Thanks for the reply. I have reviewed the function myself and I must admit it didn't really work well. But that doesn't mean the function is wrong ;)
I noticed they didn't normalize the aimvec and I assume the fldot calculation is in radians?
So if i want to extract the angle from all this I would have to add something like:
new anglemode:mode = radians;
float angle = floatacos(fldot,mode)
and then compare the different angles?
I could make the check first (fldot > 0.5) to make sure the player we're trying to find IS in the viewcone. However I think it was stated somewhere else that ViewCone didn't really work well?