无法绘制IFS分形树枝

Question

当前，我正在尝试绘制一个symmetric binary tree  通过IFS（迭代功能系统），但结果始终只是 branch tips。

我无法弄清楚自己做错了什么或缺少了什么。

这是IFS：here

这是我的代码：

RenderWindow window(VideoMode(480, 640), "fractals everywhere");
CircleShape point(1);
int chance;
float x, y, w, h, nx, ny, px, py;

void SymmetricBinaryTrees()
{
    float r = 0.57f;
    float o = 0.785f;

    chance = rand() % 3;

    switch (chance)
    {
    case 0:
        nx = r * cos(o) * x + (-1 * r * sin(o) * y);
        ny = r * sin(o) * x + r * cos(o) * y + 1;
        break;
    case 1:
        nx = r * cos(o) * x + r * sin(o) * y;
        ny = -1 * r * sin(o) * x + r * cos(o) * y + 1;
        break;
    case 2:
        nx = x;
        ny = y;
        break;
    }
}

void nextPoint()
{
    SymmetricBinaryTrees();

    x = nx; y = ny;
}

void drawPoint()
{
    px = _map(x, -1.078, 1.078f, 0, w); py = _map(y, 0.f, 2.078f, h, 0); // maps the position accordingly
    point.setPosition(px, py);

    window.draw(point);
}

int main()
{
    srand(time(NULL));

    w = window.getSize().x * 1.f;
    h = window.getSize().y * 1.f;

    x = 0.f; y = 0.f;

    window.setFramerateLimit(60);

    while (window.isOpen())
    {
        Event e;

        while (window.pollEvent(e))
            if (e.type == Event::Closed) window.close();

        for (int i = 1; i <= 500; i++)
        {
            drawPoint();
            nextPoint();
        }

        window.display();
    }
    return 0;
}

This是我用于代码的网站。

如果有人可以帮助我或有任何想法，我将非常感谢，谢谢。