[Mesa-dev] [PATCH v2 23/31] glsl: allow bindless samplers/images to be assigned

[Nicolai Hähnle]

On 24.04.2017 12:35, Samuel Pitoiset wrote:
> The ARB_bindless_texture allows sampler and image types to be
> declared as temporary variables, to be converted from/to uvec2
> using explicit constructors, so they can be assigned.
>
> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
> ---
>  src/compiler/glsl/ast_to_hir.cpp | 21 ++++++++++++++++++---
>  1 file changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/src/compiler/glsl/ast_to_hir.cpp b/src/compiler/glsl/ast_to_hir.cpp
> index e4d8bae2f5..8ad6211e2d 100644
> --- a/src/compiler/glsl/ast_to_hir.cpp
> +++ b/src/compiler/glsl/ast_to_hir.cpp
> @@ -940,14 +940,29 @@ do_assignment(exec_list *instructions, struct _mesa_glsl_parse_state *state,
>        lhs_var->data.assigned = true;
>
>     if (!error_emitted) {
> +      bool is_read_only = lhs_var != NULL && (lhs_var->data.read_only ||
> +                          (lhs_var->data.mode == ir_var_shader_storage &&
> +                           lhs_var->data.image_read_only));
> +
> +      if (state->has_bindless()) {
> +         if ((lhs_var->type->is_sampler() || lhs_var->type->is_image()) &&
> +             (lhs_var->data.bindless || lhs_var->data.mode != ir_var_uniform)) {
> +            /* A sampler (or an image) is considered bindless either if it has
> +             * been declared in the default uniform block with the
> +             * bindless_sampler (respectively bindless_image) layout qualifier,
> +             * or when its storage is not uniform because this is not allowed
> +             * without ARB_bindless_texture.
> +             */
> +            is_read_only = false;
> +         }
> +      }

I don't understand why this is necessary. I think the correct approach 
is not to set lhs_var->data.read_only for sampler and image variables.

Cheers,
Nicolai


> +
>        if (non_lvalue_description != NULL) {
>           _mesa_glsl_error(&lhs_loc, state,
>                            "assignment to %s",
>                            non_lvalue_description);
>           error_emitted = true;
> -      } else if (lhs_var != NULL && (lhs_var->data.read_only ||
> -                 (lhs_var->data.mode == ir_var_shader_storage &&
> -                  lhs_var->data.image_read_only))) {
> +      } else if (is_read_only) {
>           /* We can have image_read_only set on both images and buffer variables,
>            * but in the former there is a distinction between assignments to
>            * the variable itself (read_only) and to the memory they point to
>


-- 
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Aber vergiss niemals, wie sie sein sollte.