title: pcl visualizer, rendering windows in threads
body: <p>I have created a class containing a thread of pclvisualizer. see this <a href="https://stackoverflow.com/questions/21155658/using-pclvisualization-in-different-threads-from-different-instance-of-a-cla">discussion</a>.</p>
  
  <p>and I  have found that the problem arises from the function "Interactor->Render" when you try to refresh the point cloud visualizer windows.</p>
  
  <p>although there is no conflict between threads (no shared data and ...), when two different threads from different objects enter the function "render" this error produced:</p>
  
  <pre><code>Access violation reading location 0x0000000000000010.
  </code></pre>
  
  <p>here is the piece of the intractor_style.cpp file, where the error occurs:</p>
  
  <pre><code>pcl::visualization::PCLVisualizerInteractorStyle::OnTimer ()
  {
    if (!init_)
    {
      pcl::console::print_error ("[PCLVisualizerInteractorStyle] Interactor style not initialized. Please call Initialize () before continuing.\n");
      return;
    }
  
    if (!rens_)
    {
      pcl::console::print_error ("[PCLVisualizerInteractorStyle] No renderer collection given! Use SetRendererCollection () before continuing.\n");
      return;
    }
    rens_-&gt;Render ();
    Interactor-&gt;Render (); /*error occurs here*/
  }
  </code></pre>