[Mesa-dev] [PATCH v2 04/31] glsl: make component_slots() returns 2 for samplers/images

[Timothy Arceri]

On 24/04/17 20:35, 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.
> 
> 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 b462cb9d59..3331c85af4 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;
> +         /* Old-style (or bound) samplers 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;
> +         /* Old-style (or bound) images are counted as two components as
> +          * specified by ARB_bindless_texture. */

*/ should go on the following line.

I think I would rather see 862361c4f547efb reverted and image support 
added. You are missing some of the uses with this change, and it just 
seems cleaner to keep the counting separate to begin with.

> +         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 0480bef80e..df148cfd21 100644
> --- a/src/compiler/glsl_types.cpp
> +++ b/src/compiler/glsl_types.cpp
> @@ -1298,6 +1298,8 @@ glsl_type::component_slots() const
>   
>      case GLSL_TYPE_SAMPLER:
>      case GLSL_TYPE_IMAGE:
> +      return 2;
> +
>      case GLSL_TYPE_SUBROUTINE:
>         return 1;
>   
>