public void previousViewpoint(){
  if (viewpointList.size() == 0) {
    return;
  }
  viewpointIndex--;
  if (viewpointIndex < 0) {
    viewpointIndex=viewpointList.size() - 1;
  }
  viewpointNode.setViewpoint(viewpointList.get(viewpointIndex),true,true);
}

public void previousViewpoint ( ) { if ( viewpointList . size ( ) == 0 ) { return ; } viewpointIndex -- ; if ( viewpointIndex < 0 ) { viewpointIndex = viewpointList . size ( ) - 1 ; } viewpointNode . setViewpoint ( viewpointList . get ( viewpointIndex ) , true , true ) ; }
go to the previous viewpoint in the list
