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

[Ian Romanick]

On 01/12/2016 10:09 AM, Ilia Mirkin wrote:
> 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...

I was going to say the same thing.

Since OES_shader_io_blocks is largely a software feature, I expect at
some point it will be enabled by default in all drivers that support
GLES 3.1.  The same is unlikely to be true of geometry shaders.

> In practical terms, there's a non-trivial chance that A4xx will get
> tessellation before geometry shaders, which would also require
> OES_shader_io_blocks to be exposed.
> 
>   -ilia