Hi everybody.

I have a working QGLWidget which inserts colored cones according to mouse click, and shows part of them by depth-comparison, like in the image at the link below:
http://upload.wikimedia.org/wikipedi...noi_2D.svg.png

The boundaries where the colors change represent points with the same depth. I've spent now many days searching and trying via OpenGL coding, using stencil and depth buffers, but I'm not managing to get into a result like in the image at the link below:
http://mathworld.wolfram.com/images/...iagram_700.gif

i.e., a white image with only the boundaries filled with black.

I found this tutorial: http://igortrindade.wordpress.com/20...l-and-shaders/
which now makes me wonder if there's a very simple way to achieve the result I want only using some basic QGL properties.

Thank you once again, masters.