[Mesa-dev] [PATCH v2 1/3] glsl: add glsl_external_mode() helper

[Timothy Arceri]

On 17/05/18 14:36, Marek Olšák wrote:
> On Wed, May 16, 2018 at 11:01 PM, Timothy Arceri <tarceri at itsqueeze.com 
> <mailto:tarceri at itsqueeze.com>> wrote:
> 
> 
> 
>     On 17/05/18 10:59, Marek Olšák wrote:
> 
>         On Sat, May 12, 2018 at 12:49 AM, Timothy Arceri
>         <tarceri at itsqueeze.com <mailto:tarceri at itsqueeze.com>
>         <mailto:tarceri at itsqueeze.com <mailto:tarceri at itsqueeze.com>>>
>         wrote:
> 
>              This allows us to get the variable mode as specified by the
>         GLSL
>              spec. We will use this in the following patch.
>              ---
>                src/compiler/glsl/ast_to_hir.cpp | 73
>         ++++++++++++++++++++++++++++++++
>                1 file changed, 73 insertions(+)
> 
>              diff --git a/src/compiler/glsl/ast_to_hir.cpp
>              b/src/compiler/glsl/ast_to_hir.cpp
>              index 3bf581571e2..a7a9ac80769 100644
>              --- a/src/compiler/glsl/ast_to_hir.cpp
>              +++ b/src/compiler/glsl/ast_to_hir.cpp
>              @@ -4175,6 +4175,79 @@
>         apply_type_qualifier_to_variable(const struct
>              ast_type_qualifier *qual,
>                   apply_image_qualifier_to_variable(qual, var, state, loc);
>                }
> 
>              +/**
>              + * Get the GLSL mode specified in for system values (if any).
>              + */
>              +static enum ir_variable_mode
>              +glsl_external_mode(enum ir_variable_mode internal_mode,
>              gl_shader_stage stage,
>              +                   unsigned slot) {
>              +   if (internal_mode == ir_var_system_value) {
>              +      switch (slot) {
>              +      case SYSTEM_VALUE_SUBGROUP_SIZE:
>              +         return ir_var_uniform;
>              +      case SYSTEM_VALUE_PRIMITIVE_ID:
>              +         if (stage == MESA_SHADER_GEOMETRY) {
>              +            return ir_var_shader_out;
> 
> 
>         System values are always inputs. This one is gl_PrimitiveIDIn.
> 
>              +         } else {
>              +            return ir_var_shader_in;
>              +         }
>              +      case SYSTEM_VALUE_TESS_LEVEL_OUTER:
>              +      case SYSTEM_VALUE_TESS_LEVEL_INNER:
>              +         if (stage == MESA_SHADER_TESS_CTRL) {
>              +            return ir_var_shader_out;
> 
> 
>         System values are always inputs, i.e. TESS_CTRL isn't allowed here.
> 
> 
>     Hmm yeah your right I seem to have confused myself here a bit.
>     However SYSTEM_VALUE_SUBGROUP_SIZE seems to be the odd one out in
>     that its a uniform.
> 
> 
> Why is it uniform?

 From ARB_shader_ballot:


     (Add to the list of built-in uniform variable declaration)

         uniform uint  gl_SubGroupSizeARB;

> 
> Marek