[Mesa-dev] [PATCH 1/4] glsl: Add simple vector type accessor helpers.

[Kenneth Graunke]

On 06/18/2013 06:47 AM, Ian Romanick wrote:
> On 06/18/2013 04:22 AM, Kenneth Graunke wrote:
>> This patch introduces new functions to quickly grab a pointer to a
>> vector type.  For example:
>>
>>     glsl_type::bvec(4)   returns   glsl_type::bvec4_type
>>     glsl_type::ivec(3)   returns   glsl_type::ivec3_type
>>     glsl_type::uvec(2)   returns   glsl_type::uvec2_type
>>     glsl_type::vec(1)    returns   glsl_type::float_type
>>
>> This is less wordy than glsl_type::get_instance(GLSL_TYPE_BOOL, 4, 1),
>> which can help avoid extra word wrapping.
>
> One thing that's annoying about this code is that we have so many ways
> to get at types.  You can get them from a symbol table, you can get them
> from the direct pointers, you can get them from pointer math, or you can
> get them from get_instance.  I'm not sure replacing one with another
> makes it much better.
>
> I remember considering having separate overloads of get_instance for
> vectors and matrices.  I don't recall why I didn't do it that way.
>
>> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
>> ---
>>   src/glsl/glsl_types.cpp | 52
>> +++++++++++++++++++++++++++++++++++++++++++++++++
>>   src/glsl/glsl_types.h   |  9 +++++++++
>>   2 files changed, 61 insertions(+)
>>
>> diff --git a/src/glsl/glsl_types.cpp b/src/glsl/glsl_types.cpp
>> index df9c5d3..a5491c5 100644
>> --- a/src/glsl/glsl_types.cpp
>> +++ b/src/glsl/glsl_types.cpp
>> @@ -534,6 +534,58 @@ glsl_type::glsl_type(const glsl_type *array,
>> unsigned length) :
>>   }
>>
>>
>> +const glsl_type *const
>> +glsl_type::vec(unsigned components)
>> +{
>> +   if (components == 0 || components > 4)
>> +      return error_type;
>> +
>> +   static const glsl_type *const ts[] = {
>> +      float_type, vec2_type, vec3_type, vec4_type
>> +   };
>> +   return ts[components - 1];
>
> We could just embed this code in get_instance.  That seems better than
> adding new methods that are only used in method that's part of the same
> class.

They're also used in patch 3, outside the class.  That was the 
motivation for adding them...and I thought it was a bit tidier this way.

But if you'd prefer just putting this in get_instance, that's fine by 
me...it's what I originally did in v0 of this series anyway.

--Ken