Overview

A driver accessory is an interface for executing code when a driver starts. An accessory is registered with the display engine and can support any driver class that it knows how to interface with. This example is an empty template accessory to use as a starting point.

Expected Result

N/A

Example details

When the exampleAccessoryPlugin gets loaded, it's passed a DtDe (display engine). At that point we connect the post initialize signal (which will get emitted after the display engine has been initialized) to the function we want to call, loadAccessory.

      // The accessory must be created after the DE's initialization is
      // finished, to make sure all the objects it uses exist.
      de.signal_postInitialize.connect(boost::bind(
         &loadAccessory, &de));

When loadAccessory gets called after the display engine is initialized we add our accessory. In this case, it prints out something when entities are discovered.

void loadAccessory(DtDe* de)
{
   // We're done with the signal, so disconnect from it
   de->signal_postInitialize.disconnect(boost::bind(
      &loadAccessory, de));
   // Add the accessory to the accessory manager. It will get the option
   // to install itself into any DtDriver objects that are created.
   DtAccessoryManager::instance(*de).addAccessory(new MyAccessory());
}

An accessory has three pure virtual methods that need to be implemented. When it's time to install accessories, the display engine goes through its list of accessors and tries to install each one on every driver. The accessory has a method, isCompatible() that determines if the accessory can be installed on the driver. If so, then it's installed. Later, the accessories are uninstalled from the driver.

      bool MyAccessory::isCompatible(DtDriver* driver)
      {
         // This accessory is compatible with any DtVrlinkDriver
         DtVrlinkDriver* dd = dynamic_cast<DtVrlinkDriver*>(driver);
         if(dd)
         {
            return true;
         }
         return false;

Once deemed compatible, the display engine gives the driver to the accessory, which installs itself. From there the accessory can do what it wants.

Building the Example

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

Running the Example

N/A

Example Source Files

exampleAccessoryTemplatePlugin.h

/******************************************************************************
** Copyright (c) 2019 MAK Technologies, Inc.
** All rights reserved.
******************************************************************************/
#pragma once
// Get proper local export symbol
#include "exampleAccessoryTemplate.h"
// Setup proper plugin export symbol
#define DT_DE_PLUGIN_EXPORT_MACRO DT_DLL_EXAMPLEACCESSORYTEMPLATE
// Declare & export the plugin initialization function (bool initDeModule(DtDe* de))
#include <vrvCore/exportPlugin.h>
namespace makVrv 
{ 
   class DtDe; 
}
// Work function for the plugin initialization
DT_DLL_EXAMPLEACCESSORYTEMPLATE void init(makVrv::DtDe& de);
// Callback to load the DtAccessoryDriver into the display engine
void loadAccessory(makVrv::DtDe* de);

exampleAccessoryTemplatePlugin.cxx

/******************************************************************************
** Copyright (c) 2014 MAK Technologies, Inc.
** All rights reserved.
******************************************************************************/
#include "exampleAccessoryTemplatePlugin.h"
#include <vrvCore/DtDe.h>
#include <vrvCore/DtAccessoryManager.h>
#include <boost/bind.hpp>
// Define export macro for vrvVrl includes
#define DL_DLL_IGCONVRLINK DT_DLL_EXAMPLEACCESSORYTEMPLATE
// Define the protocol specific macros to compile for HLA13
#define DT_PROTOCOL_NAMESPACE vrvHla13
// #define DtHLA 1
// #define RTI_USES_STD_FSTREAM 1
#include "MyAccessory.h"
using namespace makVrv;
using namespace makVrv::DT_PROTOCOL_NAMESPACE;
#undef DT_PROTOCOL_NAMESPACE
// #undef DtHLA
// #undef RTI_USES_STD_FSTREAM
void loadAccessory(DtDe* de)
{
   // We're done with the signal, so disconnect from it
   de->signal_postInitialize.disconnect(boost::bind(
      &loadAccessory, de));
   // Add the accessory to the accessory manager. It will get the option
   // to install itself into any DtDriver objects that are created.
   DtAccessoryManager::instance(*de).addAccessory(new MyAccessory());
}
void init(DtDe& de)
{
   // Ensure that init only gets called once
   // (not strictly necessary here, but this is good practice in general)
   DT_DE_INIT_ONCE(de);
   // We only want to create the accessory if we're running in master mode:
   if (de.isInMasterMode())
   {
      // The accessory must be created after the DE's initialization is
      // finished, to make sure all the objects it uses exist.
      de.signal_postInitialize.connect(boost::bind(
         &loadAccessory, &de));
   }
}
bool initDeModule(makVrv::DtDe* de)
{
   // Setup the plug-in. Normally, the init function and functionality
   // should be in its own library.
   init(*de);
   return true;
}

