The CloudViewer

The CloudViewer is a straight forward, simple point cloud visualization, meant to get you up and viewing clouds in as little code as possible.

Note

The CloudViewer class is NOT meant to be used in multi-threaded applications! Please check the documentation on PCLVisualizer or read the PCLVisualizer tutorial for thread safe visualization.

Simple Cloud Visualization

If you just want to visualize something in your app with a few lines of code, use a snippet like the following one:

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 #include <pcl/visualization/cloud_viewer.h>
 //...
 void
 foo ()
 {
   pcl::PointCloud<pcl::PointXYZRGB>::Ptr cloud;
   //... populate cloud
   pcl::visualization::CloudViewer viewer ("Simple Cloud Viewer");
   viewer.showCloud (cloud);
   while (!viewer.wasStopped ())
   {
   }
 }

A more complete sample:

The following shows how to run code on the visualization thread. The PCLVisualizer is the back end of the CloudViewer, but its running in its own thread. To access it you must use callback functions, to avoid the visualization concurrency issues. However care must be taken to avoid race conditions in your code, as the callbacks will be called from the visualization thread.

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#include <pcl/visualization/cloud_viewer.h>
#include <iostream>
#include <pcl/io/io.h>
#include <pcl/io/pcd_io.h>
    
int user_data;
    
void 
viewerOneOff (pcl::visualization::PCLVisualizer& viewer)
{
    viewer.setBackgroundColor (1.0, 0.5, 1.0);
    pcl::PointXYZ o;
    o.x = 1.0;
    o.y = 0;
    o.z = 0;
    viewer.addSphere (o, 0.25, "sphere", 0);
    std::cout << "i only run once" << std::endl;
    
}
    
void 
viewerPsycho (pcl::visualization::PCLVisualizer& viewer)
{
    static unsigned count = 0;
    std::stringstream ss;
    ss << "Once per viewer loop: " << count++;
    viewer.removeShape ("text", 0);
    viewer.addText (ss.str(), 200, 300, "text", 0);
    
    //FIXME: possible race condition here:
    user_data++;
}
    
int 
main ()
{
    pcl::PointCloud<pcl::PointXYZRGBA>::Ptr cloud (new pcl::PointCloud<pcl::PointXYZRGBA>);
    pcl::io::loadPCDFile ("my_point_cloud.pcd", *cloud);
    
    pcl::visualization::CloudViewer viewer("Cloud Viewer");
    
    //blocks until the cloud is actually rendered
    viewer.showCloud(cloud);
    
    //use the following functions to get access to the underlying more advanced/powerful
    //PCLVisualizer
    
    //This will only get called once
    viewer.runOnVisualizationThreadOnce (viewerOneOff);
    
    //This will get called once per visualization iteration
    viewer.runOnVisualizationThread (viewerPsycho);
    while (!viewer.wasStopped ())
    {
    //you can also do cool processing here
    //FIXME: Note that this is running in a separate thread from viewerPsycho
    //and you should guard against race conditions yourself...
    user_data++;
    }
    return 0;
}

Compiling and running the program

Add the following lines to your CMakeLists.txt file:

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cmake_minimum_required(VERSION 2.8 FATAL_ERROR)

project(cloud_viewer)

find_package(PCL 1.2 REQUIRED)

include_directories(${PCL_INCLUDE_DIRS})
link_directories(${PCL_LIBRARY_DIRS})
add_definitions(${PCL_DEFINITIONS})

add_executable (cloud_viewer cloud_viewer.cpp)
target_link_libraries (cloud_viewer ${PCL_LIBRARIES})

After you have made the executable, you can run it like so:

$ ./cloud_viewer