[vtk-developers] OpenGL Extension loading with OSMesa?

[Burlen Loring]

On 4/17/2013 11:52 AM, Kevin H. Hobbs wrote:
> On 04/17/2013 01:58 PM, burlen wrote:
>> Hi Kevin,
>>
>> Tests that make use of classes that require extensions pass silently
>> when the extensions aren't present, thus the fact that the dashboard is
>> green doesn't mean a whole lot in this case. With Utkarsh's patch the
>> extension manager is now correctly loading the extension string and
>> appending supported versions. However, tests for specific open gl
>> versions are hardwired to fail when software rendering is used. Take a
>> close look vtkOpenGLExtensionManager::ExtensionSupported implementation.
>>
>> Version tests are used ubiquitously in VTK for example take a look at
>> vtkTextureObject::IsSupported implementation. In Mesa 9.1.1 all of the
>> required extensions needed by the texture object are available, however
>> it's not working because the version test fails.
>>
>> Hope that clarifies things
> I do not believe the situation was unclear.
>
> All threads should have such clear explanation of what's going on
> somewhere in them so, thank you for the clarification.
>
> I ran the dashboards because the gerrit robot builds do not use
> OSMesa. After all of the Dashboard greening efforts I'd hate to
> see an OSMesa patch get merged without a build on the dashboard
> that actually used OSMesa.
>
> All it took was a few seconds to check out the patch and edit a
> copy of my nightly cmake script.
>
> Also, it was a lot of fun to see the LoadOpenGLExtension  test
> get more and more output.
>
>
it will be interesting to see the dashboards now that some of the 
extension dependent code will run. I wouldn't be surprised to see some 
failures. The surface LIC doesn't run correctly, for one thing there's a 
bug in Mesa 9.1.1 where GL_ARB_texture_float isn't built when requested. 
After patching so that it's built I'm finding other issues with the 
shaders and render to texture, the result textures are empty/clear.