[Mesa-dev] [PATCH v3 04/32] glsl: make component_slots() returns 2 for samplers/images

[Timothy Arceri]

What happened with my suggestion [1]? Was there a problem?

IMO this patch just hacks around the problem and as mentioned previously 
will result in extra unused uniform storage being allocated.

[1] https://lists.freedesktop.org/archives/mesa-dev/2017-April/153156.html

On 03/05/17 06:53, Samuel Pitoiset wrote:
> Bindless samplers/images are 64-bit unsigned integers, which
> means they consume two components as specified by
> ARB_bindless_texture.
> 
> It looks like we are not wasting uniform storage by changing
> this because default-block uniforms are not packed. So, if
> we use N uint uniforms, they occupy N * 16 bytes in the
> constant buffer. This is something that could be improved.
> 
> Though, count_uniform_size needs to be adjusted to not count
> a sampler (or image) twice.
> 
> As a side effect, this will probably break the cache if you
> have one because it will consider sampler/image types as
> two components.
> 
> v3: - update the comments
> 
> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
> ---
>   src/compiler/glsl/link_uniforms.cpp | 8 ++++++--
>   src/compiler/glsl_types.cpp         | 2 ++
>   2 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/src/compiler/glsl/link_uniforms.cpp b/src/compiler/glsl/link_uniforms.cpp
> index f1e0885fbd..0a199dbbd6 100644
> --- a/src/compiler/glsl/link_uniforms.cpp
> +++ b/src/compiler/glsl/link_uniforms.cpp
> @@ -340,9 +340,13 @@ private:
>         if (type->contains_subroutine()) {
>            this->num_shader_subroutines += values;
>         } else if (type->contains_sampler()) {
> -         this->num_shader_samplers += values;
> +         /* Samplers (bound or bindless) are counted as two components as
> +          * specified by ARB_bindless_texture. */
> +         this->num_shader_samplers += values / 2;
>         } else if (type->contains_image()) {
> -         this->num_shader_images += values;
> +         /* Images (bound or bindless) are counted as two components as
> +          * specified by ARB_bindless_texture. */
> +         this->num_shader_images += values / 2;
>   
>            /* As drivers are likely to represent image uniforms as
>             * scalar indices, count them against the limit of uniform
> diff --git a/src/compiler/glsl_types.cpp b/src/compiler/glsl_types.cpp
> index bf078ad614..89f611d0cb 100644
> --- a/src/compiler/glsl_types.cpp
> +++ b/src/compiler/glsl_types.cpp
> @@ -1293,6 +1293,8 @@ glsl_type::component_slots() const
>   
>      case GLSL_TYPE_SAMPLER:
>      case GLSL_TYPE_IMAGE:
> +      return 2;
> +
>      case GLSL_TYPE_SUBROUTINE:
>         return 1;
>   
>