FSX Retrieving AI data

[bcs112]

Hi all,

I am having problems collecting AI data for my TCAS display from SimConnect:

void CALLBACK MyDispatchProcMI(SIMCONNECT_RECV* pData, DWORD cbData, void *pContext)
{
   HRESULT hr;
   DWORD dwData;

    switch(pData->dwID)
    {
        
		////////////////////////////////////////////////
		// AI Traffic
		////////////////////////////////////////////////
		case SIMCONNECT_RECV_ID_EVENT_OBJECT_ADDREMOVE:
        {
            SIMCONNECT_RECV_EVENT_OBJECT_ADDREMOVE *evt = (SIMCONNECT_RECV_EVENT_OBJECT_ADDREMOVE*)pData;
            
            switch(evt->uEventID)
            {
                case EVENT_ADDED_AIRCRAFT:
			if ( evt->eObjType == SIMCONNECT_SIMOBJECT_TYPE_AIRCRAFT )
			{
				hr = SimConnect_RequestDataOnSimObject(hSimConnect, REQUEST_AIAIRCRAFT_DATA, DEFINITION_AI,
                        evt->dwData, SIMCONNECT_PERIOD_SECOND, SIMCONNECT_DATA_REQUEST_FLAG_CHANGED );
				AddTCASData(evt->dwData);
			}
                    break;

                case EVENT_REMOVED_AIRCRAFT:
			if ( evt->eObjType == SIMCONNECT_SIMOBJECT_TYPE_AIRCRAFT )
			{
				hr = SimConnect_RequestDataOnSimObject(hSimConnect, REQUEST_AIAIRCRAFT_DATA, DEFINITION_AI,
                        evt->dwData, SIMCONNECT_PERIOD_NEVER, SIMCONNECT_DATA_REQUEST_FLAG_CHANGED );
				RemoveTCASData(evt->dwData);
			}
			break;
            }
            break;
        }

	case SIMCONNECT_RECV_ID_SIMOBJECT_DATA:
        {
            SIMCONNECT_RECV_SIMOBJECT_DATA_BYTYPE *pObjData = (SIMCONNECT_RECV_SIMOBJECT_DATA_BYTYPE*)pData;
            
            switch(pObjData->dwRequestID)
            {
                case REQUEST_AIAIRCRAFT_DATA:
                {
                    DWORD ObjectID = pObjData->dwObjectID;
                    PositionData *pS = (PositionData*)&pObjData->dwData;
					UpdateTCASData(ObjectID, *pS);
                    break;
                }

                default:
                   break;
            }
            break;
        }

        case SIMCONNECT_RECV_ID_QUIT:
        {
            SimConnectQuit = 1;
            break;
        }

        default:
        break;
    }
}

void OpenSimConnect()
{
    HRESULT hr;

    if (SUCCEEDED(SimConnect_Open(&hSimConnect, "SimConnect", NULL, 0, 0, 0)))
    {
        hr = SimConnect_SubscribeToSystemEvent(hSimConnect, EVENT_ADDED_AIRCRAFT, "ObjectAdded");
        hr = SimConnect_SubscribeToSystemEvent(hSimConnect, EVENT_REMOVED_AIRCRAFT, "ObjectRemoved");	
		
 	SimConnect_CallDispatch(hSimConnect, MyDispatchProcMI, NULL);
    }
}

The ObjectAdded and ObjectRemoved work fine but the SIMCONNECT_RECV_ID_SIMOBJECT_DATA event is called a few times for the last aircraft added by FSX and then simply stops working.

I am probably missing something but I can't find what !

Any ideas anyone ?

Thx,
Björn

 

[bcs112]

Just to let you know that I was able to fix the issue myself.

Björn

 

[Simon853]

Not sure what fix you found, but I can tell you why I think your sample above doesn't work:

Your calls to RequestClientData() need unique request ids, so that as each aircraft is added, your request doesn't overwrite the previous request for the previous aircraft. You can reuse the id if the calls are few and far between and you only want to do a PERIOD_ONCE call, but to continue to receive updates, you can't.

What I do is set up my request enums like this:

enum REQUEST_ID
{
  REQUEST_SOMETHING = 0,
..
blah, blah
..
  REQUEST_AI_DATA = 10000,
  REQUEST_MO_SOMETHINGS = 20000,
..
..

That when I call the RequestDataOnSimObject, for the request id I use REQUEST_ID_DATA+objectId.

It means you have to use if-then-else in the callback instead of switch-case for the request ids, but it works. To get the object id that the callback data is relevent to, just subtract REQUEST_AI_DATA from the request id.

Si