why do colors change in fullscreen mode?

OpenGL OpenGL: Basic Coding
1

Hi people, seems like when ever I use fullscreen mode, the colors of the drawing change to a different shade. This happens when I use game mode, and also happens when I run NeHe’s tutorial examples in full screen mode. And it happens on several computers already.

WHY???

Thanks!

2

You are either
a)using a Voodoo 1/2 or some other card that doesn’t offer windowed OpenGL acceleration, so your windowed output is the software rasterizer in action
b)switching from/to an inappriate color depth. 256 color modes are likely to cause problems, switch to at least 16bit color depth (64k colors).