[Mesa-dev] [PATCH v2 04/11] glsl: Pack integer and double varyings as flat even if interpolation mode is none

[Ian Romanick]

On 06/16/2016 12:07 PM, Ian Romanick wrote:
> From: Ian Romanick <ian.d.romanick at intel.com>
> 
> v2: Also update varying_matches::compute_packing_class().  Suggested by
> Timothy Arceri.
> 
> Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96358
> Cc: "12.0" <mesa-stable at lists.freedesktop.org>
> Cc: Gregory Hainaut <gregory.hainaut at gmail.com>
> Cc: Ilia Mirkin <imirkin at alum.mit.edu>
> ---
>  src/compiler/glsl/ir.h                      |  7 +++++++
>  src/compiler/glsl/link_varyings.cpp         |  3 ++-
>  src/compiler/glsl/lower_packed_varyings.cpp | 11 ++++++-----
>  3 files changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/src/compiler/glsl/ir.h b/src/compiler/glsl/ir.h
> index 3629356..e5b8154 100644
> --- a/src/compiler/glsl/ir.h
> +++ b/src/compiler/glsl/ir.h
> @@ -590,6 +590,13 @@ public:
>        return this->u.state_slots;
>     }
>  
> +   inline bool is_interpolation_flat() const
> +   {
> +      return this->data.interpolation == INTERP_QUALIFIER_FLAT ||
> +             this->type->contains_integer() ||
> +             this->type->contains_double();
> +   }
> +
>     inline bool is_name_ralloced() const
>     {
>        return this->name != ir_variable::tmp_name;
> diff --git a/src/compiler/glsl/link_varyings.cpp b/src/compiler/glsl/link_varyings.cpp
> index ef8bdbe..84686ee 100644
> --- a/src/compiler/glsl/link_varyings.cpp
> +++ b/src/compiler/glsl/link_varyings.cpp
> @@ -1610,7 +1610,8 @@ varying_matches::compute_packing_class(const ir_variable *var)
>     unsigned packing_class = var->data.centroid | (var->data.sample << 1) |
>                              (var->data.patch << 2);
>     packing_class *= 4;
> -   packing_class += var->data.interpolation;
> +   packing_class += var->is_interpolation_flat()
> +      ? INTERP_QUALIFIER_FLAT : data.interpolation;

I had fixed the two bugs in this line, but I didn't squash the !fixup
patch before sending this out.  This should obviously be:

   packing_class += var->is_interpolation_flat()
      ? unsigned(INTERP_QUALIFIER_FLAT) : var->data.interpolation;

D'oh!

>     return packing_class;
>  }
>  
> diff --git a/src/compiler/glsl/lower_packed_varyings.cpp b/src/compiler/glsl/lower_packed_varyings.cpp
> index 130b8f6..9aa463c 100644
> --- a/src/compiler/glsl/lower_packed_varyings.cpp
> +++ b/src/compiler/glsl/lower_packed_varyings.cpp
> @@ -273,11 +273,11 @@ lower_packed_varyings_visitor::run(struct gl_shader *shader)
>           continue;
>  
>        /* This lowering pass is only capable of packing floats and ints
> -       * together when their interpolation mode is "flat".  Therefore, to be
> -       * safe, caller should ensure that integral varyings always use flat
> -       * interpolation, even when this is not required by GLSL.
> +       * together when their interpolation mode is "flat".  Treat integers as
> +       * being flat when the interpolation mode is none.
>         */
>        assert(var->data.interpolation == INTERP_QUALIFIER_FLAT ||
> +             var->data.interpolation == INTERP_QUALIFIER_NONE ||
>               !var->type->contains_integer());
>  
>        /* Clone the variable for program resource list before
> @@ -607,7 +607,7 @@ lower_packed_varyings_visitor::get_packed_varying_deref(
>     if (this->packed_varyings[slot] == NULL) {
>        char *packed_name = ralloc_asprintf(this->mem_ctx, "packed:%s", name);
>        const glsl_type *packed_type;
> -      if (unpacked_var->data.interpolation == INTERP_QUALIFIER_FLAT)
> +      if (unpacked_var->is_interpolation_flat())
>           packed_type = glsl_type::ivec4_type;
>        else
>           packed_type = glsl_type::vec4_type;
> @@ -627,7 +627,8 @@ lower_packed_varyings_visitor::get_packed_varying_deref(
>        packed_var->data.centroid = unpacked_var->data.centroid;
>        packed_var->data.sample = unpacked_var->data.sample;
>        packed_var->data.patch = unpacked_var->data.patch;
> -      packed_var->data.interpolation = unpacked_var->data.interpolation;
> +      packed_var->data.interpolation = packed_type == glsl_type::ivec4_type
> +         ? unsigned(INTERP_QUALIFIER_FLAT) : unpacked_var->data.interpolation;
>        packed_var->data.location = location;
>        packed_var->data.precision = unpacked_var->data.precision;
>        packed_var->data.always_active_io = unpacked_var->data.always_active_io;
>