Setting Device Windows

There are two ways to set a device window:

• Create a window yourself and pass its handle to the IDirectDraw4::SetCooperativeLevel method of the DirectDraw object representing the monitor, setting the DDSCL_SETDEVICEWINDOW, DDSCL_FULLSCREEN, and DDSCL_EXCLUSIVE flags. This creates a full-screen window and sets it as the device window for the monitor. Your application will receive mouse messages for the window, and you are responsible for destroying the window at the appropriate time. The window you pass to SetCooperativeLevel should be either the focus window (possible only if it is on the same device) or a child of the focus window.
• Let DirectDraw create the window. You pass the focus window handle to SetCooperativeLevel and set the DDSCL_CREATEDEVICEWINDOW, DDSCL_FULLSCREEN, and DDSCL_EXCLUSIVE flags. DirectDraw creates a default device window that is a child of the focus window. It manages this window and will destroy it at the appropriate time. Your application will not receive any mouse messages for the window.

The following example sets an existing device window for the DirectDraw object represented by lpDD.

/* It is presumed that lpDD is a valid IDirectDraw interface pointer,
   and that hWnd is the handle to an appropriate device window. */
 
HRESULT hr = lpDD->SetCooperativeLevel( hWnd,
        DDSCL_SETDEVICEWINDOW | DDSCL_EXCLUSIVE | DDSCL_FULLSCREEN );
 

The following example sets a default device window created by DirectDraw. In this case, hWnd is the handle to the existing focus window.

HRESULT hr = lpDD->SetCooperativeLevel( hWnd,
        DDSCL_CREATEDEVICEWINDOW | DDSCL_EXCLUSIVE | DDSCL_FULLSCREEN );
 

Although a focus window can be a device window, you cannot set a window as both the focus window and a device window with a single call to SetCooperativeLevel. You must first set it as the focus window and then set it as a device window. However, it is possible to set a focus window and a default device window on the same device with a single call to SetCooperativeLevel. The following example shows how this can be done:

HRESULT hr = lpDD->SetCooperativeLevel(
        hwndFocus,
        DDSCL_SETFOCUSWINDOW | DDSCL_FULLSCREEN |
        DDSCL_EXCLUSIVE | DDSCL_CREATEDEVICEWINDOW);
 

In this example, an existing window (probably the application window) is set as the focus window, and DirectDraw creates a default device window.