question: public void nextViewpoint ( ) { if ( viewpointList . size ( ) == 0 ) { return ; } viewpointIndex ++ ; if ( viewpointIndex >= viewpointList . size ( ) ) { viewpointIndex = 0 ; } viewpointNode . setViewpoint ( viewpointList . get ( viewpointIndex ) , true , true ) ; }
target:  Go to the next viewpoint in the list