java可視化，實現走迷宮小遊戲（包含隨機迷宮生成、BFS自動尋找迷宮解）

本文是對我之前整理的一篇文章的續集，傳送門。主要是想實現隨機生成迷宮的算法並在此基礎上進行走迷宮的小遊戲。本程序適用於java程序員鞏固類與對象、文件讀取、事件響應、awt包中各種工具的相關概念以及對邏輯能力的鍛鍊。由於作者水平問題，本程序難免存在紕漏之處，如有提醒或者此代碼更多的補充，歡迎聯繫我vx：wjw0310。（我從來不吝惜給幫助過我的人發紅包哦~~）

最終效果如下：

數據層

設計 MazeData.java 類，來存儲和迷宮相關的數據，包括迷宮的大小（行、列），存儲迷宮、解的路徑的字符矩陣，出口和入口以及玩家的位置信息等並提供外部可調用的查詢方法。

此外，還設計了判斷某一座標是否在迷宮內、獲取迷宮某一座標處的信息的方法。

public class MazeData {

    public static final char ROAD = ' ';
    public static final char WALL = '#';

    private int N, M;
    public char[][] maze;
    public boolean[][] visited;
    public boolean[][] path;
    public Position player;
    public boolean showPath;

    private int entranceX, entranceY;
    private int exitX, exitY;

    public MazeData(int N, int M){

        if( N%2 == 0 || M%2 == 0)
            throw new IllegalArgumentException("Our Maze Generalization Algorihtm requires the width and height of the maze are odd numbers");

        this.N = N;
        this.M = M;

        maze = new char[N][M];
        visited = new boolean[N][M];
        path = new boolean[N][M];
        for(int i = 0 ; i < N ; i ++)
            for(int j = 0 ; j < M ; j ++){
                if(i%2 == 1 && j%2 == 1)
                    maze[i][j] = ROAD;
                else
                    maze[i][j] = WALL;

                visited[i][j] = false;
                path[i][j] = false;
            }
        showPath = false;

        entranceX = 1;
        entranceY = 0;
        exitX = N - 2;
        exitY = M - 1;

        maze[entranceX][entranceY] = ROAD;
        maze[exitX][exitY] = ROAD;
    }

    public int N(){ return N; }
    public int M(){ return M; }
    public int getEntranceX(){ return entranceX; }
    public int getEntranceY(){ return entranceY; }
    public int getExitX(){ return exitX; }
    public int getExitY(){ return exitY; }

    public boolean inArea(int x, int y){
        return x >= 0 && x < N && y >= 0 && y < M;
    }

    public char getMaze(int i, int j){
        if (!inArea(i, j))
            throw new IllegalArgumentException("i or j is out of index in getMaze!");

        return maze[i][j];
    }
}

同樣將迷宮的各個位置封裝成一個類 Position.java，便於操作，這裏不做贅述。詳情

視圖層

AlgoFrame.java 是繪製界面的核心代碼，使用java的JFrame控件，在上面添加JPanel畫板，在JFrame中定義渲染方法render來調用畫板的 paintComponent 方法實現繪製，其中需要用到自己定義的繪製輔助類 AlgoVisHelper.java，在裏面封裝了繪製矩形，設置畫筆顏色，停頓等方法，也定義了一些顏色，也可以不用定義該輔助類而直接在 AlgoFrame.java 中使用awt包中的各種方法直接實現，如有需要可自行下載代碼。
 

import java.awt.*;
import javax.swing.*;

public class AlgoFrame extends JFrame{

    private int canvasWidth;
    private int canvasHeight;

    public AlgoFrame(String title, int canvasWidth, int canvasHeight){

        super(title);

        this.canvasWidth = canvasWidth;
        this.canvasHeight = canvasHeight;

        AlgoCanvas canvas = new AlgoCanvas();
        setContentPane(canvas);
        pack();

