From Jan Peciva, I have improved GraphicsWindowQt:

- renamed osgQt::GraphWidget to osgQt::GLWidget
as it better fits to Qt naming (osgQt::GLWidget is derived from QGLWidget
while recent GraphWidget... it is unclear, maybe QGraphicsView,
QGraphicsScene,....)
- added the code to properly manage ON_DEMAND rendering scheme
(involves osgQt::setViewer() and internal HeartBeat class)
- added forward key events functionality. It allows to not eat the key events
by GLWidget, but it forwards them to Qt processing as well.
- destroying GLWidget before GraphicsWindowQt and vice versa does not crash
the application
- it is possible to request particular QGLFormat in GLWidget constructor
- added QtWindowingSystem class
- multithread OSG rendering improvements/fixes

--

From Robert Osfield, added back in getGraphWidget() method for backwards compatibility.

include/osgQt/GraphicsWindowQt

@@ -15,26 +15,53 @@
 #define OSGVIEWER_GRAPHICSWINDOWQT
 
 #include <osgViewer/GraphicsWindow>
-
-#include <QtGui/QWidget>
-#include <QtGui/QInputEvent>
 #include <QtOpenGL/QGLWidget>
-
 #include <osgQt/Export>
 
+class QInputEvent;
+
+namespace osgViewer {
+    class ViewerBase;
+}
+
 namespace osgQt
 {
 
-class OSGQT_EXPORT GraphWidget : public QGLWidget
-{
-public:
-    GraphWidget( const QGLFormat& format, QWidget* parent=0, const QGLWidget* shareWidget=0, Qt::WindowFlags f=0 );
+// forward declarations
+class GraphicsWindowQt;
 
-    inline void setGraphicsWindow( osgViewer::GraphicsWindow* gw ) { _gw = gw; }
+/// The function sets the WindowingSystem to Qt.
+void OSGQT_EXPORT initQtWindowingSystem();
+
+/** The function sets the viewer that will be used after entering
+ *  the Qt main loop (QCoreApplication::exec()).
+ *
+ *  The function also initializes internal structures required for proper
+ *  scene rendering.
+ *
+ *  The method must be called from main thread. */
+void OSGQT_EXPORT setViewer( osgViewer::ViewerBase *viewer );
+
+
+class OSGQT_EXPORT GLWidget : public QGLWidget
+{
+    typedef QGLWidget inherited;
+public:
+
+    GLWidget( QWidget* parent = NULL, const QGLWidget* shareWidget = NULL, Qt::WindowFlags f = 0, bool forwardKeyEvents = false );
+    GLWidget( QGLContext* context, QWidget* parent = NULL, const QGLWidget* shareWidget = NULL, Qt::WindowFlags f = 0, bool forwardKeyEvents = false );
+    GLWidget( const QGLFormat& format, QWidget* parent = NULL, const QGLWidget* shareWidget = NULL, Qt::WindowFlags f = 0, bool forwardKeyEvents = false );
+    virtual ~GLWidget();
+
+    inline void setGraphicsWindow( GraphicsWindowQt* gw ) { _gw = gw; }
+    inline GraphicsWindowQt* getGraphicsWindow() { return _gw; }
+    inline const GraphicsWindowQt* getGraphicsWindow() const { return _gw; }
+
+    inline bool getForwardKeyEvents() const { return _forwardKeyEvents; }
+    virtual void setForwardKeyEvents( bool f ) { _forwardKeyEvents = f; }
 
     void setKeyboardModifiers( QInputEvent* event );
 
-    virtual void resizeEvent( QResizeEvent* event );
     virtual void keyPressEvent( QKeyEvent* event );
     virtual void keyReleaseEvent( QKeyEvent* event );
     virtual void mousePressEvent( QMouseEvent* event );
@@ -44,25 +71,44 @@ public:
     virtual void wheelEvent( QWheelEvent* event );
 
 protected:
-    osgViewer::GraphicsWindow* _gw;
+    friend class GraphicsWindowQt;
+    GraphicsWindowQt* _gw;
+
+    bool _forwardKeyEvents;
+
+    virtual void resizeEvent( QResizeEvent* event );
+    virtual void moveEvent( QMoveEvent* event );
+    virtual void glDraw();
+    virtual bool event( QEvent* event );
 };
 
 class OSGQT_EXPORT GraphicsWindowQt : public osgViewer::GraphicsWindow
 {
 public:
-    GraphicsWindowQt( osg::GraphicsContext::Traits* traits );
+    GraphicsWindowQt( osg::GraphicsContext::Traits* traits, QWidget* parent = NULL, const QGLWidget* shareWidget = NULL, Qt::WindowFlags f = 0 );
+    GraphicsWindowQt( GLWidget* widget );
     virtual ~GraphicsWindowQt();
 
-    inline GraphWidget* getGraphWidget() { return _widget; }
-    inline const GraphWidget* getGraphWidget() const { return _widget; }
+    inline GLWidget* getGLWidget() { return _widget; }
+    inline const GLWidget* getGLWidget() const { return _widget; }
 
-    struct WindowData : public osg::Referenced
+    /// deprecated
+    inline GLWidget* getGraphWidget() { return _widget; }
+    /// deprecated
+    inline const GLWidget* getGraphWidget() const { return _widget; }
+
+struct WindowData : public osg::Referenced
     {
-        WindowData( GraphWidget* widget ): _widget(widget) {}
-        GraphWidget* _widget;
+        WindowData( GLWidget* widget = NULL, GLWidget* parent = NULL ): _widget(widget), _parent(parent) {}
+        GLWidget* _widget;
+        GLWidget* _parent;
     };
 
-    bool init();
+    bool init( QWidget* parent, const QGLWidget* shareWidget, Qt::WindowFlags f );
+
+    static QGLFormat traits2qglFormat( const osg::GraphicsContext::Traits* traits );
+    static void qglFormat2traits( const QGLFormat& format, osg::GraphicsContext::Traits* traits );
+    static osg::GraphicsContext::Traits* createTraits( const QGLWidget* widget );
 
     virtual bool setWindowRectangleImplementation( int x, int y, int width, int height );
     virtual void getWindowRectangle( int& x, int& y, int& width, int& height );
@@ -87,13 +133,14 @@ public:
     virtual void requestWarpPointer( float x, float y );
 
 protected:
-    GraphWidget* _widget;
+    friend class GLWidget;
+
+    GLWidget* _widget;
+    bool _ownsWidget;
     QCursor _currentCursor;
-    bool _initialized;
     bool _realized;
 };
 
 }
 
 #endif
-