[Mesa-dev] [Freedreno] [PATCH 1/2] nir: allow texture offsets with cube maps

[Jason Ekstrand]

On Mon, Nov 20, 2017 at 3:11 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:

> On Mon, Nov 20, 2017 at 5:16 PM, Jason Ekstrand <jason at jlekstrand.net>
> wrote:
> > On Sun, Nov 19, 2017 at 11:54 AM, Ilia Mirkin <imirkin at alum.mit.edu>
> wrote:
> >>
> >> GL doesn't have this, but some hardware supports it. This is convenient
> >> for lowering tg4 to plain texture calls, which is necessary on Adreno
> >> A4xx hardware.
> >>
> >> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
> >> ---
> >>  src/compiler/nir/nir.h | 15 +++++++++++++--
> >>  1 file changed, 13 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
> >> index f46f6147110..64965ae16d6 100644
> >> --- a/src/compiler/nir/nir.h
> >> +++ b/src/compiler/nir/nir.h
> >> @@ -1364,8 +1364,7 @@ nir_tex_instr_src_size(const nir_tex_instr *instr,
> >> unsigned src)
> >>     if (instr->src[src].src_type == nir_tex_src_ms_mcs)
> >>        return 4;
> >>
> >> -   if (instr->src[src].src_type == nir_tex_src_offset ||
> >> -       instr->src[src].src_type == nir_tex_src_ddx ||
> >> +   if (instr->src[src].src_type == nir_tex_src_ddx ||
> >>         instr->src[src].src_type == nir_tex_src_ddy) {
> >>        if (instr->is_array)
> >>           return instr->coord_components - 1;
> >> @@ -1373,6 +1372,18 @@ nir_tex_instr_src_size(const nir_tex_instr
> *instr,
> >> unsigned src)
> >>           return instr->coord_components;
> >>     }
> >>
> >> +   /* Usual APIs don't allow cube + offset, but we allow it, with 2
> >> coords for
> >> +    * the offset, since a cube maps to a single face.
> >> +    */
> >> +   if (instr->src[src].src_type == nir_tex_src_offset) {
> >> +      unsigned ret = instr->coord_components;
> >> +      if (instr->is_array)
> >> +         ret--;
> >> +      if (instr->sampler_dim == GLSL_SAMPLER_DIM_CUBE)
> >> +         ret--;
> >> +      return ret;
> >
> >
> > I think I'd rather this look more like the one above:
> >
> > if (instr->is_array)
> >    return instr->coord_components;
> > else if (instr->sampler_dim == GLSL_SAMPLER_DIM_CUBE)
> >    return 2;
> > else
> >    return instr->coord_components - 1;
> >
> > It seems a bit cleaner and/or more explicit to me.
>
> OK. Although your version is slightly wrong, but I get the idea. Will
> do that in a v2. (array should get -1, and cube should always get 2
> even if it's an array)
>

I'd forgotten about cube arrays, yes, those would naturally be -2.  In that
case, maybe -- for each subtraction is a good idea...


>   -ilia
>
> >
> > Also, bonus points to anyone who converts this function to use a switch.
> :-P
> >
> > --Jason
> >
> >>
> >> +   }
> >> +
> >>     return 1;
> >>  }
> >>
> >> --
> >> 2.13.6
> >>
> >> _______________________________________________
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> >> mesa-dev at lists.freedesktop.org
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> >
> >
> >
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> >
>
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