多维转一维的方法

//生成彩图的值
        char imgpath[256];

        int* cube = new int[500 * 500 * 500 * 3];

        for (int s = 0; s < 500; s++)
        {
            sprintf_s(imgpath, "D:\\cubeimg\\%d.png", s + 2150);
            Mat img = imread(imgpath);
            if (!img.data)
            {
                cout << "载入失败" << endl;
            }
            Mat img_resize;
            resize(img, img_resize, Size(1000, 500), 0, 0, CV_INTER_LINEAR);
            Mat submat(500, 500, CV_8UC3);
            img_resize.colRange(499, 999).copyTo(submat);

            for (int i = 0; i < 500; i++)
            {
                for (int j = 0; j < 500; j++)
                {
                    {
                        int t = submat.at<Vec3b>(i, j)[ch];
                    //四维转换为一维的方法，三维的可以
                    //int index = 500 * 500 s + 500 * i + j;
                    //一维转三维可以用除运算，和模运算的方法
                        int index = 500 * 500 * 3 * s + 500 * 3 * i + 3 * j + ch;
                        cube[index] = t;
                    }
                }
            }
        }

        FILE *fp;

        if ((fp = fopen("d:\\image.pixel", "wb")) == 0)

        {
            printf("open failed!");

            exit(1);
        }

        fwrite(cube, sizeof(int), 500 * 500 * 500 * 3, fp);
        fclose(fp);