public static float angularDistance (float a1, float a2) {
        float ma1 = mirrorAngle(a1), ma2 = mirrorAngle(a2);
        return Math.min(Math.abs(a1 - a2), Math.abs(ma1 - ma2));
    }
public static float angularDistance ( float a1 , float a2 ) { float ma1 = mirrorAngle ( a1 ) , ma2 = mirrorAngle ( a2 ) ; return Math . min ( Math . abs ( a1 - a2 ) , Math . abs ( ma1 - ma2 ) ) ; }
Returns the (shortest) distance between two angles, assuming that both angles are in
[-pi, +pi].