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

[Samuel Pitoiset]

On 05/05/2017 02:18 AM, Timothy Arceri wrote:
> 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.

Can we just move on and fix the extra unused uniform storage later?
> 
> [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;
>>