[Mesa-dev] [PATCH 3/5] main/version: Don't require ARB_compute_shader for OpenGLES 3.1

[Ian Romanick]

On 12/15/2015 05:01 PM, Jordan Justen wrote:
> On 2015-12-15 16:50:39, Ian Romanick wrote:
>> On 12/15/2015 04:08 PM, Jordan Justen wrote:
>>> The OpenGL ARB_compute_shader extension specfication requires at least
>>> 1024 for GL_MAX_COMPUTE_WORK_GROUP_INVOCATIONS, whereas OpenGLES 3.1
>>> only required 128.
>>
>> Does this mean that extensions->ARB_compute_shader is not set?
> 
> Yes. I think we can't set this in some cases due to desktop GL
> requirements, but we should still be able to support CS on ES 3.1.
> 
>> I'm a little bit nervous about that. Are we sure that we check for
>> compute shader support correctly everywhere (i.e., don't just check
>> the extension bit that isn't set)?
> 
> I think we have it pretty well covered. The ES 3.1 CTS seems pretty
> happy with what we have.
> 
> That said, patch 2 was yet another fix to use
> _mesa_has_compute_shaders, and I wouldn't be surprised if we ended up
> finding some more. (I did try to grep to find anything we might have
> missed.)

I just did that too.  I didn't see anything that looked problematic except:

src/mesa/main/get.c:/* HACK: remove when ARB_compute_shader is actually
supported */

This patch is

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

> -Jordan
> 
>>> Signed-off-by: Jordan Justen <jordan.l.justen at intel.com>
>>> Cc: Ian Romanick <idr at freedesktop.org>
>>> Cc: Marta Lofstedt <marta.lofstedt at intel.com>
>>> ---
>>>  src/mesa/main/version.c | 9 ++++++---
>>>  1 file changed, 6 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/src/mesa/main/version.c b/src/mesa/main/version.c
>>> index e92bb11..112a73d 100644
>>> --- a/src/mesa/main/version.c
>>> +++ b/src/mesa/main/version.c
>>> @@ -433,7 +433,8 @@ compute_version_es1(const struct gl_extensions *extensions)
>>>  }
>>>  
>>>  static GLuint
>>> -compute_version_es2(const struct gl_extensions *extensions)
>>> +compute_version_es2(const struct gl_extensions *extensions,
>>> +                    const struct gl_constants *consts)
>>>  {
>>>     /* OpenGL ES 2.0 is derived from OpenGL 2.0 */
>>>     const bool ver_2_0 = (extensions->ARB_texture_cube_map &&
>>> @@ -464,9 +465,11 @@ compute_version_es2(const struct gl_extensions *extensions)
>>>                           extensions->EXT_texture_snorm &&
>>>                           extensions->NV_primitive_restart &&
>>>                           extensions->OES_depth_texture_cube_map);
>>> +   const bool es31_compute_shader =
>>> +      consts->MaxComputeWorkGroupInvocations >= 128;
>>>     const bool ver_3_1 = (ver_3_0 &&
>>>                           extensions->ARB_arrays_of_arrays &&
>>> -                         extensions->ARB_compute_shader &&
>>> +                         es31_compute_shader &&
>>>                           extensions->ARB_draw_indirect &&
>>>                           extensions->ARB_explicit_uniform_location &&
>>>                           extensions->ARB_framebuffer_no_attachments &&
>>> @@ -508,7 +511,7 @@ _mesa_get_version(const struct gl_extensions *extensions,
>>>     case API_OPENGLES:
>>>        return compute_version_es1(extensions);
>>>     case API_OPENGLES2:
>>> -      return compute_version_es2(extensions);
>>> +      return compute_version_es2(extensions, consts);
>>>     }
>>>     return 0;
>>>  }
>>>