[PyOpenGL-Users] bug on glcanvas?

[altern <al...@gm...>]

hi all

I am having a strange error with the corrdinate system with a glcanvas 
on Linux (but not on windows!). I have a complex system for 2D opengl 
rendering and it is proving to be really difficult to fix this. So I 
decided to do a simple example to see where the problem was. The simple 
example does work fine both on linux and windows now. So once this is 
working I thought it should be pretty easy to find out the point that 
causes the error in the complex code, but I cannot really find which is 
the different bit. So I was wondering if this error sounds familiar to 
anyone in the list. I am writing both to wxPython-users and 
pyOpenGL-users lists.

This is the detailed description of error:
I use  glOrtho(0, 800,  600, 0, 5000, 0)
to set up the projection, this means that if I set a vertex like this
glVertex2i(400, 300)
this should be in the center of the canvas (0,0 is top left of the 
window). Moreover, if I increase the y value, this should move the 
vertex to the bottom of the window
This is true in windows but under Linux I get the (0,0) on the center of 
the screen and if I increase the y value of a vertex it moves up instead 
of down. On top of this the values of the opengl are not mapped to 
pixels and moving a vertex by 1 unit (should move 1 pixel) moves it out 
of the window.

If anyone ever had a similar problem it would be great to hear some hints.

Thanks

enrike