[PyOpenGL-Users] A puzzle regarding running PyOpenGL interactively

[Perry G. <pe...@st...>]

We have had problems with PyOpenGL for more recent releases
of Redhat (e.g., 6.x,7.x, 8.x) that manifest themselves in odd ways.
This is the simplest illustration of something that works for
some OpenGL implementations and not others.

If you start an interactive Python session and types the following
sequence of commmands:

>>> import OpenGL
>>> from OpenGL.GL import *
>>> from OpenGL.Tk import *
>>> o=Opengl()

>>> Exception in Tkinter callback
Traceback 
[...]
AttributeError: 'Opengl' instance has no attribute 'redraw'
[window turns pink]

>>> glClearColor(1,0,0,0)
>>> glClear(GL_COLOR_BUFFER_BIT)

On some installations, this results in a Tk window appearing, and
the last command changes the background color to red.
On other installstions, nothing happens with the last command.
(Nor does the window turn pink on o=Opengl()).
The above will not work for the default installations of OpenGL
for Redhat 8 for example (The SGI library apparently).

[A natural question is why anyone would run OpenGL in this manner.
We use OpenGL to generate plot windows from an interactive
command line for a scientific command-line-oriented analysis
environment. We do not use it in the usual way of generating
a standalone GUI application. The above test illustrates the
installations for which the plotting windows are nonfunctional
or not]

Does anyone understand what it is that causes PyOpenGL to stop
working with Python's interactive mode?

When we use Mesa instead on Redhat, it works. Unfortunately some
users have NVIDIA cards that require the NVIDIA OpenGL library
which does not work.

We would like to understand what the fundamental problem is and 
whether there is any solution.

Thanks, Perry Greenfield