[Mesa-dev] [PATCH] glsl: double-precision values don't support interpolation

[Timothy Arceri]

On Wed, 2016-01-27 at 14:55 +0100, Samuel Iglesias Gonsálvez wrote:
> ARB_gpu_shader_fp64 spec says:
> 
>   "This extension does not support interpolation of double-precision
>   values; doubles used as fragment shader inputs must be qualified as
>   "flat"."
> 
> Fixes the regressions added by commit 781d278:
> 
> arb_gpu_shader_fp64-double-gettransformfeedbackvarying
> arb_gpu_shader_fp64-tf-interleaved
> arb_gpu_shader_fp64-tf-interleaved-aligned
> arb_gpu_shader_fp64-tf-separate
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93878
> Signed-off-by: Samuel Iglesias Gonsálvez <siglesias at igalia.com>

Thanks for taking another look at this Samuel :) This looks like the
correct change to me. It would be really nice to have at least one of
the above tests to be modified to have an SSO subtest.

Anyway this patch is:

Reviewed-by: Timothy Arceri <timothy.arceri at collabora.com>


> ---
>  src/compiler/glsl/link_varyings.cpp | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/src/compiler/glsl/link_varyings.cpp
> b/src/compiler/glsl/link_varyings.cpp
> index 264b69c..a4c730f 100644
> --- a/src/compiler/glsl/link_varyings.cpp
> +++ b/src/compiler/glsl/link_varyings.cpp
> @@ -967,11 +967,16 @@ varying_matches::record(ir_variable
> *producer_var, ir_variable *consumer_var)
>        return;
>     }
>  
> -   if ((consumer_var == NULL && producer_var->type-
> >contains_integer()) ||
> +   bool needs_flat_qualifier = consumer_var == NULL &&
> +      (producer_var->type->contains_integer() ||
> +       producer_var->type->contains_double());
> +
> +   if (needs_flat_qualifier ||
>         (consumer_stage != -1 && consumer_stage !=
> MESA_SHADER_FRAGMENT)) {
>        /* Since this varying is not being consumed by the fragment
> shader, its
>         * interpolation type varying cannot possibly affect
> rendering.
> -       * Also, this variable is non-flat and is (or contains) an
> integer.
> +       * Also, this variable is non-flat and is (or contains) an
> integer
> +       * or a double.
>         * If the consumer stage is unknown, don't modify the
> interpolation
>         * type as it could affect rendering later with separate
> shaders.
>         *