OpenCV随机数与随机颜色绘制

Mat bg = Mat::zeros(Size(512,512), CV_8UC3);
  int w = bg.cols;
  int h = bg.rows;
  RNG rng(12345);
  while (true)
  {
    int c = cv::waitKey(10);
    if (c == 27) {
      break;
    }
    int x1 = rng.uniform(0, w);
    int y1 = rng.uniform(0, h);
    int x2 = rng.uniform(0, w);
    int y2 = rng.uniform(0, h);
    bg = Scalar(0, 0, 0);
    line(bg, Point(x1, y1), Point(x2, y2), Scalar(rng.uniform(0,255), rng.uniform(0, 255), rng.uniform(0, 255)), 2, LINE_AA, 0);
    imshow("Draw_random", bg);
  }