[GtkGLExt] Rendering multiple vtk actors on a mac.

[Valere R Coffman <valerie coffman nist gov>]

Hi,

I'm using pygtkglext with vtk.  I'm having a problem rendering multiple vtk
actors on a mac.  I only have the problem when using gtkglext to put vtk stuff
in a gtk window -- I don't have the problem when I just use a regular vtk render
window without gtk and gtkglext.

My python code renders an image volume using FixedPointVolumeRayCastMapper and
another actor which is from the CubeSource, mapped with the PolyDataMapper.  On
the linux system I'm using (xorg version 7.1.0-16) this works fine.  However, on
a mac (xfree version 4.3), when the cube is added, the image volume disappears.
 When the cube is removed, the image comes back.  When I run remotely on the
linux system while displaying on a mac, I also have the disappearing image. 
When running remotely on the mac and displaying on linux, I don't have the
disappearing image problem.  This leads me to believe that there is some strange
interaction between vtk and/or gtkglext and the X server on the mac. 

Has anybody had any experience with this?  Any ideas?

Thanks,
Valerie