I am currently rotate my camera in this way:

                camera.rotateAround( Axis.ORIGO, Axis.X, MyGestureListener.mYSpan );
                camera.rotateAround( Axis.ORIGO, Axis.Y, MyGestureListener.mXSpan );

But it is a weird rotation, I need something like this: https://threejsdoc.appspot.com/doc/three.js/examples/webgl_trackballcamera_earth.html

How can I implement is in libgdx?

Thanks,

Leslie