vector_shortcuts.py 文件源码

def signed_angle(v1, v2, look):
    '''
    Compute the signed angle between two vectors.

    Returns a number between -180 and 180. A positive number indicates a
    clockwise sweep from v1 to v2. A negative number is counterclockwise.

    '''
    # The sign of (A x B) dot look gives the sign of the angle.
    # > 0 means clockwise, < 0 is counterclockwise.
    sign = np.sign(np.cross(v1, v2).dot(look))

    # 0 means collinear: 0 or 180. Let's call that clockwise.
    if sign == 0:
        sign = 1

    return sign * angle(v1, v2, look)