virtual bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter&) { if (ea.getEventType() == osgGA::GUIEventAdapter::LEFT_MOUSE_BUTTON && ea.getButton() == osgGA::GUIEventAdapter::RELEASE) { // left mouse button has been released return true; } return false; }
virtual bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter&) { if (ea.getEventType() == osgGA::GUIEventAdapter::SCROLL && ea.getScrollingMotion() == osgGA::GUIEventAdapter::SCROLL_DOWN && ea.getButton() == osgGA::GUIEventAdapter::NONE) { // scroll down event return true; } return false; }In this example, the `handle()` function is used to detect a scroll down event (i.e. when the user scrolls down on their input device). It checks if the event type is a `SCROLL`, if the scrolling motion is `SCROLL_DOWN`, and if no button on the input device was pressed. If all conditions are true, the function returns `true`. Both examples use the `getButton()` function to retrieve information about the input device button that triggered the event. The package library used is the OpenSceneGraph (OSG) Graphics Library.