[Mesa-dev] [PATCH] glsl: set matrix_stride for non matrices with atomic counter buffers

[Ilia Mirkin]

On Fri, Nov 13, 2015 at 10:53 AM, Tapani Pälli <tapani.palli at intel.com> wrote:
> On 11/12/2015 05:47 PM, Ilia Mirkin wrote:
>>
>> On Mon, Nov 2, 2015 at 6:36 AM, Tapani Pälli <tapani.palli at intel.com>
>> wrote:
>>>
>>> Patch sets matrix_stride as 0 for non matrix uniforms that are in a
>>> atomic counter buffer. Matrix stride calculation for actual matrix
>>> uniforms is done during link_assign_uniform_locations.
>>>
>>>  From ARB_program_interface_query specification:
>>>
>>> GL_MATRIX_STRIDE:
>>>
>>>     "For active variables not declared as a matrix or array of matrices,
>>>     zero is written to <params>.  For active variables not backed by a
>>>     buffer object, -1 is written to <params>, regardless of the variable
>>>     type."
>>>
>>> Signed-off-by: Tapani Pälli <tapani.palli at intel.com>
>>> ---
>>>   src/glsl/link_atomics.cpp | 2 ++
>>>   1 file changed, 2 insertions(+)
>>>
>>> diff --git a/src/glsl/link_atomics.cpp b/src/glsl/link_atomics.cpp
>>> index cdcc06d..3aa52db 100644
>>> --- a/src/glsl/link_atomics.cpp
>>> +++ b/src/glsl/link_atomics.cpp
>>> @@ -240,6 +240,8 @@ link_assign_atomic_counter_resources(struct
>>> gl_context *ctx,
>>>            storage->offset = var->data.atomic.offset;
>>>            storage->array_stride = (var->type->is_array() ?
>>>
>>> var->type->without_array()->atomic_size() : 0);
>>> +         if (!var->type->is_matrix())
>>> +            storage->matrix_stride = 0;
>>
>> Can atomics ever be in matrices?
>
>
> Nope, but one can query matrix stride property of a uniform that is 'backed
> by' atomic counter buffer.

Right, I get that... but why the if (!var->type->is_matrix())?