[PyOpenGL-Users] bug+fix: multiple Opengl widget repaint causing stack underflow

[Maciej K. <ma...@dg...>]

In PyOpengl 2.0.0.44, Tk/__init__.py, proposed patch:

*** __init__.py.orig    Sun Jul  8 14:26:50 2001
--- __init__.py Mon Dec  3 16:26:26 2001
***************
*** 476,483 ****
--- 476,484 ----
                self.activate()

                glPushMatrix()                  # Protect our matrix
                self.update_idletasks()
+               self.activate()
                w = self.winfo_width()
                h = self.winfo_height()
                glViewport(0, 0, w, h)

If there is more than one Opengl widget, and all of them are exposed
at once (say, when switching desktops), it is quite likely that the
update_idletasks() call is going to result in tkExpose() being called
for one of the other Opengl widgets.  But this means that upon return
from this call the active Opengl widget has changed.  This caused
glPopMatrix() to pop the wrong stack, which every time resulted in
stack underflow, or worse.

-- 
Maciej Kalisiak|mac@] "The real art of conversation is not only to say the
dgp.toronto.edu|www.]  right thing in the right place, but also to leave unsaid
dgp.toronto.edu/~mac]  the wrong thing at the tempting moment."