[Mesa-dev] [PATCH 4/6] mesa/st: wire up DiscardSubFramebuffer

[Rob Clark]

On Tue, Dec 11, 2018 at 6:10 PM Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>
> On Tue, Dec 11, 2018 at 5:50 PM Rob Clark <robdclark at gmail.com> wrote:
> >
> > Signed-off-by: Rob Clark <robdclark at gmail.com>
> > ---
> >  src/gallium/include/pipe/p_context.h | 11 +++++++++++
> >  src/mesa/state_tracker/st_cb_fbo.c   | 26 ++++++++++++++++++++++++++
> >  2 files changed, 37 insertions(+)
> >
> > diff --git a/src/gallium/include/pipe/p_context.h b/src/gallium/include/pipe/p_context.h
> > index d4e9179b78a..eb52c7e9a4e 100644
> > --- a/src/gallium/include/pipe/p_context.h
> > +++ b/src/gallium/include/pipe/p_context.h
> > @@ -811,6 +811,17 @@ struct pipe_context {
> >     void (*invalidate_surface)(struct pipe_context *ctx,
> >                                struct pipe_surface *surf);
> >
> > +   /**
> > +    * Invalidate a portion of a surface.  This is used to
> > +    *
> > +    * (1) implement glInvalidateSubFramebuffer() and friends
> > +    * (2) as a hint before a scissored clear (which is turned into draw_vbo()
> > +    *     that the cleared rect can be discarded
> > +    */
> > +   void (*invalidate_sub_surface)(struct pipe_context *ctx,
> > +                                  struct pipe_surface *surf,
> > +                                  const struct pipe_scissor_state *rect);
>
> I think pipe_box is a bit more natural here than scissor state? box is
> used for transfers, etc. This could also enable you to to specify a
> sub-3d area. And perhaps by passing a level, you could go back to this
> being a resource (and just extend invalidate_resource)?

I prefer surface to resource+params, as I mentioned in the other reply
on this thread.

I guess box is an option.. it is overkill for what the gl API wants
and I can't immediately think of a use for this for more than a 2d
slice of a higher dimensioned object, where pipe_surface is a perfect
fit.  (Are there any GPUs that can render to a 3d render target?  I
guess at least the intersection of tilers and GPUs that can is pretty
small for now..)

BR,
-R

>
>   -ilia