[Mesa-dev] [PATCH v2 1/4] nir: set default lod to texture opcodes that needed it but don't provide it

[Lionel Landwerlin]

On 10/10/17 14:35, Samuel Iglesias Gonsálvez wrote:
> Signed-off-by: Samuel Iglesias Gonsálvez <siglesias at igalia.com>
> ---
>   src/compiler/nir/nir_lower_tex.c | 68 ++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 68 insertions(+)
>
> diff --git a/src/compiler/nir/nir_lower_tex.c b/src/compiler/nir/nir_lower_tex.c
> index 65681decb1c..d3380710405 100644
> --- a/src/compiler/nir/nir_lower_tex.c
> +++ b/src/compiler/nir/nir_lower_tex.c
> @@ -717,6 +717,52 @@ linearize_srgb_result(nir_builder *b, nir_tex_instr *tex)
>                                     result->parent_instr);
>   }
>   
> +static void
> +set_default_lod(nir_builder *b, nir_tex_instr *tex)
> +{
> +   b->cursor = nir_before_instr(&tex->instr);
> +
> +   /* We are going to emit the same texture but adding a default LOD.
> +    */
> +   int num_srcs = tex->num_srcs + 1;
> +   nir_tex_instr *new = nir_tex_instr_create(b->shader, num_srcs);
> +
> +   new->op = tex->op;
> +   new->sampler_dim = tex->sampler_dim;
> +   new->texture_index = tex->texture_index;
> +   new->dest_type = tex->dest_type;
> +   new->is_array = tex->is_array;
> +   new->is_shadow = tex->is_shadow;
> +   new->is_new_style_shadow = tex->is_new_style_shadow;
> +   new->sampler_index = tex->sampler_index;
> +   new->texture = nir_deref_var_clone(tex->texture, new);
> +   new->sampler = nir_deref_var_clone(tex->sampler, new);
> +   new->coord_components = tex->coord_components;

There are a couple of fields you're not copying : component & 
texture_array_size
Not 100% sure whether they need to be.

> +
> +   nir_ssa_dest_init(&new->instr, &new->dest, 4, 32, NULL);
> +
> +   int src_num = 0;
> +   for (int i = 0; i < tex->num_srcs; i++) {
> +      nir_src_copy(&new->src[src_num].src, &tex->src[i].src, new);
> +      new->src[src_num].src_type = tex->src[i].src_type;
> +      src_num++;
> +   }
> +
> +   new->src[src_num].src = nir_src_for_ssa(nir_imm_int(b, 0));
> +   new->src[src_num].src_type = nir_tex_src_lod;

I think you could get rid of the src_num variable and just use 
(new->num_srcs - 1) to set the default lod src.

> +   src_num++;
> +
> +   assert(src_num == num_srcs);
> +
> +   nir_ssa_dest_init(&new->instr, &new->dest,
> +                     tex->dest.ssa.num_components, 32, NULL);
> +   nir_builder_instr_insert(b, &new->instr);
> +
> +   nir_ssa_def_rewrite_uses(&tex->dest.ssa, nir_src_for_ssa(&new->dest.ssa));
> +
> +   nir_instr_remove(&tex->instr);
> +}
> +
>   static bool
>   nir_lower_tex_block(nir_block *block, nir_builder *b,
>                       const nir_lower_tex_options *options)
> @@ -813,6 +859,28 @@ nir_lower_tex_block(nir_block *block, nir_builder *b,
>            progress = true;
>            continue;
>         }
> +
> +      /* TXF, TXS and TXL require a LOD but not everything we implement using those
> +       * three opcodes provides one.  Provide a default LOD of 0.
> +       */
> +      if (tex->op == nir_texop_txf || tex->op == nir_texop_txs ||
> +          tex->op == nir_texop_txl || tex->op == nir_texop_query_levels ||
> +          (tex->op == nir_texop_tex && b->shader->stage != MESA_SHADER_FRAGMENT)) {
> +         int i;
> +         bool has_lod = false;
> +         for (i = 0; i < tex->num_srcs; i++) {
> +            if (tex->src[i].src_type == nir_tex_src_lod) {
> +               has_lod = true;
> +               break;
> +            }
> +         }
> +
> +         if (!has_lod) {
> +            set_default_lod(b, tex);
> +            progress = true;
> +            continue;
> +         }
> +      }
>      }
>   
>      return progress;