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setResizable(false);

        setVisible(true);
    }

    public AlgoFrame(String title){

        this(title, 1024, 768);
    }

    public int getCanvasWidth(){return canvasWidth;}
    public int getCanvasHeight(){return canvasHeight;}

    // data
    private MazeData data;
    public void render(MazeData data){
        this.data = data;
        repaint();
    }

    private class AlgoCanvas extends JPanel{

        public AlgoCanvas(){
            // 雙緩存
            super(true);
        }

        @Override
        public void paintComponent(Graphics g) {
            super.paintComponent(g);

            Graphics2D g2d = (Graphics2D)g;

            // 抗鋸齒
            RenderingHints hints = new RenderingHints(
                    RenderingHints.KEY_ANTIALIASING,
                    RenderingHints.VALUE_ANTIALIAS_ON);
            hints.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
            g2d.addRenderingHints(hints);

            // 具體繪製
            int w = canvasWidth/data.M();
            int h = canvasHeight/data.N();

            for(int i = 0 ; i < data.N() ; i ++ )
                for(int j = 0 ; j < data.M() ; j ++){
                    if(data.maze[i][j] == MazeData.WALL)
                        AlgoVisHelper.setColor(g2d, AlgoVisHelper.LightBlue);
                    else
                        AlgoVisHelper.setColor(g2d, AlgoVisHelper.White);

                    if(data.path[i][j] && data.showPath == true)
                        AlgoVisHelper.setColor(g2d, AlgoVisHelper.Yellow);

                    if (data.player.getX() == i && data.player.getY() == j)
                        AlgoVisHelper.setColor(g2d, AlgoVisHelper.Red);

                    AlgoVisHelper.fillRectangle(g2d, j * w, i * h, w, h);
            }
        }

        @Override
        public Dimension getPreferredSize(){
            return new Dimension(canvasWidth, canvasHeight);
        }
    }
}

控制層

主函數 AlgoVisualizer.java ，初始化過程封裝在 initial 函數中，主要完成隨機迷宮的生成以及通過基於遞歸的DFS算法將迷宮的解事先求出，用戶按下空格則可以實現提示功能，紅色表示玩家，鍵盤上下左右控制四個方向的移動。run()方法實現了所有的動畫邏輯。

import java.awt.*;
import java.awt.event.*;

public class AlgoVisualizer {

    private static int DELAY = 5;
    private static int blockSide = 8;

    private MazeData data;
    private AlgoFrame frame;
    private static final int d[][] = {{-1,0},{0,1},{1,0},{0,-1}};

    public AlgoVisualizer(int N, int M){

        // 初始化數據
        data = new MazeData(N, M);
        int sceneHeight = data.N() * blockSide;
        int sceneWidth = data.M() * blockSide;

        // 初始化視圖
        EventQueue.invokeLater(() -> {
            frame = new AlgoFrame("Random Maze Generation Visualization", sceneWidth, sceneHeight);
            frame.addKeyListener(new AlgoKeyListener());

            new Thread(() -> {
                run();
            }).start();
        });
    }

    private void run(){

        setRoadData(-1, -1);

        if (initial())
            System.out.println("初始化已完成");

        while (true){
            frame.render(data);
            AlgoVisHelper.pause(DELAY);
        }

    }

    private boolean initial(){
        data.player = new Position(data.getEntranceX(), data.getEntranceY());
        RandomQueue<Position> queue = new RandomQueue<Position>();
        Position first = new Position(data.getEntranceX(), data.getEntranceY()+1);
        queue.add(first);
        data.visited[first.getX()][first.getY()] = true;

        while(queue.size() != 0){
            Position curPos = queue.remove();

            for(int i = 0 ; i < 4  ; i ++){
                int newX = curPos.getX() + d[i][0]*2;
                int newY = curPos.getY() + d[i][1]*2;

