For a prototype that needs an action associated with scrolling or dragging, there's probably no easier tool than Principle. The concept of "drivers" is basically like a traditional keyframe timeline, although instead of time, the dimension is scroll distance. So, you can keyframe behaviors tied to scrolling very easily. It takes a matter of seconds to set up a complex parallax scroll behavior. To achieve direction lock, we'll nest scrolling groups rather than applying both scroll directions to one group.