I'm looking for a quick and easy way to tell if a vector or invisible model is within the camera viewpoint. That way I can start an action only when it is not visible from the camera view.

Can this be done without having to compare the model's and camera's x/y coordinates and thier distance to each other, and then comparing that with the camera's angle and taking into account the camera's arc? That just seems overly complicated. Or maybe there's a good algorithm that takes all this into account in just a few lines. Any ideas?

if (vec_to_screen(model.x,camera))
0 - Result is outside the view.
1 - Result is inside the view.

Thanks for the help, I've got it worked out.