -                   _mesa_shader_stage_to_string(producer_stage),
> -                   output->name,
> -                   (output->data.centroid) ? "has" : "lacks",
> -                   _mesa_shader_stage_to_string(consumer_stage),
> -                   (input->data.centroid) ? "has" : "lacks");
> -      return;
> -   }
> -
>     if (input->data.sample != output->data.sample) {
>        linker_error(prog,
>                     "%s shader output `%s' %s sample qualifier, "
>