[Mesa-dev] [PATCH 5/8] mesa: expose AMD_texture_texture4

[Marek Olšák]

On Wed, Aug 15, 2018 at 3:10 PM Ian Romanick <idr at freedesktop.org> wrote:
>
> On 08/08/2018 07:12 PM, Marek Olšák wrote:
> > From: Marek Olšák <marek.olsak at amd.com>
> >
> > because the closed driver exposes it.
>
> Aside from AMD_texture_texture4 being really, really under-specified,
> there is one big difference between the two extensions.
>
>     7)  Can both texture *AND* texture4 built-in functions
>     sample from the same sampler in a shader?
>
>     No.
>
> vs.
>
>     (5) Can both texture *AND* textureGather built-in functions
>         sample from the same sampler in a shader?
>
>        RESOLVED: Yes.
>
> Of course, the AMD_texture_texture4 spec doesn't say what "no" means.
> Compile error?  Garbage results?  A kitten dies?  Zero guidance from the
> spec.  We should imitate whatever the closed driver does... unless a
> kitten dies.  Don't do that.

The closed driver handles it exactly the same as ARB_texture_gather,
which is functionally equivalent to this patch. There is no compile error.

Marek