Polygon geometry - any suggestions?

[Colin Holgate]

Don't know if this would work out for you, but you can have a simple  
image that you check the color of pixels to tell where you are. I used  
that method in this thing I did:

http://staff.funnygarbage.com/colin/track/track.mov

The stack is here:

http://staff.funnygarbage.com/colin/track.rev.zip

Once we did a golf game, where you had to hit the ball onto various  
greens (using perspective 3D), and by checking the color of the pixel  
you landed on it was possible to know whether you were on a green, and  
on which one, even if the areas were broken up into multiple strange  
shaped blobs.