1 files changed, 4 insertions, 2 deletions
diff --git a/demos/opengl/trackball.h b/demos/opengl/trackball.h
index 29413becd..e9a899586 100644
--- a/demos/opengl/trackball.h
+++ b/demos/opengl/trackball.h
@@ -33,9 +33,11 @@ class Trackball
 {
   public:
 
+    enum Mode {Around, Local};
+
     Trackball() : mpCamera(0) {}
 
-    void reset() { mLastPointOk = false; }
+    void start(Mode m = Around) { mMode = m; mLastPointOk = false; }
 
     void setCamera(Camera* pCam) { mpCamera = pCam; }
 
@@ -46,8 +48,8 @@ class Trackball
     bool mapToSphere( const Eigen::Vector2i& p2, Eigen::Vector3f& v3);
 
     Camera* mpCamera;
-    Eigen::Vector2i mLastPoint2D;
     Eigen::Vector3f mLastPoint3D;
+    Mode mMode;
     bool mLastPointOk;
 
 };