[Mesa-dev] [PATCH 1/7] softpipe: Move the faces array from view to filter_args

[Krzesimir Nowak]

On Fri, Sep 11, 2015 at 11:57 PM, Emil Velikov <emil.l.velikov at gmail.com>
wrote:

> On 11 September 2015 at 19:07, Krzesimir Nowak <krzesimir at kinvolk.io>
> wrote:
> > With that, sp_sampler_view instances are not abused anymore as a local
> > storage, so we can later make them constant.
> > ---
> >  src/gallium/drivers/softpipe/sp_tex_sample.c | 36
> +++++++++++++++++-----------
> >  src/gallium/drivers/softpipe/sp_tex_sample.h |  4 +---
> >  2 files changed, 23 insertions(+), 17 deletions(-)
> >
> > diff --git a/src/gallium/drivers/softpipe/sp_tex_sample.c
> b/src/gallium/drivers/softpipe/sp_tex_sample.c
> > index 489cae7..d5a7ed6 100644
> > --- a/src/gallium/drivers/softpipe/sp_tex_sample.c
> > +++ b/src/gallium/drivers/softpipe/sp_tex_sample.c
>
> > @@ -3594,11 +3596,16 @@ sp_tgsi_get_samples(struct tgsi_sampler
> *tgsi_sampler,
> >        float cs[TGSI_QUAD_SIZE];
> >        float ct[TGSI_QUAD_SIZE];
> >        float cp[TGSI_QUAD_SIZE];
> > +      float faces[TGSI_QUAD_SIZE];
> >
> > -      convert_cube(sp_sview, sp_samp, s, t, p, c0, cs, ct, cp);
> > +      convert_cube(sp_sview, sp_samp, s, t, p, c0, cs, ct, cp, faces);
> >
> > +      filt_args.faces = faces;
> If I remember it correctly the contents of faces will become invalid
> and as we exit the function, thus any attempt to use them (via
> filt_args.faces) and things will go crazy.
>

And that's fine - filt_args variable itself goes out of scope when you exit
the function. And we do not store the pointer to faces anywhere for later
reuse or anything.


>
> >        sample_mip(sp_sview, sp_samp, cs, ct, cp, c0, lod, &filt_args,
> rgba);
> >     } else {
> > +      static const float zero_faces[TGSI_QUAD_SIZE] = {0.0f, 0.0f,
> 0.0f, 0.0f};
> > +
> > +      filt_args.faces = zero_faces;
> Here we should be safe due to the static qualifier.
>
> >        sample_mip(sp_sview, sp_samp, s, t, p, c0, lod, &filt_args, rgba);
> >     }
> >  }
>
> > diff --git a/src/gallium/drivers/softpipe/sp_tex_sample.h
> b/src/gallium/drivers/softpipe/sp_tex_sample.h
> > index 72b4a1a..6743b7e 100644
> > --- a/src/gallium/drivers/softpipe/sp_tex_sample.h
> > +++ b/src/gallium/drivers/softpipe/sp_tex_sample.h
> > @@ -72,6 +72,7 @@ typedef void (*img_filter_func)(struct sp_sampler_view
> *sp_sview,
> >  struct filter_args {
> >     enum tgsi_sampler_control control;
> >     const int8_t *offset;
> > +   const float *faces;
> Afaict during calculation of face (in convert_cube) uint type is used.
> Won't this cause unnecessary int <> float conversions ?
>
>
Good point, I haven't noticed that.


> Cheers,
> Emil
>
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