Simple CGF (simpleCGF)

Table of Contents

• How to Run the Example
  • Usage
• Main Application File

The Simple CGF example demonstrates the following:

• How to create a CGF
• How to create objects within this CGF

A CGF application differs from the released back-end in that there is not command line options applied to it and it is intended to be used as part of a larger back-end application that does not have a need to interface with the VR-Forces front-end.

How to Run the Example

This example demonstrates how to create a simple CGF application (outside of the context of the vrfSim application). It shows how to create an embedded CGF in an non-VR-Forces application.

Usage

To run the application:

1. Open a command prompt window and navigate to the VR-Forces /bin64/ directory.
2. Start just the VR-Forces vrfGUI (frontend) through the Launcher - using the command "vrfLauncher -F"
3. From the Launcher - start VR Forces using the preconfigured DIS (7) connection (rather than "DIS (7) localhost")
4. Do not load an existing or create a new scenario.
5. Open the ($SharedDataDir)/TerrainData/TerrainConfiguration/Ground_DB II.mtf terrain database.

6. Open a separate command prompt window, navigate to the VR-Forces /bin64/ directory and start simpleCgf from the command prompt with the --deviceAddress option as "simpleCGFDIS --deviceAddress <deviceAddress>" - e.g.:

     simpleCGFDIS.exe --deviceAddress 127.0.0.1
   
     Note:
     The necessary front-end command line arguments can be copied from the Launcher UI.
   

7. Join the session if propmpted by the vrfGui depending on application settings for sessions.
8. The simpleCgf application creates a tank tasked to move toward a waypoint in the Ground_DB II.mtf terrain.
9. A tank and waypoint will appear in the display, and the tank will immediately begin moving toward the waypoint.

Main Application File

/*******************************************************************************
** Copyright (c) 2004 MAK Technologies, Inc.
** All rights reserved.
*******************************************************************************/


//This example demonstrates how to use the DtCgf class to create objects
//and task entities, as you would if you were to embed VR-Forces in your own 
//application.

#ifdef WIN32
#include <winsock2.h>
#include <windows.h>
#endif

//VR-Forces Headers
#include "vrfcgf/cgf.h"
#include "vrfcgf/cgfDispatcher.h"
#include "vrftasks/moveToTask.h"
#include "vrfobjcore/localObject.h"

//VR-Link headers
#include <vl/exerciseConn.h>
#include <vl/exerciseConnInitializer.h>
#include <vlutil/vlPrint.h>
#include <vlutil/vlProcessControl.h>
#include <vl/hostStructs.h>
#include "vrfutil/vrfVlKeyboard.h"

// Instead of an exercise connection, the cgf must now be initialized with a communication manager that
// contains the supported network protocols
#include <vrfMsgTransport/communicationManager.h>
#include <vrlinkNetworkInterface/vrlinkNetworkInterface.h>

using namespace makVrf;

int main(int argc, char *argv[])
{
   //DIS/RPR simulation address

   DtSimulationAddress simAddress(1, 3001);

   //Create the CGF
   DtCgf* cgf = new DtCgf(simAddress);

   // The following is left so the user can see how to piece together a 
   // simple DIS or HLA exercise connection. Also so you know what execName to 
   // pass for HLA for the -x command. Use this and you don't need anything else, it will use 
   // a default fed file of VR-Link.fed(for HLA13) or VR-Link.xml( for HLA1516/1516e) However to make life easier we're also 
   // going to show you how to use an DtVrlApplicationInitializer so you can parse the command line as well
   //Create the exercise connection
/*#if DtHLA

   DtString execName           = "VR-Link";     //HLA federation execution name
   DtString federateName       = "simpleCgf";   //HLA federate name
   double rprFomVersion        = 1.0;           //RPR FOM version number

   DtExerciseConn* exerciseConn = new DtExerciseConn(execName, federateName,
      new DtRprFomMapper(rprFomVersion));

#else //DIS

   int port = 3928;                             //UDP port number
   int exerciseId = 1;                          //DIS exercise ID

   DtExerciseConn* exerciseConn = new DtExerciseConn(port, DtInetAddr("127.255.255.255"),exerciseId, 
      simAddress.siteId(), simAddress.applicationId());

