From Stephan Huber, "attached you'll find a first version of multi-touch-support for OS X (>=

10.6), which will forward all multi-touch events from a trackpad to the
corresponding osgGA-event-structures.

The support is switched off per default, but you can enable multi-touch
support via a new flag for GraphicsWindowCocoa::WindowData or directly
via the GraphicsWindowCocoa-class.

After switching multi-touch-support on, all mouse-events from the
trackpad get ignored, otherwise you'll have multiple events for the same
pointer which is very confusing (as the trackpad reports absolute
movement, and as a mouse relative movement).

I think this is not a problem, as multi-touch-input is a completely
different beast as a mouse, so you'll have to code your own
event-handlers anyway.

While coding this stuff, I asked myself if we should refactor
GUIEventAdapter/EventQueue and assign a specific event-type for
touch-input instead of using PUSH/DRAG/RELEASE. This will make it
clearer how to use the code, but will break the mouse-emulation for the
first touch-point and with that all existing manipulators. What do you
think? I am happy to code the proposed changes.

Additionally I created a small (and ugly) example osgmultitouch which
makes use of the osgGA::MultiTouchTrackballManipulator, shows all
touch-points on a HUD and demonstrates how to get the touchpoints from
an osgGA::GUIEventAdapter.

There's even a small example video here: http://vimeo.com/31611842"

include/osgGA/EventQueue

@@ -218,6 +218,8 @@ class OSGGA_EXPORT EventQueue : public osg::Referenced
         /** Method for adapting user defined events with specified event time */
         void userEvent(osg::Referenced* userEventData, double time);
 
+        void setFirstTouchEmulatesMouse(bool b) { _firstTouchEmulatesMouse = b; }
+        bool getFirstTouchEmulatesMouse() const { return _firstTouchEmulatesMouse; }
 
     protected:
 
@@ -233,6 +235,7 @@ class OSGGA_EXPORT EventQueue : public osg::Referenced
         osg::Timer_t                _startTick;
         mutable OpenThreads::Mutex  _eventQueueMutex;
         Events                      _eventQueue;
+        bool                        _firstTouchEmulatesMouse;
     
 };