Question

我正在尝试实现A *路径但是得到了错误的结果：

绿色斑点是道路，红色斑点是障碍。

具体来说这部分是错误的：

为什么要进入树然后再按照正确的路径进行操作？我错过了什么？

这是我的实施：

public List<Spot> process(GameBodyObject me, Point target, ArrayList<GameBodyObject> others) throws Exception {

    if(grid == null) {
        throw new Exception("You have to initialize AStar first.");
    }

    grid.unsetObstacleForObject(me);

    Spot start = grid.getSpotAtPosition(me.getPosition().getX(), me.getPosition().getY());
    Spot end = grid.getSpotAtPosition(target.getX(), target.getY());

    end = grid.moveSpotSoThatItDoesntCollide(end, me.getRadius());

    List<Spot> openSet = new ArrayList<Spot>(grid.getMaxSize());
    List<Spot> closedSet = new ArrayList<>();
    List<Spot> path = new ArrayList<>();

    openSet.add(start);

    while(openSet.size() > 0) {

        int winner = 0;
        for(int i = 1; i < openSet.size(); i++) {
            if(openSet.get(i).getF() < openSet.get(winner).getF()) {
                winner = i;
            }
        }

        Spot current = openSet.get(winner);

        /*int i = 1;
        for(Spot s : Arrays.asList(openSet.getArray())) {
            if(s != null) {
                System.out.println(i + ". " + s.getF());
                i++;
            }
        }*/

        if(current.equals(end)) {
            // We are done, reconstruct the path...
            Spot temp = current;
            path.add(temp);
            while(temp.getPrevious() != null) {
                path.add(temp.getPrevious());
                temp = temp.getPrevious();
            }

            grid.resetObstacles();
            return path;
        }

        openSet.remove(current);
        closedSet.add(current);

        List<Spot> neighbors = current.getNeighbors();

        for(Spot neighbor : neighbors) {
            if(!closedSet.contains(neighbor) && !grid.isCollidingWithObstacle(neighbor, me.getRadius())) {
                double tempG = current.getG() + 1;
                if(openSet.contains(neighbor)) {
                    if(tempG < neighbor.getG()) {
                        neighbor.setG(tempG);
                    }
                } else {
                    neighbor.setG(tempG);
                    openSet.add(neighbor);
                }

                neighbor.setH(heuristic(neighbor, end));
                neighbor.setF(neighbor.getG() + neighbor.getH());
                neighbor.setPrevious(current);
            }
        }

    }

    grid.resetObstacles();
    return new ArrayList<>();
}

public double heuristic(Spot spot, Spot end) {
    double dx = spot.getX() - end.getX();
    double dy = spot.getY() - end.getY();
    return Math.abs(dx) + Math.abs(dy);
}

Answer 1

因此我的heuristics似乎有问题，我将其更改为：

public double heuristic(Spot spot, Spot end) {
    double dx = spot.getAbsoluteX() - end.getAbsoluteX();
    double dy = spot.getAbsoluteY() - end.getAbsoluteY();
    //return Math.sqrt(dx * dx + dy * dy);
    return Math.abs(dx) + Math.abs(dy);
}

现在它运作正常。

A *找到无效路径

1 个答案: