I am currently developing a game and have a question regarding dragging sprites. I am fairly confident with how to use the touch events to drag a sprite according to the touch x,y coordinates, however I need to be able to constrain the possible motion of the sprite to a fixed path. More specifically I am looking to implement game mechanics in which the user can drag a sprite, but only in a circular motion (like turning a wheel). Is anyone aware of how I might implement this? Thanks for any information you can provide.