コード例 #1
0
  public List<Point> createPath(final TerrainMap map) {
    final ArrayList<Point> path = new ArrayList<Point>();
    Point CurrentPoint = new Point(map.getStartPoint());

    HashMap<Point, Point> from = new HashMap<Point, Point>();
    HashMap<Point, Double> cost = new HashMap<Point, Double>();

    from.put(map.getStartPoint(), null);
    cost.put(map.getStartPoint(), 0.0);

    Queue<Point> frontier =
        new PriorityQueue<Point>(
            new Comparator<Point>() {
              public int compare(Point n1, Point n2) {
                double cost1 = cost.get(n1) + getHeuristic(map, map.getEndPoint(), n1);
                double cost2 = cost.get(n2) + getHeuristic(map, map.getEndPoint(), n2);
                if (cost1 > cost2) return 1;
                else if (cost1 < cost2) return -1;
                else return 0;
              }
            }); // frontier

    frontier.add(map.getStartPoint());

    while (!frontier.isEmpty()) {
      CurrentPoint = frontier.remove();

      if (CurrentPoint.equals(map.getEndPoint())) break;

      Point[] next = map.getNeighbors(CurrentPoint);

      for (int i = 0; i < next.length; i++) {
        double newCost = cost.get(CurrentPoint) + map.getCost(CurrentPoint, next[i]);

        if (!cost.containsKey(next[i]) || newCost < cost.get(next[i])) {
          cost.put(next[i], newCost);
          frontier.add(next[i]);
          from.put(next[i], CurrentPoint);
        }
      }
    }

    CurrentPoint = map.getEndPoint();
    path.add(CurrentPoint);

    while (!CurrentPoint.equals(map.getStartPoint())) {
      CurrentPoint = from.get(CurrentPoint);
      path.add(0, CurrentPoint);
    }

    return path;
  }
コード例 #2
0
 private double getHeuristic(final TerrainMap map, final Point pt1, final Point pt2) {
   // return 0;
   int d = Math.max(Math.abs(pt1.x - pt2.x), Math.abs(pt1.y - pt2.y));
   double h = map.getTile(pt2) - map.getTile(pt1);
   return d * Math.exp(h / d);
 }