OpenCV Viz Camera Movement

#include <opencv2/opencv.hpp>
#include <opencv2/viz.hpp>

#include <iostream>
#include <fstream>
#include <string>

using namespace std;
using namespace cv;

bool bCamView = false;


void keyboard_callback(const viz::KeyboardEvent &event, void* cookie)
{
    if (event.action == 0 && !event.symbol.compare("s"))
        bCamView = !bCamView;
}

int _tmain(int argc, _TCHAR* argv[])
{
    /// Create 3D windows
    viz::Viz3d Window_3D("Estimation Coordinate Frame");
    Window_3D.setBackgroundColor(); // black by default
    Window_3D.registerKeyboardCallback(&keyboard_callback);

    // Create the pointcloud
    cout << "Reading the 3D points  ... ";

    const int NoOfCamera = 10;
    const double    fx = 1239.911,
                    fy = 1239.911,
                    cx = 519.909,
                    cy = 246.656;

    Matx33d K = Matx33d(fx, 0, cx,
                        0, fy, cy,
                        0, 0, 1);

    vector<Affine3d> Cam_Trajectory;
    Mat RotationVector(1, 3, CV_64FC1, Scalar(0.0));
    Mat TranslationVector(3, 1, CV_64FC1, Scalar(1.0));
    for (size_t i = 0; i < NoOfCamera; ++i)
    {
        Cam_Trajectory.push_back(Affine3d(RotationVector, TranslationVector));
        TranslationVector.at<double>(2, 0) += 1.0;
    }

    Vec3d Pt3d_Object(0.10,0.10,15.0);
    /// Wait for key 'q' to close the window
    cout << endl << "Press:                       " << endl;
    cout << " 's' to switch the camera view" << endl;
    cout << " 'q' to close the windows    " << endl;


    if (Cam_Trajectory.size() > 0)
    {
        // animated trajectory
        int idx = 0, forw = -1, n = static_cast<int>(Cam_Trajectory.size());

        while (!Window_3D.wasStopped())
        {
            /// Render a 3D cube
            Affine3d point_pose(Mat::eye(3, 3, CV_64F), Pt3d_Object);
            viz::WCube cube_widget(Point3f(0.1, 0.1, 0.0), Point3f(0.0, 0.0, -0.1), true, viz::Color::blue());
            cube_widget.setRenderingProperty(viz::LINE_WIDTH, 2.0);
            Window_3D.showWidget("Cube1", cube_widget, point_pose);

            Affine3d cam_pose = Cam_Trajectory[idx];

            viz::WCameraPosition cpw(0.25); // Coordinate axes
            viz::WCameraPosition cpw_frustum(K, 0.3, viz::Color::yellow()); // Camera frustum
            if (bCamView)
            {
                Window_3D.setViewerPose(cam_pose);
            }
            else
            {
                // render complete trajectory
                Window_3D.showWidget("cameras_frames_and_lines_est", viz::WTrajectory(Cam_Trajectory, viz::WTrajectory::PATH, 1.0, viz::Color::green()));

                Window_3D.showWidget("CPW", cpw, cam_pose);
                Window_3D.showWidget("CPW_FRUSTUM", cpw_frustum, cam_pose);
            }

            // update trajectory index (spring effect)
            forw *= (idx == n || idx == 0) ? -1 : 1;
            idx += forw;

            // frame rate 1s
            Window_3D.spinOnce(100, true);
            Window_3D.removeAllWidgets();

        }

    }
    Window_3D.close();
    return 0;
}