if dragging is happening or not
Detects if the interactor is being dragged and returns dragVector if that happens. Detection algorithm: if the distance between the interaction point and the origin position exceeds the dragging threshold, then dragging is happening.
position that is used to compute the drag vector
the dragVector as a vec3 if dragging and null otherwise
Manages the logic for the dragging behaviour, especially detects when dragging happens, and provides the associated dragVector