14.4 - Finding Out About Remote VR-Forces Applications

DtVrfRemoteController uses a DtVrfBackendListener (vrfBeListener.h) to keep track of all currently available remote VR-Forces applications.

VR-Forces applications send status heartbeats to alert remote control applications like vrfGui of their presence. The DtVrfBackendListener receives these messages, and maintains a list of DtSimulationAddress pointers identifying these applications. You can access this list using DtVrfRemoteController::backendList(). For example, to send a newScenario() command to just the first VR-Forces application on the list, do the following:

DtVrfRemoteController controller(&conn);
DtListItem* item = controller.backendList().first();
if (item)
{
   DtSimulationAddress* addr = (DtSimulationAddress*) item->data();
   controller.newScenario(*addr);  
}

VR-Forces remote control applications, such as vrfGui, need to be notified of the status of VR-Forces applications, so that they can update their GUIs, or otherwise notify the user which back-ends are available, for example, when issuing a createEntity() command. To do this, register back-end discovery callbacks or back-end removal callbacks with the DtVrfBackendListener (through the DtVrfRemoteController). Use

DtVrfRemoteController's add/removeBackendDiscoveryCallback() and add/removeBackendRemovalCallbacks() to register and unregister your callbacks.

As an alternative to using DtVrfBackendListener, you can find out information about back-ends through DtBackend (backend.h). You can ask for information about a specific back-end, which may be more convenient than using DtVrfBackendListener and DtVrfRemoteController. The DtVrfRemoteController maintains a DtBackEnd for each back-end in the session. The DtBackEnd get updated via the status messages that each back-end sends.

To look up information about a back-end, use the DtVrfBackendListener::lookupBackend() member function.

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