FSX SimConnect vs. Windows message loop

[KWB]

I have a console application with SimConnect, this gives me the first
message loop / callback combination:

while( 0 == quit ) {
 SimConnect_CallDispatch(hSimConnect, MyDispatchProcMI, NULL);
 Sleep(50);
}

Within my application I create a window planned to serve as a child window in FSX.
Here I have a second message loop:

MSG msg;
while (GetMessage(&msg, NULL, 0, 0)) {
  TranslateMessage(&msg);  
  DispatchMessage(&msg);
}

Since I hardly can have two loops, I see the following options:

1. One loop runs in an independent thread, which is at least not possible for window message loops.
2. The SimConnect handling goes in the Windows Message loop
3. Vice versa, the DispatchMessage for the window goes in the SimConnect loop

Which is the right way to proceed? And hints, suggestions?


Updated: I can merge them both in the SimConnect loop, this works. But is the way to go?

MSG msg;
while (0 == quit)  {
	if (hSimWindowInclude && PeekMessage(&msg, hSimWindowInclude, 0, 0, PM_REMOVE)) {
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	SimConnect_CallDispatch(hSimConnect, MyDispatchProcMI, NULL);
	Sleep(50);
}

 

[TOWSIM]

It is possible to run a Windows message loop in an own thread. I do that particularly for OGL or DirectX windows to protect the graphics from unnecessary system messages. Even the SimConnect loop runs in an own threat. But you have to take care for some process specific rules. Especially when you try to use SimConnect out of another thread. Or using Windows DCs out of another thread.
Regards
Mike

 

[TOWSIM]

An amendment to my previous answer (I should have red the link before):
What they describe is a mismatch of the procedure how a message loop works. Every windows runs in thread. If you want to get it running in an own thread, you have to do something like this:

void A10_AUX_WIN::AUXwindowPump(void)
{
	MSG msg;
	WNDCLASS wc;
	HINSTANCE hInstance;
	hInstance = GetModuleHandle(NULL);
	wc.style = CS_HREDRAW | CS_VREDRAW;
	wc.lpfnWndProc = (WNDPROC) ClassQueue;
	wc.cbClsExtra = 0;
	wc.cbWndExtra = 0;
	wc.hInstance = hInstance;
	wc.hIcon = LoadIcon(hInstance,IDI_APPLICATION);
	wc.hCursor = LoadCursor(NULL, IDC_ARROW);
	wc.hbrBackground = (HBRUSH)GetStockObject(NULL_BRUSH);
	wc.lpszMenuName = NULL;
	wc.lpszClassName = szAppNam;
	RegisterClass(&wc);

	AppRep->Protocoll(1,"Registered Window class");

	thisWindow = CreateWindowEx(	0,szAppNam,
		"",
		WS_OVERLAPPEDWINDOW | WS_VISIBLE,
		iniX, iniY, iniWidth, iniHight,
		NULL,
		NULL,
		hInstance,
		NULL );
	while(GetMessage(&msg,thisWindow,0,0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	AppRep->Protocoll(1,"Thread ended...");
	CloseHandle(thrHdl);
	thrHdl = NULL;

}

AUXwindowPump is a thread body that serves a DirectX window in a DLL. As you can see in the message pump loop, I use the handle of the newly created window in GetMessage. I think that is the difference to your description. The window can be addressed like every other window, with SendMessage or PostMessage.
Regards
Mike

 

[KWB]

Thanks / SimConnect in independent thread

Thanks for the nice example TOWSIM, great stuff.

You've mentioned some prerequisites about running SimConnect in an own thread. What are they, is there some kind of documentation about running SimConnect in an independent thread or have you figured this out own your own?

 

[TOWSIM]

I take special care, that all handling routines called out of the dispatcher and even the calls to a SimConnect function are in the same thread. I made the experience, that some SimConnect functions fail, if you call them from a different thread. Whereby, if you are called from SimConnect via the dispatcher, you are in a different thread. In this special case it is possible to call the interface. Different thread means, a thread which did not open the SimConnect interface. The real advantage calling SimmConnect out of a thread is, you have all control over the timing and you are not disturbed by other functions. Unfortunately there is no description for these trap doors. May be, I didn't find one up to now.
Regards
Mike

 

[KWB]

Thanks a lot again for your time and effort! I am just beginning with this stuff, so pointing out the right path surely saves me a lot of time!