[Mesa-dev] [PATCH V3] glapi: add GL_OES_geometry_shader extension

[Ilia Mirkin]

On Wed, Jan 13, 2016 at 3:55 AM, Tapani Pälli <tapani.palli at intel.com> wrote:
> On 01/13/2016 10:29 AM, Lofstedt, Marta wrote:
>>
>>
>>> -----Original Message-----
>>> From: ibmirkin at gmail.com [mailto:ibmirkin at gmail.com] On Behalf Of Ilia
>>> Mirkin
>>> Sent: Tuesday, January 12, 2016 7:09 PM
>>> To: Marta Lofstedt
>>> Cc: mesa-dev at lists.freedesktop.org; Romanick, Ian D; Lofstedt, Marta
>>> Subject: Re: [PATCH V3] glapi: add GL_OES_geometry_shader extension
>>>
>>> On Tue, Jan 12, 2016 at 9:13 AM, Marta Lofstedt
>>> <marta.lofstedt at linux.intel.com> wrote:
>>>>
>>>> From: Marta Lofstedt <marta.lofstedt at intel.com>
>>>>
>>>> Add xml definitions for the GL_OES_geometry_shader extension and
>>>> expose the extension for OpenGL ES 3.1.
>>>>
>>>> V3: Added dependency to OES_shader_io_blocks and updated to correct
>>>> Khronos extension number.
>>>
>>> May I ask why you did this? OES_shader_io_blocks is a purely shader
>>> compiler/linker feature, I expect it will be enabled whenever GLES 3.1 is
>>> enabled, no? Why would it be tied to geometry shaders? Sure, geometry
>>> shaders require it to work, but just because you have
>>> OES_shader_io_blocks
>>> doesn't necessarily mean you also have geometry shaders...
>>>
>> My intension was to address the co-dependency between oes_geometry_shader
>> and oes_shader_io_block.
>> But as always, you are right Ilia. The dependency issue need to be fixed
>> in the driver.
>>
>> So, please disregard this V3, I will push the V2 with the changes
>> suggested by Ilia in the comments.
>>
>> FYI here are quotes from the oes_geometry_shader specification:
>> " OES_shader_io_blocks or EXT_shader_io_blocks is required."
>
>
> IMO according to this it looks OES_shader_io_blocks is a valid requirement
> as that functionality is not part of OpenGL ES 3.1.

Sure. But that has little bearing on the discussion here --

OES_shader_io_blocks is a compiler feature, not a backend feature. In
order for any backend to expose OES_geometry_shader, the
OES_shader_io_blocks ext needs to be done. But just because it is done
doesn't mean you have geometry shaders.

So you have to make sure that not only does the backend support
geometry shaders, but the core supports OES_shader_io_blocks before
you expose OES_geometry_shader. That doesn't seem too onerous.

  -ilia