misc fixes for VC4

[Rob Clark]

On Fri, Jan 2, 2015 at 4:27 PM, Keith Packard <keithp at keithp.com> wrote:
> "Jasper St. Pierre" <jstpierre at mecheye.net> writes:
>
>> On a UMA system, that's effectively free. With a triangle fan and
>> glMultiDrawElements, you can get it down to four, same as a quad. Though
>> I'm not sure if mesa fully supports glMultiDrawElements.
>>
>> I believe mesa supports primitive reset, so with a triangle fan and
>> primitive reset, you can get it down to five indices per quad.
>
> The only interesting question is what hardware that doesn't do quads
> wants; offering an alternative path is fine, we just need to make it
> actually useful :-)
>

well, adreno doesn't do native quads, and I think vc4 doesn't
either... so an alternative path is useful.  Perhaps we should cook up
an extension to indicate that quads are emulated if just avoiding
quads across the board is not a good option for some hw...

BR,
-R



> --
> -keith