I've created a win32 C++ app that uses direct2d to plot stuff in a window. In a loop as shown below, I call render and update whilst also peeking at any messages. But when ever I have WM_COMMAND that lets WindowProc call a MessageBox() or DiaLogBox(), my update&render loop no longer gets executed and the plot window freezes. Is there a simple fix with another loop structure or do I need to enter the, for me, unknown world of multithreading?
while (message.message != WM_QUIT)
{
if (PeekMessage(&message, NULL, 0, 0, PM_REMOVE))
DispatchMessage(&message);
else
{
Update();
BeginDraw();
Render();
EndDraw();
}
}
EDIT: By popular demand I have changed above "ugly" mechanism in to another approach, yet with the same issue
bool runGame = true;
while (runGame)
{
while (PeekMessage(&message, NULL, 0, 0, PM_REMOVE))
{
DispatchMessage(&message);
if (message.message == WM_QUIT)
runGame = false;
}
Update();
BeginDraw();
Render();
EndDraw();
}
Related
Following a Direct2D tuturial I've created a realtime update&render-loop like below. But when the update&render-loop takes long (eg when I have a Sleep(5000) somewhere in the Update()), normal messages handling like clicking the close window, can have to wait up to 5s.
So what is the proper way to split the message handling and realtime update&render-loop in two separate threads?
while (message.message != WM_QUIT)
{
if (PeekMessage(&message, windowHandle, 0, 0, PM_REMOVE)) // check for events and pass them to WindowProc, otherwise
DispatchMessage(&message);
else // run the realtime update&render loop
{
GameController::Update();
graphics->BeginDraw();
GameController::Render();
graphics->EndDraw();
}
}
I have a weird problem over here. I created a DLL proxy for Spotify so I can "overlay" a button onto it. Basicially, thats how it works:
DllMain
-> Creates CMain class
-> Creates CToggleButton class
-> Hooks the button onto the Spotify window
It has two methods, one static one which I use for the thread since threads can't call member functions, and one non-static function which gets called by the member function.
With this, I create the thread and pass an instance of the CToggleButton class via lpParam:
CreateThread(0, NULL, WindowThreadStatic, (void*)this, NULL, NULL);
Then, the WindowThreadStatic function:
DWORD WINAPI CToggleButton::WindowThreadStatic(void* lpParam)
{
return ((CToggleButton*)lpParam)->WindowThread();
}
And the main window thread function inside the class:
DWORD CToggleButton::WindowThread()
{
MSG msg;
hButton = CreateWindowA("BUTTON", "Test", (WS_VISIBLE | WS_CHILD), 0, 0, 100, 20, parenthWnd, NULL, hInst, NULL);
bool bQueueRunning = true;
while (bQueueRunning)
{
if (PeekMessage(&msg, parenthWnd, 0, 0, PM_REMOVE))
{
switch (msg.message)
{
case WM_QUIT:
bQueueRunning = false;
break;
case WM_LBUTTONDOWN:
if (msg.hwnd == hButton)
{
MessageBoxA(parenthWnd, "Button!", "Button", MB_OK);
continue;
}
}
TranslateMessage(&msg);
DispatchMessage(&msg);
}
Sleep(10);
}
return 0;
}
As you can see, this also contains the message loop for the button (I didn't use GetMessage() here because it was very unresponsive so I decided to use PeekMessage() together with a 10ms delay, which works fine.)
Little picture to show how it looks like:
All great, but if I maximize the window, the button disappears. When I minimize and maximize the window a few times, the button can be seen again, but with very weird coordinates (not the original 0,0 I gave him).
So what is my problem here? Why do the coordinates get offset?
Thanks for reading my long post :)
I have a single window created with the CS_OWNDC style for an engine I'm coding and it's showing properly, but when I'm closing the program and I call the ReleaseDC(hWnd, hDC) the function returns 0 always (and according to MSDN it means it couldn't be released).
The DestroyWindow(hWnd) is also returning 0.
I am calling GetDC(hWnd) during the window creation.
What is weird is that I only get this error if I pass through the messaging function, even if it has nothing coded inside.
My main code is looking like this:
WindowManager windowManager;
HWND mainWindow = windowManager.Initialize("Title", "ClassName", 1024, 768, 32, WindowProc);
MSG msg;
while(true)
{
if(PeekMessage(&msg, 0, 0, 0, PM_REMOVE))
{
if(msg.message == WM_QUIT) { break; }
else
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
}
windowManager.Clear(); //this calls ReleaseDC(hWnd, DC) and DestroyWindow(hWnd) among other release codes
What I don't understand is that if I comment the whole while loop, I don't get the release or destroy window errors.
Calling GetLastError() gives me a 0 too.
On MSDN it says the DestroyWindow must be called from the same thread, but I'm not coding any multi thread functions so I don't think that's the case.
What could be causing this?
I have been messing around with OpenGL lately, and I noticed that the windows message pump is blocking whenever i attempt to resize my window, so as a result rendering is halted whenever i click on the menu bar or resize the window.
To fix this, I am looking into multithreading.
I have the following:
_beginthread(RenderEntryPoint, 0, 0);
while (!done)
{
PeekMessage(&msg, NULL, NULL, NULL, PM_REMOVE);
if (msg.message == WM_QUIT)
{
done = true;
}
else
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
void RenderEntryPoint(void *args)
{
while (1)
{
//render code
}
}
However, my scene isn't being rendered, and I'm not sure why.
You need to make the OpenGL rendering context current in the rendering thread, and make sure it's not current in the windowing thread. This also means that you can't call any OpenGL functions from the windowing thread.
I'm creating game mario like in win32 GDI . I've implemented the new loop for game :
PeekMessage(&msg,NULL,0,0,PM_NOREMOVE);
while (msg.message!=WM_QUIT)
{
if (PeekMessage(&msg,NULL,0,0,PM_REMOVE)) {
TranslateMessage(&msg);
DispatchMessage(&msg);
}
else // No message to do
{
gGameMain->GameLoop();
}
}
But my game just running until I press Ctrl + Alt + Del ( mouse cursor is rolling ).
I've always been using something like that:
MSG msg;
while (running){
if (PeekMessage(&msg, hWnd, 0, 0, PM_REMOVE)){
TranslateMessage(&msg);
DispatchMessage(&msg);
}
else
try{
onIdle();
}
catch(std::exception& e){
onError(e.what());
close();
}
}
onIdle is actual game lopp implementation, onError() is an error handler (takes error description as argument), and "running" is either a global bool variable or a class member. Setting "running" to false shuts down the game.
I think this really depends on your context. Windows will only send a WM_QUIT in response to your application calling PostQuitMessage. A common (if not great) solution here is to use a bool to exit the message loop when your program wants to end.
I guess the program may ask user for continue or exit, inside GameLoop function call. On exit Post WM_QUIT message to the window.
PostMessage(hWnd, WM_QUIT, 0, 0 );
hWnd-> The handle of the game window
else make a call to
DestroyWindow(hWnd);
This will send a WM_DESTROY to your window procedure. There you can call
PostQuitMessage(0);