i just noticed that outlines does not work very well when zoomed out to the maximum. they overlap the shape of the font rendering it unreadable. the problem can be solved if the outline is half transparent. change glColor3f(1-r, 1-g, 1-b); in line 35 and 61 to glColor4f(1-r, 1-g, 1-b, .5); it seems to be working now. any comments are welcome. gabor