[vtkusers] Offscreen Rendering with Xvfb

[Joey Mukherjee]

Ok, I am trying to use the vtkOffscreenRenderWindow by John Shalf with Xvfb, but 
am running into a core dump.  What is happening is this line:

v = glXChooseVisual(this->DisplayId,
                    DefaultScreen(this->DisplayId),attributeList);
                    
is returning NULL.  This cause the v->depth to core.

Why would glXChooseVisual return NULL?  

This is how I am starting Xvfb:

Xvfb :1 -pixdepths 8 16 32 -screen 0 1600x1200x16

I've also tried it without the pixdepths argument, but no luck.

Any ideas?

Thanks,
Joey

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+     Joey Mukherjee                 "The price of freedom is eternal      +
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