triquad.py 文件源码

def Angle(a, b, c, points):
    """Return Angle abc in degrees, in range [0,180),
    where a,b,c are indices into points."""

    u = Sub2(points.pos[c], points.pos[b])
    v = Sub2(points.pos[a], points.pos[b])
    n1 = Length2(u)
    n2 = Length2(v)
    if n1 == 0.0 or n2 == 0.0:
        return 0.0
    else:
        costheta = Dot2(u, v) / (n1 * n2)
        if costheta > 1.0:
            costheta = 1.0
        if costheta < - 1.0:
            costheta = - 1.0
        return math.acos(costheta) * 180.0 / math.pi