[vtk-developers] OpenGL Extension loading with OSMesa?

[Utkarsh Ayachit]

I've pushed a patch to gerrit that ensures that OSMesaGetProcAddress()
gets used by the vtkOpenGLExtensionManager when built with OSMesa
(without X).

http://review.source.kitware.com/#/t/2632/

Thoughts?

Utkarsh

On Tue, Apr 16, 2013 at 12:28 PM, Cyrus Harrison <cyrush at llnl.gov> wrote:
> Thanks Burlen!
>
> This was how I read things, but I wanted to make sure I was not missing
> something.
>
> We are looking into this as well for VisIt, b/c we need to be able to use
> extensions in both the X11 and Mesa case.
> Our goal is to work with an off-the-shelf VTK build (even if it doesn't
> include mesa support) and I think we are on the right path to do so.
>
> For this issue, my initial conclusion was if we could register functions in
> the vtkgl:: namespace we could bootstrap a workable solution.
> However functions in this namespace did not appear to be exported.
>
> Long term, it would be great if there was a path for both the X11 and Mesa
> logic in vtkOpenGLExtensionManager. That rules out some compile time
> choices. We are fine with a pure runtime solution, but I don't think that
> meets the needs of all VTK users.
>
>
> -Cyrus
>
>
> On 04/16/13 09:26, burlen wrote:
>>
>> Hi Kathleen,
>>
>> I need this functionality and am starting to work on it, it won't be ready
>> for vtk 6. I'm curious to see if anyone else is already working on it.
>> Please speak up if so.
>>
>> I'm just digging in but my understanding is that VTK provides it's own
>> extension wrangler (Utilities/ParseOGLExt) for compile time creation of
>> headers (vtkgl.h), and an extension manager vtkOpenGLExtensionManager for
>> run time api to check the results. However, in the cmake code there is logic
>> such that when X11 is disabled or not present, the extension
>> wrangler/pareser is not run. Also like the previous post mentioned the
>> parser is not aware of OSMesaGetProcAddress, thus at run time the extension
>> manager knows nothing about the extensions os mesa provides. So currently
>> OSMesa without X11 means no extensions are available.
>>
>> Burlen
>>
>> On 04/15/2013 02:32 PM, Kathleen S. Biagas wrote:
>>>
>>> Just wanted to ping the list again, see if anyone has an answer to
>>> Cyrus' question?
>>>
>>> Kathleen
>>>
>>> On Tue, 2013-03-05 at 14:07 -0800, Cyrus Harrison wrote:
>>>>
>>>> Hi Everyone,
>>>>
>>>> I have been hunting for quite a bit with no luck - so I am hoping the
>>>> experts can give me a ruling here:
>>>>
>>>> Looking at VTK-6 source from git, I was expecting to find
>>>> `OSMesaGetProcAddress' wired into the guts of VTK somewhere to support
>>>> OpenGL extensions for the OSMesa case.
>>>>
>>>> Does that logic exist or does OSMesa simply result in a configuration
>>>> that defines "VTK_NO_EXTENSION_LOADING"?
>>>>
>>>>
>>>> Thanks for your help,
>>>> -Cyrus
>>>>
>>>>
>>>>
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