Wierd artifacts on smoothed models

For some time now I’m trying to get a pretty good looking piece of source as a start for my new game’s GL engine.

After some changes I’m suddenly having trouble with smoothed surfaces; as if the normals are in error.

This is what it looks like now, this should have been a nice sword:

It is as if the normals are wrong, but after some testing it must have something to do with the lighting. (because with lighting off all is ok)

The black parts change while the model rotates, they change as if they are black in only a few fixed angles from the cam.

I’ve only used a normal position light.

If anyone can help me; I’d be verry pleased, It’s been bugging me for about 4 days now and I can’t seem to get it fixed…

Thanks

PS: It’s not the model; even when I use the default GLUT or GLU models, I’m having the same trouble.

[This message has been edited by Clairvoyant (edited 08-25-2002).]

It is as if the normals are wrong, but after some testing it must have something to do with the lighting. (because with lighting off all is ok)

Well… normals really only affect the display of your model when lighting is enabled. So just because it looks ok with lighting off doesn’t mean your normals aren’t messed up.

Another things to check might be that you enabled depth testing and clear the depth buffer when you clear the screen.