I'm working on a "tower defense" style game for a class project and I can't seem to figure out how to detect collision within a radius around a tower. I cannot simply use the boundingrect function as the area to detect collision goes beyond the actual boundingrect of the object. I tried to re-implement the shape function to create a path, but that causes the program to crash when a tower is clicked.

Can anyone give some insight on how I would create an "imaginary" circle around an object and check for collisions?