[Mesa-dev] [PATCH 3/4] st/mesa: Add support for ARB_post_depth_coverage

[Ilia Mirkin]

On Tue, May 23, 2017 at 3:19 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> On Tue, May 23, 2017 at 3:00 PM, Lyude <lyude at redhat.com> wrote:
>> Signed-off-by: Lyude <lyude at redhat.com>
>> ---
>>  src/mesa/state_tracker/st_extensions.c     | 1 +
>>  src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 6 +++++-
>>  2 files changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
>> index f3db702..7674156 100644
>> --- a/src/mesa/state_tracker/st_extensions.c
>> +++ b/src/mesa/state_tracker/st_extensions.c
>> @@ -600,6 +600,7 @@ void st_init_extensions(struct pipe_screen *screen,
>>        { o(ARB_occlusion_query2),             PIPE_CAP_OCCLUSION_QUERY                  },
>>        { o(ARB_pipeline_statistics_query),    PIPE_CAP_QUERY_PIPELINE_STATISTICS        },
>>        { o(ARB_point_sprite),                 PIPE_CAP_POINT_SPRITE                     },
>> +      { o(ARB_post_depth_coverage),          PIPE_CAP_POST_DEPTH_COVERAGE              },
>>        { o(ARB_query_buffer_object),          PIPE_CAP_QUERY_BUFFER_OBJECT              },
>>        { o(ARB_robust_buffer_access_behavior), PIPE_CAP_ROBUST_BUFFER_ACCESS_BEHAVIOR   },
>>        { o(ARB_sample_shading),               PIPE_CAP_SAMPLE_SHADING                   },
>> diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
>> index 76cd4dc..e038206 100644
>> --- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
>> +++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
>> @@ -6376,9 +6376,13 @@ st_translate_program(
>>     }
>>
>>     if (procType == PIPE_SHADER_FRAGMENT) {
>> -      if (program->shader->Program->info.fs.early_fragment_tests)
>> +      if (program->shader->Program->info.fs.early_fragment_tests) {
>>           ureg_property(ureg, TGSI_PROPERTY_FS_EARLY_DEPTH_STENCIL, 1);
>>
>> +         if (program->shader->Program->info.fs.post_depth_coverage)
>> +            ureg_property(ureg, TGSI_PROPERTY_FS_POST_DEPTH_COVERAGE, 1);
>
> From the spec,
>
> "Use of this feature implicitly enables early fragment tests."
>
> However I see nothing that would force early_fragment_tests to be
> enabled when post_depth_coverage is enabled.

A decision point here, btw, is whether this is up to the frontend or
the backend. My thought is that it's up to the frontend to flip both
on rather than the backend to know that early frag tests are a || b ||
c || d || ... .