exampleCreator

The exampleCreator example uses the creator pattern to cause a derived channel to get created when the display engine creates a channel. Here is the object class:

class MyExampleChannel : public DtOsgChannel
{
public:

   friend class MyExampleChannelCreator;

   virtual ~MyExampleChannel()
   {
   }

protected:

   MyExampleChannel( DtDe& de, DtOsgWindow* window, DtChannelConfiguration& channelConfig )
      : DtOsgChannel( de, window, channelConfig )
   {
      // Do nothing. This is an example of registering a class using the creator pattern.

      // osgViewer::View* view = view();
      // osg::Camera* camera = camera();
   }

};

Notice the protected constructor. This is because we are going to use a creator to create our channel. Here is the creator for the object class:

class MyExampleChannelCreator : public DtChannelCreator
{
public:

   virtual DtChannel* create( DtDe& de, DtWindow* window,
      DtChannelConfiguration& config )
   {
      DtOsgWindow* osgWindow = dynamic_cast<DtOsgWindow*>(window);
      if (!osgWindow)
      {
         return 0;
      }

      MyExampleChannel* myExampleChannel = new MyExampleChannel(de, osgWindow, config);
      // initialize the channel to create the view, root node, observer object,
      // setup cameras, etc.
      if (myExampleChannel->initialize())
      {
         return myExampleChannel;
      }
      else
      {
         return 0;
      }
   }

};

This creator is derived from the DtChannelCreator (DtChannel.h):

Building the Example

VR-Vantage includes pre-built versions of the example application. To build it yourself, follow the instructions at Building VR-Vantage Examples, Applications, and Plug-ins.

Running the Example

This example is an application. You can run it by running ./bin64/exampleCreator.exe (on Windows) or ./bin64/exampleCreator (on Linux). For more information about running examples, please see Running Applications and Examples.

---

exampleCreator.cxx

/*****************************************************************************
 * Copyright (c) 2012 MaK Technologies, Inc.
 * All rights reserved.
 *****************************************************************************/


#include <vrvCore/DtVrvApplication.h>

#include <vrvOsg/DtOsgChannel.h>
#include <vrvOsg/DtOsgWindow.h>

#include <boost/bind.hpp>

// Use the VR-Vantage namespace. All classes in VR-Vantage are in this namespace.
using namespace makVrv;

// An example derived channel.
// This shows how to create and register your own channel with the DtDisplayEngine.
// This example demonstrates the Creator Pattern.
class MyExampleChannel : public DtOsgChannel
{
public:

   friend class MyExampleChannelCreator;

   virtual ~MyExampleChannel()
   {
   }

protected:

   MyExampleChannel( DtDe& de, DtOsgWindow* window, DtChannelConfiguration& channelConfig )
      : DtOsgChannel( de, window, channelConfig )
   {
      // Do nothing. This is an example of registering a class using the creator pattern.

      // osgViewer::View* view = view();
      // osg::Camera* camera = camera();
   }

};

class MyExampleChannelCreator : public DtChannelCreator
{
public:

   virtual DtChannel* create( DtDe& de, DtWindow* window,
      DtChannelConfiguration& config )
   {
      DtOsgWindow* osgWindow = dynamic_cast<DtOsgWindow*>(window);
      if (!osgWindow)
      {
         return 0;
      }

      MyExampleChannel* myExampleChannel = new MyExampleChannel(de, osgWindow, config);
      // initialize the channel to create the view, root node, observer object,
      // setup cameras, etc.
      if (myExampleChannel->initialize())
      {
         return myExampleChannel;
      }
      else
      {
         return 0;
      }
   }

};

// A DtVrvApplication wraps up all the components required to build a complete
// VR-Vantage application (DtDe, DtPluginManager, DtEventLoop, and a 
// DtVrvApplicationConfiguration).
//
// This derived application simply overrides the postLoadPluginModules() call
// to register our example channel after the plugins are loaded.
class MyExampleApplication : public DtVrvApplication
{
public:

   MyExampleApplication()
      : DtVrvApplication()
   {
      DtVrvApplication::ApplicationTransform functor = boost::bind(
         &MyExampleApplication::postLoadPluginModules, this, _1, _2, _3 );
      installPostPluginTransform( functor, "postPluginTransform" );
   }

protected:

   virtual void postLoadPluginModules( DtDeInitializer& deInit, DtDe& de,
      DtVrvApplicationConfiguration& config )
   {
      // Register the channel creator
      DtChannelCreator::registerInstance( *myDe, new MyExampleChannelCreator() );
   }

};

int main( int argc,char* argv[] )
{
   // Create the example application class.
   MyExampleApplication application;

   // This causes the plugin manager to load plugins, cause a Display Configuration
   // to be realized, creates the default environment, etc.
   application.initialize(argc, argv);

   // Creates an event loop and begins running it, causing the creation of frames.
   application.run();

   return 0;
}