Games101作业4

1.recursive_bezier用以实现De Casteljau算法

cv::Point2f recursive_bezier(const std::vector<cv::Point2f> &control_points, float t) 
{
    // TODO: Implement de Casteljau's algorithm
    //return cv::Point2f();
    if (control_points.size() < 2)
    {
        return control_points[0];
    }
    std::vector<cv::Point2f> temp_control_points = {};
    for (int i = 0; i < control_points.size() - 1; i++)
    {
        cv::Point2f temp_point = (1 - t) * control_points[i] + t * control_points[i + 1];
        temp_control_points.push_back(temp_point);
    }
    return recursive_bezier(temp_control_points, t);  

}

2.bezier调用recursive_bezier函数，指定每次计算目标点坐标时使用的t值。

bezier每次传入的t都会返回一个在对应t下贝塞尔曲线上的点。

void bezier(const std::vector<cv::Point2f> &control_points, cv::Mat &window) 
{
    // TODO: Iterate through all t = 0 to t = 1 with small steps, and call de Casteljau's 
    // recursive Bezier algorithm.
    for (double t = 0.0; t <= 1.0; t += 0.001)
    {
        cv::Point2f point = recursive_bezier(control_points, t);
        window.at<cv::Vec3b>(point.y, point.x)[1] = 255;
    }

3.修改点的数量

修改点的数量只需要修改mouse_handler里的点的数量的限制和main函数点的数量

void mouse_handler(int event, int x, int y, int flags, void *userdata) 
{
    if (event == cv::EVENT_LBUTTONDOWN && control_points.size() < 5) 
    {
        std::cout << "Left button of the mouse is clicked - position (" << x << ", "
        << y << ")" << '\n';
        control_points.emplace_back(x, y);
    }    

}


if (control_points.size() == 5) 
        {
            naive_bezier(control_points, window);
             bezier(control_points, window);

            cv::imshow("Bezier Curve", window);
            cv::imwrite("my_bezier_curve.png", window);
            key = cv::waitKey(0);

            return 0;
        }

结果