MyAccessory.h

/******************************************************************************
** Copyright (c) 2019 MAK Technologies, Inc.
** All rights reserved.
******************************************************************************/
#pragma once
#include "exampleAccessoryTemplate.h"
#include <vrvCore/DtBaseAccessory.h>
namespace makVrv
{
   class DtConnection;
   namespace DT_PROTOCOL_NAMESPACE
   {
      class MyAccessory : public DtBaseAccessory
      {
      public:
         MyAccessory();
         virtual ~MyAccessory();
         virtual bool isCompatible(DtDriver* driver);
         virtual void install(DtDriver* driver);
         virtual void uninstall(DtDriver* baseConn);
      protected:
         virtual void slot_onSimCreated(DtConnection* connection);
         virtual void slot_onSimConnected(DtConnection* connection);
         virtual void slot_onSimAboutToBeDisconnected(DtConnection* connection);
      };
   }
}
#include "MyAccessory.inl"

MyAccessory.inl

/******************************************************************************
** Copyright (c) 2019 MAK Technologies, Inc.
** All rights reserved.
******************************************************************************/
#include "exampleAccessoryTemplate.h"
#include <vrvVrl/DtVrlinkConnection.h>
#include <vrvVrl/DtVrlinkDriver.h>
#include <boost/bind.hpp>
#include <iostream>
#include <RTI.hh>
#include <vl/exerciseConn.h>
#include <vl/fom.h>
namespace makVrv
{
   namespace DT_PROTOCOL_NAMESPACE
   {
   
#ifdef DtDIS
      static std::string accessoryName="MyAccessoryDis";
#else
#ifdef DtHLA_1516
   #ifdef DtHLA_1516_EVOLVED
      static std::string accessoryName="MyAccessoryHla1516e";
   #else
      static std::string accessoryName="MyAccessoryHla1516";
   #endif
#else
   static std::string accessoryName="MyAccessoryHla13";
#endif
#endif
      MyAccessory::MyAccessory()
      :   DtBaseAccessory(accessoryName)
      {
      }
      MyAccessory::~MyAccessory()
      {
      }
      bool MyAccessory::isCompatible(DtDriver* driver)
      {
         // This accessory is compatible with any DtVrlinkDriver
         DtVrlinkDriver* dd = dynamic_cast<DtVrlinkDriver*>(driver);
         if(dd)
         {
            return true;
         }
         return false;
      }
      void MyAccessory::install(DtDriver* driver)
      {
         //std::cout << "Accessory install" << std::endl;
         DtVrlinkDriver* vld = dynamic_cast<DtVrlinkDriver*>(driver);
         if(vld)
         {
            vld->signal_simulationCreated.connect(
               boost::bind(&MyAccessory::slot_onSimCreated, this, _1));
         }
      }
      void MyAccessory::uninstall(DtDriver* baseConn)
      {
         //std::cout << "Accessory unInstall" << std::endl;
         DtVrlinkDriver* vld = dynamic_cast<DtVrlinkDriver*>(baseConn);
         if(vld)
         {
            vld->signal_simulationCreated.disconnect(
               boost::bind(&MyAccessory::slot_onSimCreated, this, _1));
         }
      }
      void MyAccessory::slot_onSimCreated(DtConnection* connection)
      {
         connection->signal_connected.connect(
            boost::bind(&MyAccessory::slot_onSimConnected, this, connection));
         connection->signal_toBeDisconnected.connect(
            boost::bind(&MyAccessory::slot_onSimAboutToBeDisconnected, this, connection));
      }
      void MyAccessory::slot_onSimConnected(DtConnection* connection)
      {
         DtVrlinkConnection* vrlCon = dynamic_cast<DtVrlinkConnection*>(connection);
         if(vrlCon)
         {
            // Here you can install register object creators, as well as access the
            // VR-Link exercise connection
            DtExerciseConn& exConn = *(vrlCon->exerciseConn());
            DtObjClassDesc* classDesc = exConn.fom()->
               objClassByName("BaseEntity.PhysicalEntity");
            if (NULL != classDesc)
            {
               classDesc->unsubscribe();
            }
            classDesc = exConn.fom()->
               objClassByName("BaseEntity.PhysicalEntity.Lifeform");
            if (NULL != classDesc)
            {
               classDesc->unsubscribe();
            }
            classDesc = exConn.fom()->
               objClassByName("BaseEntity.PhysicalEntity.Lifeform.Human");
            if (NULL != classDesc)
            {
               classDesc->unsubscribe();
            }
            classDesc = exConn.fom()->
               objClassByName("BaseEntity.PhysicalEntity.Lifeform.NonHuman");
            if (NULL != classDesc)
            {
               classDesc->unsubscribe();
            }
         }
      }
      void MyAccessory::slot_onSimAboutToBeDisconnected(DtConnection* sim)
      {
         DtVrlinkConnection* vrlsim=dynamic_cast<DtVrlinkConnection*>(sim);
         if(vrlsim)
         {
            // Do any necessary cleanup here
         }
      }
   }
}

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