[Mesa-dev] [PATCH 4/5] i965: Enable the ARB_transform_feedback3 extension on Gen7+.

[Ian Romanick]

On 10/28/2013 10:57 AM, Kenneth Graunke wrote:
> On 10/28/2013 10:50 AM, Ian Romanick wrote:
>> On 10/26/2013 01:33 PM, Kenneth Graunke wrote:
>>> This extension is written a bit strangely.  Although it introduces the
>>> concept of multiple transform feedback streams, it doesn't actually
>>> provide more than a single stream.
>>>
>>> The ARB_gpu_shader5 extension is what introduces the ability to write to
>>> streams other than stream #0 and increases the required number of streams.
>>>
>>> Since we don't yet support ARB_gpu_shader5, we can safely enable
>>> ARB_transform_feedback3 even though we only support a single stream.
>>> This does provide some useful functionality: applications can now use
>>> more than one interleaved transform feedback buffer.
>>>
>>> I believe this extension can be enabled independently from
>>> ARB_transform_feedback2, so I've enabled it universally on Gen7+.
>>
>> I think that's technically true, but I also think this will make our
>> implementation unjustly unique.  That's sure to uncover app bugs that I
>> don't think we want to chase.  I think I'd feel more comfortable only
>> enabling 3 when 2 is also enabled.
> 
> Agreed.  I'll change it to enable all three together or nothing.

Then add my R-b. :)

> Thanks, Ian.
> 
> --Ken