[Mesa-dev] [PATCH 1/2] glsl: Fix varying struct locations when varying packing is disabled.

[Ilia Mirkin]

On Wed, Dec 30, 2015 at 6:26 AM, Kenneth Graunke <kenneth at whitecape.org> wrote:
> varying_matches::record tries to compute the number of components in
> each varying, which varying_matches::assign_locations uses to assign
> locations.  With varying packing, it uses glsl_type::component_slots()
> to come up with a reasonable value.
>
> Without varying packing, it fell back to an open-coded computation
> that didn't bother to handle structs at all.  I believe we can simply
> use 4 * glsl_type::count_attribute_slots(false), which already handles
> these cases correctly.
>
> Partially fixes rendering in GFXBench 4.0's tessellation benchmark.
> (NVE0 is almost right after this, but i965 is still mostly garbage.)
>
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> Cc: mesa-stable at lists.freedesktop.org
> Cc: Timothy Arceri <timothy.arceri at collabora.com>
> Cc: Ilia Mirkin <imirkin at alum.mit.edu>

That seems right... but 11.0/11.1 didn't have the
count_attribute_slots(true/false) thing -- only true :(

I'd be fine with nominating commit 5dc22cadb for 11.0/11.1 stable
though and then including this patch as well. Either way, this one is

Reviewed-by: Ilia Mirkin <imirkin at alum.mit.edu>

> ---
>  src/glsl/link_varyings.cpp | 15 ++-------------
>  1 file changed, 2 insertions(+), 13 deletions(-)
>
> diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
> index 9cc77fe..1ff25b8 100644
> --- a/src/glsl/link_varyings.cpp
> +++ b/src/glsl/link_varyings.cpp
> @@ -959,19 +959,8 @@ varying_matches::record(ir_variable *producer_var, ir_variable *consumer_var)
>           type = type->fields.array;
>        }
>
> -      if (type->is_array()) {
> -         slots = 1;
> -         while (type->is_array()) {
> -            slots *= type->length;
> -            type = type->fields.array;
> -         }
> -         slots *= type->matrix_columns;
> -      } else {
> -         slots = type->matrix_columns;
> -      }
> -      if (type->without_array()->is_dual_slot_double())
> -         slots *= 2;
> -      this->matches[this->num_matches].num_components = 4 * slots;
> +      slots = type->count_attribute_slots(false);
> +      this->matches[this->num_matches].num_components = slots * 4;
>     } else {
>        this->matches[this->num_matches].num_components
>           = var->type->component_slots();
> --
> 2.6.4
>