[Mesa-dev] [PATCH 6/9] glsl: mark named uniform block arrays as active if defined with shared or std140 layout qualifier

[Samuel Iglesias Gonsálvez]

On 05/05/15 01:03, Matt Turner wrote:
> On Tue, Feb 24, 2015 at 10:02 AM, Eduardo Lima Mitev <elima at igalia.com> wrote:
>> From: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
>>
>> If the named uniform block is an array declared with a shared or
>> std140 layout qualifier and no shader instruction has referenced it,
>> then it is never marked as active, then num_array_elements is zero.
>>
>> Section 2.12.6 (Uniform Variables) of the OpenGL ES 3.0.4 spec says
>> that is should be considered active:
>>
>>  "All members of a named uniform block declared with a shared or
>>   std140 layout qualifier are considered active, even if they are not
>>   referenced in any shader in the program. The uniform block itself is
>>   also considered active, even if no member of the block is
>>   referenced."
>>
>> Fixes:
>>
>> dEQP-GLES3.functional.ubo.random.basic_instance_arrays.18
>>
>> Signed-off-by: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
>> ---
>>  src/glsl/link_uniform_blocks.cpp | 26 ++++++++++++++++++++++++++
>>  1 file changed, 26 insertions(+)
>>
>> diff --git a/src/glsl/link_uniform_blocks.cpp b/src/glsl/link_uniform_blocks.cpp
>> index f5fc502..67a3f00 100644
>> --- a/src/glsl/link_uniform_blocks.cpp
>> +++ b/src/glsl/link_uniform_blocks.cpp
>> @@ -213,6 +213,32 @@ link_uniform_blocks(void *mem_ctx,
>>        const glsl_type *const block_type =
>>           b->type->is_array() ? b->type->fields.array : b->type;
>>
>> +      /* Section 2.12.6 (Uniform Variables) of the OpenGL ES 3.0.4 spec says:
>> +       *
>> +       *   "All members of a named uniform block declared with a shared or
>> +       *   std140 layout qualifier are considered active, even if they are not
>> +       *   referenced in any shader in the program. The uniform block itself is
>> +       *   also considered active, even if no member of the block is
>> +       *   referenced."
>> +       *
>> +       * If the named uniform block is an array declared with a shared or
>> +       * std140 layout qualifier and no shader instruction has referenced it,
>> +       * then it is never marked as active, then num_array_elements is zero.
>> +       */
> 
> As far as I can tell, this is a difference between Desktop GL and ES.
> If that is indeed the case, shouldn't the block below contain a
> _mesa_is_gles3() check?
> 

Yeah, you are right, the block below should have _mesa_is_gles3() check.

There is an unreviewed patch from Antía [0] which tackles the same bug
but in src/glsl/link_uniform_block_active_visitor.cpp.
It also needs the _mesa_is_gles3() check. However, I think her patch is
better than this one.

Can you take a look at it? If you agree, we can skip this patch.

Sam

[0] http://lists.freedesktop.org/archives/mesa-dev/2015-March/079102.html

>> +      if (b->num_array_elements == 0 && b->type->is_array() &&
>> +          (b->type->interface_packing == GLSL_INTERFACE_PACKING_STD140 ||
>> +           b->type->interface_packing == GLSL_INTERFACE_PACKING_SHARED)) {
>> +         struct link_uniform_block_active *const block =
>> +            (struct link_uniform_block_active *) entry->data;
>> +         block->num_array_elements = block->type->length;
>> +         block->array_elements = reralloc(mem_ctx,
>> +                                          block->array_elements,
>> +                                          unsigned,
>> +                                          block->num_array_elements);
>> +         /* Mark the entire array as used. */
>> +         for (unsigned i = 0; i < block->num_array_elements; i++)
>> +            block->array_elements[i] = i;
>> +      }
>>        assert((b->num_array_elements > 0) == b->type->is_array());
>>
>>        block_size.num_active_uniforms = 0;
>> --
>> 2.1.3
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