[Mesa-dev] [PATCH 1/4] gallium: add new pipe_screen::legal_resource_size() function

[Brian Paul]

On 09/17/2012 08:12 AM, Brian Paul wrote:
> On 09/17/2012 04:16 AM, Jose Fonseca wrote:
>>
>>
>> ----- Original Message -----
>>> From: Brian Paul<brianp at vmware.com>
>>>
>>> To implement proxy textures. If a gallium driver doesn't implement
>>> this function we'll just continue to use the core Mesa fallback code.
>>>
>>> Without this hook we really have no good way to implement OpenGL
>>> proxy
>>> textures with gallium drivers.
>>
>> Brian,
>>
>> This interface seems a good thing to add. A just have a few
>> suggestion/remarks below.
>>
>>> ---
>>> src/gallium/include/pipe/p_screen.h | 8 ++++++++
>>> 1 files changed, 8 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/src/gallium/include/pipe/p_screen.h
>>> b/src/gallium/include/pipe/p_screen.h
>>> index fdf6fa2..718a72b 100644
>>> --- a/src/gallium/include/pipe/p_screen.h
>>> +++ b/src/gallium/include/pipe/p_screen.h
>>> @@ -138,6 +138,14 @@ struct pipe_screen {
>>> enum pipe_video_profile
>>> profile );
>>>
>>> /**
>>> + * Check the size of the resource/texture given by 'res'.
>>> + * Used to implement proxy textures.
>>> + * \return TRUE if size is OK, FALSE if too large.
>>> + */
>>> + boolean (*legal_resource_size)(struct pipe_screen *screen,
>>
>> I think the name would benefit from a verb somewhere in it, e.g.,
>> is_resource_size_legal.
>>
>> I suspect this function will check more than size (e.g., number of
>> samples, format). If so, then I'd suggest a more generic name, such
>> as, "can_create_resource".
>>
>> Also, shouldn't this interface return an enum (e.g., pipe_error), so
>> that one can distinguish between "can't create a texture because not
>> enough memory now", vs "can't create this texture ever because of HW
>> limitations", or is such distinction useless for GL proxy textures?

Oops, I missed this part.  We could certainly return a pipe error to 
give more info, but at the OpenGL level it won't matter.  I'd say 
let's keep it as a boolean for now until we find a reason that more 
info is needed.

-Brian