fog

Hello,
I’m trying to make a large fishtank, and I want to use fog to simulate water.
But because my fishtank doesn’t use the hall scene I would like to make an area where fog is used(a cubic like area).
How can I do that?
Thanx Hylke

Or is this not possible?

of course it is possible.

some pointers about the EXT_fog_coord to fiddle with fog values per vertex :
lesson 41 :
http://nehe.gamedev.net/lesson.asp?index=09

http://www.apgsoftware.co.uk/gl/demos.html

Thanx.
But the first one about fog coordinates doesn’t work.
I get a brown/orange window, and that’s it.
I’m pretty shoure my 3d card supports it.
I have the latest nvidia driver and my card is geforce fx.
What could be wrong?
Hylke