- // acos returns a value between zero and PI, which means we don't know which
- // quadrant the angle is in... Though, if the y-coordinate of the vector is
- // negative, that means that the angle is in quadrants III - IV.
+ // acos returns a value between zero and TAU/2, which means we don't know
+ // which quadrant the angle is in... However, if the y-coordinate of the
+ // vector is negative, that means that the angle is in quadrants III - IV.