//-----------------------------------------------------------------------------
// MainWndProc
//
// The window procedure for the main window, deals with the different types
// of messages received
// ----------------------------------------------------------------------------
LRESULT CALLBACK WndProc(HWND hWnd, UINT msg,
WPARAM wParam, LPARAM lParam)
{
// If the message is WM_NCCREATE, associate Window pointer with this window
// Note: WM_NCCREATE is not the first message that this WndProc will process
// What happens here is that we assigned some extra space for the window which
// was of size of a pointer to a MainWnd object. Now in the WM_NCREATE message the
// lParam method is actually the class structure used to make the window i.e.
// CREATESTRUCT. In this stucture is a pointer to a MainWnd object. SetWindowLong in
// this usage sets the extra window data to this which can only be done on creation
if (msg == WM_NCCREATE) {
LPCREATESTRUCT cs = (LPCREATESTRUCT) lParam;
SetWindowLong(hWnd, GWL_USERDATA, (long) cs->lpCreateParams);
}
// get the MainWnd structure and pass the data to that
MainWnd* w = (MainWnd *) GetWindowLong(hWnd, GWL_USERDATA);
if (w)
return w->WndProc(hWnd, msg, wParam, lParam);
else
return DefWindowProc(hWnd, msg, wParam, lParam);
} // --- MainWndProc ----------------------------------------------------------
