From Cory Riddell, "I added an _allowThrow boolean along with a getter and setter to the

spherical manipulator. The default value is true.

This is very similar to the flag in trackball."

include/osgGA/SphericalManipulator

@@ -109,6 +109,11 @@ class OSGGA_EXPORT SphericalManipulator : public MatrixManipulator
         RotationMode getRotationMode() const {return _rotationMode;}
         void setRotationMode(RotationMode mode);
 
+         /** Returns true if the camera can be thrown, false otherwise. This defaults to true. */
+        bool getAllowThrow() const { return _allowThrow; }
+        /** Set the 'allow throw' flag. Releasing the mouse button while moving the camera results in a throw. */
+        void setAllowThrow(bool allowThrow) { _allowThrow = allowThrow; }
+
     protected:
 
         virtual ~SphericalManipulator();
@@ -136,6 +141,7 @@ class OSGGA_EXPORT SphericalManipulator : public MatrixManipulator
         double _minimumZoomScale;
 
         bool _thrown;
+        bool _allowThrow;
 
         RotationMode    _rotationMode;
         osg::Vec3d      _center;

src/osgGA/SphericalManipulator.cpp

@@ -13,6 +13,7 @@ SphericalManipulator::SphericalManipulator()
     _modelScale = 0.01;
     _minimumZoomScale = 0.1;
     _thrown = false;
+    _allowThrow = true;
 
     _distance=1.0;
     _homeDistance=1.0;
@@ -149,7 +150,7 @@ bool SphericalManipulator::handle(const GUIEventAdapter& ea,GUIActionAdapter& us
                     {
                         us.requestRedraw();
                         us.requestContinuousUpdate(true);
-                        _thrown = true;
+                        _thrown = _allowThrow;
                     }
                 }
                 else