Basic demonstration of DirectInput exclusive mouse usage.  Lets
you draw on the screen with the mouse.  Note that this is not
particularly well-suited to DirectInput because the app acts
pretty much like a normal Windows application, but at least you
can see how the calls are made.  Right-click to display a menu
of options.

This sample program demonstrates the following:

* Creating interfaces to DirectInputDevice objects.

* Acquiring and unacquiring devices.

* Reading buffered device data.

* Event notifications for device activity.

* Restricting the mouse to an arbitrary region.

* Scaling raw mouse coordinates before using them.

* Use of relative axis mode.

