rotation.py 文件源码

def rotation_from_up_and_look(up, look):
    '''
    Rotation matrix to rotate a mesh into a canonical reference frame. The
    result is a rotation matrix that will make up along +y and look along +z
    (i.e. facing towards a default opengl camera).

    Note that if you're reorienting a mesh, you can use its `reorient` method
    to accomplish this.

    up: The foot-to-head direction.
    look: The direction the eyes are facing, or the heel-to-toe direction.

    '''
    up, look = np.array(up, dtype=np.float64), np.array(look, dtype=np.float64)
    if np.linalg.norm(up) == 0:
        raise ValueError("Singular up")
    if np.linalg.norm(look) == 0:
        raise ValueError("Singular look")
    y = up / np.linalg.norm(up)
    z = look - np.dot(look, y)*y
    if np.linalg.norm(z) == 0:
        raise ValueError("up and look are colinear")
    z = z / np.linalg.norm(z)
    x = np.cross(y, z)
    return np.array([x, y, z])