Programming With QuickTime VR 2.1
QuickTime allows you to install a movie drawing complete procedure (by calling the SetMovieDrawingCompleteProc function), which is called whenever QuickTime is finished drawing a movie. The Show Hotspots button in the QuickTime VR movie controller bar uses a movie drawing complete procedure when drawing the hot spots on object nodes. A movie can have only one movie drawing complete procedure. As a result, if you need to use a movie drawing complete procedure for object nodes, you can either suppress the Show Hotspots button (to prevent the user from displaying hot spots) or intercept clicks on that button and provide your own function to show hot spots.
This restriction applies only to object nodes. Panoramic nodes do not use a movie drawing complete procedure to draw hot spots. Hot spots are drawn on panoramic nodes before your application's prescreen buffer imaging complete procedure is called (if you have one).