#endif*/

   // Use this to parse the command line then pass the initializer to the exercise connection
   DtVrlApplicationInitializer initializer(argc, argv, "simpleCgf");

#if DtDIS
   initializer.setDisVersionToSend(7);
#endif

   initializer.parseCmdLine();

#if DtDIS
   initializer.setSiteId(simAddress.siteId());
   initializer.setApplicationNumber(simAddress.applicationId());
#endif

   DtExerciseConn* exerciseConn = new DtExerciseConn(initializer);

   // Turn off warnings for too many PDUs sent in a second as this is expected on terrain that is very hilly or has a lot
   // of quick altitude changes
   DtObjectPublisher::setDfltUpdateRateWarningThreshold(10000);

   DtCommunicationManager* communicationManager = DtCommunicationManager::createCommunicationManager(simAddress);
   DtVrlinkNetworkInterface* vrliface = DtVrlinkNetworkInterface::createVrlinkNetworkInterface(exerciseConn);

   communicationManager->addManager(vrliface);

   //Initialize the CGF
   cgf->init(communicationManager);

   //Create the dispatcher so this application can interface with
   //front-end
   DtCgfDispatcher* cgfDispatcher = new DtCgfDispatcher(cgf,
      cgf->simulationServices()->messageInterface());

   //Create a new scenario, using the Ground-db.gdb terrain database and the EntityLevel
   //simulation model set to allow for entity creation.  Also create a global environment and dynamic terrain object
   cgf->newScenario(DtFilename("$(SHARED_DATA_DIR)/TerrainData/TerrainConfiguration/Ground_DB II.mtf"),
      DtFilename("$(DATA_DIR)/simulationModelSets/EntityLevel.sms"), true, true);
   //Tick the cgf to get the terrain loaded
   cgf->tick();
   
   //Create a tank
   DtEntityType tankType(1, 1, 225, 1, 1, 3, 0);
   DtVector initialPosition(133.1, 164.6, 21.3); //Database coordinates, meters
   DtReal initialHeading = 0.0;                 //Heading in radians
   //At this point the simulation has not yet been started, so when creating
   //entities it's best to call createEntity without specifying the
   //"allowBlocking" parameter to allow it default to true. This will insure
   //that when using a paging terrain, the necessary pages will immediately
   //get paged in.
   DtLocalObject* tank = cgf->createEntity(
      tankType,                                 
      DtForceFriendly,                          
      initialPosition,              
      initialHeading);                                     

   //Create a waypoint named "Alpha"
   
   DtLocalObject* alpha = cgf->createWaypoint(
      DtVector(200.0, 300.0, 18.0),            
      "Alpha");

   //Put the simulation engine into run mode. This will tick the nav
   // interface to make sure the task below can execute using the nav area 
   // if it exists in the terrain.
   cgf->run();

   //Tell the tank to move to waypoint "Alpha"
   DtMoveToTask moveToTask;
   moveToTask.setControlPoint(alpha->uuid());

   cgf->assignTask(tank, moveToTask);

   //Used below to insure only one example entity is created at runtime
   bool entityCreatedAtRuntime = false;

   //Main application loop
   while (1)
   {
      //tick the CGF Dispatcher
      cgfDispatcher->tick();
       
      //tick the CGF
      cgf->tick();

      //Poll & process keyboard input
      char *keyPtr = DtGetInputLine();
      if (keyPtr && *keyPtr == 'q')
      {
         break;
      } 

      //Give up the remainder of our time slice.
      DtSleep(0.01);
      
      //This is an example of creating an entity at runtime
      if (!entityCreatedAtRuntime)
      {
         //Change the initial position so this entity isn't created on top of
         //the first one
         initialPosition.setX(75);
         //In this case when calling createEntity, the allowBlocking flag must
         //be set to false. If the entity being created requires a new tile to
         //be swapped in, the simulation can't block while it gets loaded in
         //without having a negative effect on the models.
         cgf->createEntity(tankType, DtForceFriendly, initialPosition,              
            initialHeading, DtString::nullString(), false);
         //reset the flag so only one entity gets created
         entityCreatedAtRuntime = true;
      }
   }    

   delete cgf;
   delete communicationManager;
   delete exerciseConn;

   return 0;
}