From Stephan Huber, "attached you'll find a proposal for handling multi-touch-events with

osgGA. My approach is to bundle all touchpoints into one custom data
structure which is attached to an GUIEventAdapter.

The current approach simulates a moving mouse for the first touch-point,
so basic manipulators do work, sort of.

I created a MultiTouchTrackballManipulator-class, one touch-point does
rotate the view, two touch-points pan and zoom the view as known from
the iphone or other similar multi-touch-devices. A double-tap (similar
to a double-click) resets the manipulator to its home-position.

The multi-touch-trackball-implementation is not the best, see it as a
first starting point. (there's a demo-video at http://vimeo.com/15017377 )"

src/osgGA/EventQueue.cpp

@@ -344,6 +344,57 @@ void EventQueue::keyRelease(int key, double time)
     addEvent(event);
 }
 
+
+GUIEventAdapter*  EventQueue::touchBegan(unsigned int id, GUIEventAdapter::TouchPhase phase, float x, float y, double time)
+{
+    // emulate left mouse button press
+    
+    _accumulateEventState->setButtonMask((1) | _accumulateEventState->getButtonMask());
+    _accumulateEventState->setX(x);
+    _accumulateEventState->setY(y);
+    
+    GUIEventAdapter* event = new GUIEventAdapter(*_accumulateEventState);
+    event->setEventType(GUIEventAdapter::PUSH);
+    event->setTime(time);
+    event->addTouchPoint(id, phase, x, y, 0);
+  
+    addEvent(event);
+    
+    return event;
+}
+        
+        
+GUIEventAdapter*  EventQueue::touchMoved(unsigned int id, GUIEventAdapter::TouchPhase phase, float x, float y, double time)
+{
+    _accumulateEventState->setX(x);
+    _accumulateEventState->setY(y);
+
+    
+    GUIEventAdapter* event = new GUIEventAdapter(*_accumulateEventState);
+    event->setEventType(GUIEventAdapter::DRAG);
+    event->setTime(time);
+    event->addTouchPoint(id, phase, x, y, 0);
+    addEvent(event);
+    
+    return event;
+}
+
+GUIEventAdapter*  EventQueue::touchEnded(unsigned int id, GUIEventAdapter::TouchPhase phase, float x, float y, unsigned int tap_count, double time)
+{
+    _accumulateEventState->setButtonMask(~(1) & _accumulateEventState->getButtonMask());
+    _accumulateEventState->setX(x);
+    _accumulateEventState->setY(y);
+    
+    GUIEventAdapter* event = new GUIEventAdapter(*_accumulateEventState);
+    event->setEventType(GUIEventAdapter::RELEASE);
+    event->setTime(time);
+    event->addTouchPoint(id, phase, x, y, tap_count);
+    addEvent(event);
+    
+    return event;
+}
+        
+
 void EventQueue::closeWindow(double time)
 {
     GUIEventAdapter* event = new GUIEventAdapter(*_accumulateEventState);