message: Open3D/showpointcloud: Documentation
  Added point cloud information for cpp example of showing point cloud.
diff: # showPointCloud example
  ### Overview
  +
  This example demonstrates how to capture data from the TOF system, build a point cloud from it and display it.
  +#### Creating and showing the point cloud
  +
  +* Initilize the system and adiToF camera;
  +* Get the camera intrinsic parameters;
  +* Enable noise reduction;
  +* Create and initialize open3D visualizer:
  +```console
  +visualization::Visualizer pointcloud_vis;
  +pointcloud_vis.CreateVisualizerWindow("Pointcloud", 800, 800);
  +bool is_geometry_added_pointcloud = false;
  +```
  +* Initialize *camera::PinholeCameraIntrinsic* with the intrisic parameters:
  +```console
  +camera::PinholeCameraIntrinsic intrinsicParameters(frameWidth, frameHeight,
  + fx, fy, cx, cy);
  +```
  +* Request frame from adiToF camera;
  +* Transform the depth image into Open3D *geometry::Image* type;
  +* Transform the IR image into Open3D *geometry::Image* type;
  +* Transform the 16bits depth image (the depth image raw) into Open3D *geometry::Image* type;
  +* Color the depth *geometry::Image* with a rainbow spectrum;
  +* Combine IR *geometry::Image* and the depth *geometry::Image* to get the color *geometry::Image*;
  +* Create *geometry::RGBDImage* from depth and color images:
  +```console
  +auto rgbd_ptr = geometry::RGBDImage::CreateFromColorAndDepth(color_image, depth16bits_image, 1000.0, 3.0, false);
  +```
  +* Create the point cloud from the *geometry::RGBDImage* using the intrisic parameters:
  +```console
  +pointcloud_ptr = geometry::PointCloud::CreateFromRGBDImage(*rgbd_ptr, intrinsicParameters);
  +```
  +* Show in the visualizer the point cloud created:
  +```console
  +if (!is_geometry_added_pointcloud) {
  + pointcloud_vis.AddGeometry(pointcloud_ptr);
  + is_geometry_added_pointcloud = true;
  + }
  +pointcloud_vis.UpdateGeometry();
  +is_window_closed = pointcloud_vis.PollEvents();
  +pointcloud_vis.UpdateRender();
  +```
  +#### Point cloud example
  ![Display Image](/doc/img/pointcloud_cpp.png)
  +
  