[Paraview] calling interactive render

[Joel Howard Willis Weinberger]

I'm trying to write a new render module. I am effectively modifying 
vtkPVCaveRenderModule.* to add in head tracking capabilities. Our head 
tracker works on a polling system so that a handler method gets called on 
a regular basis. Everytime this happens I want it to call 
InteractiveRender() on the module to update the camera position. 
In doing this, I lock the render method using a pthread mutex and exit 
the render call if I am already in the process of calling 
InteractiveRender(). However, when I compile and run Paraview, I get a 
series of bizare errors that occur at seemingly random times (they always 
occur early on but after different numbers of callbacks each time it's 
run). Any idea what these are about (the errors are below)?
--Joel, Brown University

------------------------------------------

X Error of failed request:  BadAccess (attempt to access private resource 
denied)
   Major opcode of failed request:  145 (GLX)
   Minor opcode of failed request:  5 (X_GLXMakeCurrent)
   Serial number of failed request:  6456
   Current serial number in output stream:  6456


ERROR: In 
/users/asf/paraview-1.8/paraview-1.8.5/VTK/Parallel/vtkSocketCommunicator.cxx, 
line 572
vtkSocketCommunicator (0x9cae300): Could not receive tag. 315167


Process id: 0 >> ERROR: In 
/users/asf/paraview-1.8/paraview-1.8.5/VTK/Parallel/vtkMultiProcessController.cxx, 
line 354
vtkSocketController (0x9cae3d0): Could not receive RMI trigger message.

Exit Data Server.

------------------------------------------