Unavoidably dark colors in polygons?

I am programming a driving simulator for a psychology experiment, and have a GL_QUADS square drawn to act as a target area for the subject. I am trying to change the color of this polygon, but no matter what color I use I get a nearly black color. On my friend’s computer, the only color change that shows is pure green, which actually shows up as a brownish green.

I’ve tried to add ambient lighting to brighten the color, to no avail. Does anyone know why colors on a polygon would always turn out so dark, or how to specify a brighter color? I’ve used several forms of glColor3D at the beginning of my polygon definition, with the same result for each (even changing the alpha value seems to have no effect).

If anyone can help I’m indebted for life… thanks,

Make sure you disable texturing when rendering your polygon. Chances are the dark color you are seeing is a dark area on a texture you’ve loaded.

This assumes that you have textures loaded somewhere in your program. But if you are not using textures, then this may not be the solution to your problem. cheers!

Lighting could also be the culprit.

Disable lighting for that polygon. Then re-enable after.