                if(data.inArea(newX, newY) && !data.visited[newX][newY]){
                    queue.add(new Position(newX, newY));
                    data.visited[newX][newY] = true;
                    setRoadData(curPos.getX() + d[i][0], curPos.getY() + d[i][1]);
                }
            }
        }
        for(int i = 0 ; i < data.N() ; i ++)
            for(int j = 0 ; j < data.M() ; j ++)
                data.visited[i][j] = false;
        new Thread(() -> {
            go(data.getEntranceX(), data.getEntranceY());
        }).start();
        return true;
    }

    private boolean go(int x, int y){

        if(!data.inArea(x,y))
            throw new IllegalArgumentException("x,y are out of index in go function!");

        data.visited[x][y] = true;
        setPathData(x, y, true);

        if(x == data.getExitX() && y == data.getExitY())
            return true;

        for(int i = 0 ; i < 4 ; i ++){
            int newX = x + d[i][0];
            int newY = y + d[i][1];
            if(data.inArea(newX, newY) &&
                    data.maze[newX][newY] == MazeData.ROAD &&
                    !data.visited[newX][newY])
                if(go(newX, newY))
                    return true;
        }

        // 回溯
        setPathData(x, y, false);

        return false;
    }

    private void setRoadData(int x, int y){
        if(data.inArea(x, y))
            data.maze[x][y] = MazeData.ROAD;
    }

    private void setPathData(int x, int y, boolean isPath){
        if(data.inArea(x, y))
            data.path[x][y] = isPath;
    }

    private class AlgoKeyListener extends KeyAdapter{

        @Override
        public void keyPressed(KeyEvent event){
            if (event.getKeyCode() == KeyEvent.VK_LEFT){
                System.out.println("go left");
                oneStep(data.player.getX(), data.player.getY(), 3);
            }
            else if (event.getKeyCode() == KeyEvent.VK_DOWN){
                System.out.println("go down");
                oneStep(data.player.getX(), data.player.getY(), 2);
            }
            else if (event.getKeyCode() == KeyEvent.VK_RIGHT){
                System.out.println("go right");
                oneStep(data.player.getX(), data.player.getY(), 1);
            }
            else if (event.getKeyCode() == KeyEvent.VK_UP){
                System.out.println("go up");
                oneStep(data.player.getX(), data.player.getY(), 0);
            }
            else if (event.getKeyChar() == ' '){
                System.out.println("顯示提示");
                data.showPath = !data.showPath;
            }
        }
    }

    private void oneStep(int x, int y, int direction){
        int newX = x + d[direction][0];
        int newY = y + d[direction][1];
        if (data.inArea(newX, newY) &&
                data.getMaze(newX, newY) == MazeData.ROAD){
            data.player.setX(newX);
            data.player.setY(newY);
        }
    }

    public static void main(String[] args) {

        int N = 101;
        int M = 101;

        AlgoVisualizer vis = new AlgoVisualizer(N, M);

    }
}

其中隨機迷宮的生成算法是使用隨機隊列的數據結構來實現的，隨機隊列底層基於java的鏈表類 LinkedList 來實現的，數據入隊的操作是隨機在頭部或尾部進行添加，數據出隊的操作是隨機在頭部或尾部取出數據。初始時，將迷宮的入口位置入隊，之後每次從隨機隊列中取出一個位置，並將與這個位置相鄰的四個方向入隊，循環至隊列爲空。

隨機隊列：

import java.util.LinkedList;

public class RandomQueue<E>{

    private LinkedList<E> queue;

    public RandomQueue(){
        queue = new LinkedList<E>();
    }

    public void add(E e){
        if(Math.random() < 0.5)
            queue.addFirst(e);
        else
            queue.addLast(e);
    }

    public E remove(){
        if(queue.size() == 0)
            throw new IllegalArgumentException("There's no element to remove in Random Qeuue");


        if(Math.random() < 0.5)
            return queue.removeFirst();
        else
            return queue.removeLast();
    }

    public int size(){
        return queue.size();
    }

    public boolean empty(){
        return size() == 0;
    }
}