public Tuple <CoverNode <T>, SpatialObj <T> > IncrementalNNFindNext() { if (incrNN_queue is null) { return(null); } while (incrNN_queue.Count > 0) { NodeOrObj current_element = incrNN_queue.Dequeue(); while (incrNN_queue.Count > 0 && incrNN_queue.First().Equals(current_element)) { incrNN_queue.Dequeue(); } if (current_element.IsObj()) { return(Tuple.Create(current_element.GetNode(), current_element.GetObj())); } else { CoverNode <T> current_node = current_element.GetNode(); double current_dist = current_node.GetDistanceToPointSq(incrNN_origin); if (!current_node.IsEmpty()) { foreach (SpatialObj <T> obj in current_node.GetAllObjects()) { double distance = obj.boundingBox.GetDistanceSqToPoint(incrNN_origin); if (distance >= current_dist) { NodeOrObj obj_nodeOrObj = new NodeOrObj(); obj_nodeOrObj.SetNode(current_node); obj_nodeOrObj.SetObj(obj); incrNN_queue.Enqueue(obj_nodeOrObj, (float)distance); } } } if (current_node.HasChildren()) { foreach (CoverNode <T> child_node in current_node.GetChildren()) { double distance = child_node.GetDistanceToPointSq(incrNN_origin); if (distance >= current_dist) { NodeOrObj node_nodeOrObj = new NodeOrObj(); node_nodeOrObj.SetNode(child_node); incrNN_queue.Enqueue(node_nodeOrObj, (float)distance); } } } } } return(null); }