Technical: Depth buffer in OpenGL

I just thought I’d post this up here, in case other people had the same problem.

The Megastrata project started out like any other first-time project: cobbled together from examples found on the internet. One of the long-standing traditions regarding development involve the so-called “hack-n-slash” technique: smash the code around until it works.

Megastrata started life out as the NoiseViewer, which was, true to its name, simply a 2D noise patter viewer. Hence, there was originally no need for a depth buffer.

When the leap was made to 3D, I made it work on Windows. But the OS X version didn’t render the same way. Wolfgang put a lot of effort into debugging it, and after sending screenshots back and forth, we understood that the problem was with the depth buffer.

I saw something suspicious when I looked up the OpenGL FAQ on the subject. Step one reads:

1. Ask for a depth buffer when you create your window.

Evidently, Windows automatically specifies a depth buffer created when initializing the window, whereas OS X does not do this by default.

We changed the line in the code that read:

glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);



and the problem was solved.

Posted on October 12, 2009 at 11:54 pm by eli · Permalink
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