gen.py 文件源码

def apply_tropism(turtle, tropism_vector):
    """Apply tropism_vector to turtle direction"""
    h_cross_t = turtle.dir.cross(tropism_vector)
    # calc angle to rotate by (from ABoP) multiply to achieve accurate results from WP attractionUp param
    alpha = 10 * h_cross_t.magnitude
    h_cross_t.normalize()
    # rotate by angle about axis perpendicular to turtle direction and tropism vector
    turtle.dir.rotate(Quaternion(h_cross_t, radians(alpha)))
    turtle.dir.normalize()
    turtle.right.rotate(Quaternion(h_cross_t, radians(alpha)))
    turtle.right.normalize()