[PATCH v3 5/5] wined3d: Create a null vertex binding and attributes for unbound shader inputs.

[Henri Verbeet]

On Tue, 20 Apr 2021 at 15:08, Jan Sikorski <jsikorski at codeweavers.com> wrote:
> @@ -2071,6 +2072,46 @@ static bool wined3d_context_vk_update_graphics_pipeline_key(struct wined3d_conte
>              }
>          }
>
> +        if (attribute_count < signature->element_count)
> +        {
I don't think that check is safe. Specifically, there may be multiple
input signature elements for the same input register. (E.g., mapping
v0.xy to "COLOUR0", and v0.zw to "COLOUR1".)

> +                for (i = 0; i < signature->element_count; ++i)
> +                {
> +                    struct wined3d_shader_signature_element *element = &signature->elements[i];
> +                    uint32_t location = element->register_idx;
> +                    VkVertexInputAttributeDescription *a;
> +
> +                    if ((stream_info.use_map & (1 << location)))
> +                        continue;
> +
> +                    a = &key->attributes[attribute_count++];
> +                    a->location = location;
> +                    a->binding = null_binding;
> +                    a->format = VK_FORMAT_R32G32B32A32_UINT;
> +                    a->offset = 0;
> +                }
Similarly, this may end up creating multiple attribute descriptions
for the same input location if we don't keep track of which ones we've
already processed here. We should probably skip elements with
"sysval_semantic" set, although I wouldn't expect anything bad to
happen if we don't.

Somewhat similar to my comment to patch 4/5, we could alternatively
use the "shader->reg_maps.input_registers" bitmap by doing something
like "uint32_t map = vs->reg_maps.input_registers &
~stream_info.use_map;", and then iterating over that map.