public AboveVisitor(Mask mask,RegionFunction function,int baseY){
  super(mask,function);
  checkNotNull(mask);
  this.baseY=baseY;
  Collection<Vector> directions=getDirections();
  directions.clear();
  directions.add(new Vector(1,0,0));
  directions.add(new Vector(-1,0,0));
  directions.add(new Vector(0,0,1));
  directions.add(new Vector(0,0,-1));
  directions.add(new Vector(0,1,0));
  directions.add(new Vector(0,-1,0));
}

public AboveVisitor ( Mask mask , RegionFunction function , int baseY ) { super ( mask , function ) ; checkNotNull ( mask ) ; this . baseY = baseY ; Collection < Vector > directions = getDirections ( ) ; directions . clear ( ) ; directions . add ( new Vector ( 1 , 0 , 0 ) ) ; directions . add ( new Vector ( - 1 , 0 , 0 ) ) ; directions . add ( new Vector ( 0 , 0 , 1 ) ) ; directions . add ( new Vector ( 0 , 0 , - 1 ) ) ; directions . add ( new Vector ( 0 , 1 , 0 ) ) ; directions . add ( new Vector ( 0 , - 1 , 0 ) ) ; }
create a new visitor .
