Data Interaction Example

If users want to create and send arbitrary data, this example demonstrates how to use data interactions to encode and decode your information.

/****************************************************************************
 * Copyright (c) 2014 VT MAK
 * All rights reserved.
 ****************************************************************************/


#include <vl/exerciseConn.h>
#include <vl/exerciseConnInitializer.h>
#include <vl/setDataInteraction.h>
#include <vlutil/vlMiniDumper.h>

#include <vlutil/vlProcessControl.h>

#include <iostream>

void receiveData( DtSetDataInteraction* inter, void* )
{
    std::cout << "SetData Interaction from "
       <<  inter->senderId().string() << std::endl;

   if ( inter->numFixedFields() >= 2 )
   {
      std::cout << " Mass: " << inter->datumValFloat32(DtFixed, 1) << std::endl;
      std::cout << " Country: " << inter->datumValInt32(DtFixed, 2) << std::endl;
   }

   for ( int field = 1; field <= inter->numVarFields(); field++ )
   {
      std::cout << " " << inter->datumValByteArray(DtVar, field) << std::endl;
   }
}

int main( int argc, char* argv[] )
{
   // Used for error handling
   DtINIT_MINIDUMPER( "SetData" );

   try
   {
      // Create a connection to the exercise or federation execution.
      DtVrlApplicationInitializer appInit(argc, argv, "VR-Link Talk");

#if DtDIS
      // Change some defaults. Please note that this is DIS specific code.
      // Notice how this is the only line of DIS specific code in this example,
      // everything else is using the protocol independent API.
      appInit.setUseAsynchIO(true);
#endif

      // Process the command line. This will actually set values in the
      // DtVrlApplicationInitializer class and should be called before
      // creating the DtExerciseConn instance.
      appInit.parseCmdLine();

      // The DtExerciseConn instance is perhaps the most important class
      // in any VR-Link exercise. Think of it as the hub which holds
      // everything else together. Technically this instance is what's
      // responsible for connecting this federate to another federate via
      // a network, or an RTI. After exConn is created, and if no error
      // has occurred this simulator will be a live federate.
      DtExerciseConn exConn(appInit);

      DtSetDataInteraction::addCallback(&exConn, receiveData, 0);

      DtSetDataInteraction dataInter;
      DtEntityIdentifier senderId = DtEntityIdentifier(3, 4, 1);
      DtEntityIdentifier receiverId = DtEntityIdentifier(3, 4, 2);

      // Send a Data Interaction.
      dataInter.setRequestId(4);
      dataInter.setSenderId(senderId);
      dataInter.setReceiverId(receiverId);

      dataInter.setNumFixedFields(2);
      dataInter.setDatumParam(DtFixed, 1, DtDatumMass);
      dataInter.setDatumValFloat32(DtFixed, 1, 16.5);
      dataInter.setDatumParam(DtFixed, 2, DtDatumCountry);
      dataInter.setDatumValInt32(DtFixed, 2, 300);

      dataInter.setNumVarFields(3);
      dataInter.setVarDataBytes(1, sizeof("Hi there"));
      dataInter.setDatumParam(DtVar, 1, (DtDatumParam) 1122);
      dataInter.setVarDataBytes(2, sizeof("world"));
      dataInter.setDatumParam(DtVar, 2, (DtDatumParam) 2233);
      dataInter.setVarDataBytes(3, sizeof("Jimmy was here"));
      dataInter.setDatumParam(DtVar, 3, (DtDatumParam) 4567);
      dataInter.setDatumValByteArray(DtVar, 1, "Hi there");
      dataInter.setDatumValByteArray(DtVar, 2, "world");
      dataInter.setDatumValByteArray(DtVar, 3, "Jimmy was here");

      // Initialize VR-Link time.
      DtClock* clock = exConn.clock();

      // Main loop
      DtTime dt = 1;
      DtTime simTime = 0;
      while (simTime <= 60.0)
      {
         // Tell VR-Link the current value of simulation time.
         clock->setSimTime(simTime);

         // Process any incoming messages.
         exConn.drainInput();

       exConn.sendStamped(dataInter);

         simTime     += dt;

         // Wait till real time equals simulation time of next step.
         DtSleep(simTime - clock->elapsedRealTime());
      }
   }
   DtCATCH_AND_WARN(std::cout);
   return 0;
}