[Mesa-dev] [PATCH v2 08/28] glsl: Uniform linking support for doubles

[Ilia Mirkin]

On Fri, Feb 6, 2015 at 2:38 AM, Ian Romanick <idr at freedesktop.org> wrote:
> On 02/06/2015 06:56 AM, Ilia Mirkin wrote:
>> From: Dave Airlie <airlied at gmail.com>
>>
>> Signed-off-by: Dave Airlie <airlied at redhat.com>
>> ---
>>  src/glsl/link_uniforms.cpp | 7 ++++++-
>>  1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/glsl/link_uniforms.cpp b/src/glsl/link_uniforms.cpp
>> index de2f6c9..0a4dac2 100644
>> --- a/src/glsl/link_uniforms.cpp
>> +++ b/src/glsl/link_uniforms.cpp
>> @@ -51,6 +51,9 @@ values_for_type(const glsl_type *type)
>>        return 1;
>>     } else if (type->is_array() && type->fields.array->is_sampler()) {
>>        return type->array_size();
>> +   } else if ((type->is_array() && type->fields.array->is_double()) ||
>> +              type->is_double()) {
>> +      return 2 * type->component_slots();
>>     } else {
>>        return type->component_slots();
>>     }
>> @@ -608,7 +611,9 @@ private:
>>        }
>>
>>        if (type->without_array()->is_matrix()) {
>> -         this->uniforms[id].matrix_stride = 16;
>> +            unsigned N = type->base_type == GLSL_TYPE_DOUBLE ? 8 : 4;
>> +            unsigned items = row_major ? type->matrix_columns : type->vector_elements;
>> +            this->uniforms[id].matrix_stride = glsl_align(items * N, 16);
>
> Could we add an assert that matrix_stride is either 16 or 32?  The
> value is always 16 if GLSL_TYPE_FLOAT or items <= 2, and it's 32
> otherwise.  I'm on the fence whether it's better to just do that
> explicitly:
>
>     const unsigned items = row_major ? type->matrix_columns : type->vector_elements;
>     this->uniforms[id].matrix_stride = (type->base_type == GLSL_TYPE_FLOAT || items <= 2) ? 16 : 32;
>
> Thoughts?

I actually kinda prefer

assert(items <= 4)

Since N is fixed at either 4 or 8, and glsl_align is a pretty obvious
function. I've added this for the next version.