Windows Creation Error - Maybe event handling - c++

Question

I'm trying to create an OpenGL context with WinAPI, it works great, but I think I messed up something, because when I click on the upper bar (where close button, minimize button is), it calls the ResizeWindow function somehow...Image showing this
Here is my main function:
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd)
{
GLWindow *window = new GLWindow();
Event *evt = new Event();
window->Create("OpenGL Window", 800, 600, 32);
while (window->IsRunning())
{
evt->Clear();
while (window->DispatchEvent(evt))
{
}
Render();
window->Present();
}
delete evt;
delete window;
}
Event is just a class with a map for containing event params. I removed every event handling in WndProc so it couldn't be a problem
Window creation code:
bool GLWindow::Create(char* title, int width, int height, int bits)
{
GLuint PixelFormat;
WNDCLASS wClass;
DWORD dwExStyle;
DWORD dwStyle;
RECT WindowRect;
WindowRect.left = (long)0;
WindowRect.top = (long)0;
WindowRect.right = (long)width;
WindowRect.bottom = (long)height;
hInstance = GetModuleHandle(NULL);
wClass.cbClsExtra = 0;
wClass.cbWndExtra = 0;
wClass.hbrBackground = (HBRUSH)GetStockObject(LTGRAY_BRUSH);
wClass.hCursor = LoadCursor(hInstance, IDC_ARROW);
wClass.hIcon = LoadIcon(hInstance, IDI_APPLICATION);
wClass.hInstance = hInstance;
wClass.lpfnWndProc = &GLWindow::WndProc;
wClass.lpszClassName = "GL";
wClass.lpszMenuName = NULL;
wClass.style = CS_VREDRAW | CS_HREDRAW | CS_OWNDC;
dwStyle = WS_OVERLAPPEDWINDOW;
dwExStyle = WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;
if (!RegisterClass(&wClass))
{
MessageBox(NULL, "Error! Cannot register window class!", "ERROR", MB_OK);
return 0;
}
AdjustWindowRectEx(&WindowRect, dwStyle, false, dwExStyle);
if (!(hWnd = CreateWindowEx(
dwExStyle,
"GL",
"Title",
WS_CLIPSIBLINGS | WS_CLIPCHILDREN | dwStyle,
0,
0,
WINDOW_WIDTH,
WINDOW_HEIGHT,
NULL,
NULL,
hInstance,
NULL)))
{
KillWindow();
MessageBox(NULL, "Window creation error.", "Error", MB_OK);
return false;
}
static PIXELFORMATDESCRIPTOR pfd =
{
sizeof(PIXELFORMATDESCRIPTOR),
1, //Version number
PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER | PFD_TYPE_RGBA, //Formats
bits, //color depth
0, 0, 0, 0, 0, 0, //color bits ignored
0, //no alpha buffer
0, //shift bit ignored
0, //no accumulation buffer
0, 0, 0, 0, //accumulation bits ignored
16, //16bit Zbuffer (depth buffer)
0, //no stencilbuffer
0, //no auxiliary buffer
PFD_MAIN_PLANE, //main drawing layer
0, //reserved
0, 0, 0 //layer masks ignored
};
if (!(hDC = GetDC(hWnd)))
{
KillWindow();
MessageBox(NULL, "Can't create OpenGL Window", "Error", MB_OK);
return false;
}
if (!(PixelFormat = ChoosePixelFormat(hDC, &pfd)))
{
KillWindow();
MessageBox(NULL, "Can't find suitable PixelFormat", "Error", MB_OK);
return false;
}
if (!SetPixelFormat(hDC, PixelFormat, &pfd))
{
KillWindow();
MessageBox(NULL, "Can't set pixelformat", "Error", MB_OK);
return false;
}
if (!(hRC = wglCreateContext(hDC)))
{
KillWindow();
MessageBox(NULL, "Can't create OpenGL context", "Error", MB_OK);
return false;
}
if (!wglMakeCurrent(hDC, hRC))
{
KillWindow();
MessageBox(NULL, "Can't activate OGL context", "Error", MB_OK);
return false;
}
ShowWindow(hWnd, SW_SHOW);
SetForegroundWindow(hWnd);
SetFocus(hWnd);
ResizeWindow(800, 600);
if (!InitGL())
{
KillWindow();
MessageBox(NULL, "Failed initialization", "Error", MB_OK);
return false;
}
return true;
}
Dispatching events:
bool GLWindow::DispatchEvent(Event* evt)
{
MSG msg;
bool wasThereAnyEvent = PeekMessage(&msg, NULL, 0, 0, PM_REMOVE);
if (wasThereAnyEvent)
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return wasThereAnyEvent;
}
I removed event buffer filling, so it just processes every message.
WndProc:
LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch (msg)
{
case WM_CREATE:
break;
case WM_DESTROY:
case WM_QUIT:
case WM_CLOSE:
isRunning = false;
PostQuitMessage(0);
return 0;
case WM_ACTIVATE:
{
isActiveWindow = !HIWORD(wParam);
return 0;
}
case WM_SYSCOMMAND:
switch (wParam)
{
case SC_SCREENSAVE:
case SC_MONITORPOWER:
return 0;
}
case WM_SIZE:
ResizeWindow(LOWORD(lParam), HIWORD(lParam));
return 0;
}
return DefWindowProc(hWnd, msg, wParam, lParam);
}

Answer 1

I think the problem is that you're not using any breaks inside you switch statement (of course they won't be needed in every case). When you receive a WM_SYSCOMMAND which not contains SC_SCREENSAVE or SC_MONITORPOWER the next case statement, in this case WM_SIZE, gets executed.
switch (msg)
{
case WM_CREATE:
break;
case WM_DESTROY:
case WM_QUIT:
case WM_CLOSE:
isRunning = false;
PostQuitMessage(0);
return 0;
break;
case WM_ACTIVATE:
{
isActiveWindow = !HIWORD(wParam);
return 0;
} break;
case WM_SYSCOMMAND:
{
switch (wParam)
{
case SC_SCREENSAVE:
case SC_MONITORPOWER:
return 0;
}
} break;
case WM_SIZE:
ResizeWindow(LOWORD(lParam), HIWORD(lParam));
return 0;
}