I'm trying to come up with a good conversion formula to go from one definition of angles in a circle to another.
In the origin system, zero is up, 90 is right, 180 is down, 270 is left.
In the target system, zero is right, -90 is down, +/- 180 is left, 90 is up.
Going backwards is easy: y=(-x+90)%360. Can anyone figure out how to go forwards in a single equation?