__init__.py 文件源码

def extend(p0, p1, p2, loopa, verts):
    # will extend this with a tri centered at p0
    #print('extend')
    #print(p0,p1,p2,[verts[i] for i in loopa])

    # both difference point upward, we extend to the second
    d1 = p1 - p0
    d2 = p0 - p2
    p = (verts[loopa[0]] + verts[loopa[1]] + verts[loopa[2]] + verts[loopa[3]]) / 4
    a = d1.angle(d2, 0)
    if abs(a) < 0.05:
        #print('small angle')
        loopb = vertcopy(loopa, verts, p0 - d2 / 2 - p)
        # all verts in loopb are displaced the same amount so no need to find the minimum distance
        n = 4
        return ([(loopa[(i) % n], loopa[(i + 1) % n], loopb[(i + 1) % n], loopb[(i) % n]) for i in range(n)], loopa, loopb)

    r = d2.cross(d1)
    q = Quaternion(r, -a)
    dverts = [verts[i] - p for i in loopa]
    #print('large angle',dverts,'axis',r)
    for dv in dverts:
        dv.rotate(q)
    #print('rotated',dverts)
    for dv in dverts:
        dv += (p0 - d2 / 2)
    #print('moved',dverts)
    loopb = vertextend(verts, dverts)
    # none of the verts in loopb are rotated so no need to find the minimum distance
    n = 4
    return ([(loopa[(i) % n], loopa[(i + 1) % n], loopb[(i + 1) % n], loopb[(i) % n]) for i in range(n)], loopa, loopb)