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

[Ilia Mirkin]

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)

  -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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>
>
>
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