Java实现飞机大战-II游戏详解

public class ShootGame extends JPanel {
    public static final int WIDTH = 400; // 面板宽
    public static final int HEIGHT = 654; // 面板高
    /**
     * 游戏的当前状态: START RUNNING PAUSE GAME_OVER
     */
    private int state;
    private static final int START = 0;
    private static final int RUNNING = 1;
    private static final int PAUSE = 2;
    private static final int GAME_OVER = 3;

    private int score = 0; // 得分
    private Timer timer; // 定时器
    private int intervel = 1000 / 100; // 时间间隔(毫秒)

    public static BufferedImage background;
    public static BufferedImage start;
    public static BufferedImage airplane;
    public static BufferedImage bee;
    public static BufferedImage bullet;
    public static BufferedImage hero0;
    public static BufferedImage hero1;
    public static BufferedImage pause;
    public static BufferedImage gameover;

    private FlyingObject[] flyings = {}; // 敌机数组
    private Bullet[] bullets = {}; // 子弹数组
    private Hero hero = new Hero(); // 英雄机

    static { // 静态代码块，初始化图片资源
        try {
            background = ImageIO.read(ShootGame.class
                    .getResource("background.png"));
            start = ImageIO.read(ShootGame.class.getResource("start.png"));
            airplane = ImageIO
                    .read(ShootGame.class.getResource("airplane.png"));
            bee = ImageIO.read(ShootGame.class.getResource("bee.png"));
            bullet = ImageIO.read(ShootGame.class.getResource("bullet.png"));
            hero0 = ImageIO.read(ShootGame.class.getResource("hero0.png"));
            hero1 = ImageIO.read(ShootGame.class.getResource("hero1.png"));
            pause = ImageIO.read(ShootGame.class.getResource("pause.png"));
            gameover = ImageIO
                    .read(ShootGame.class.getResource("gameover.png"));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 画
     */
    @Override
    public void paint(Graphics g) {
        g.drawImage(background, 0, 0, null); // 画背景图
        paintHero(g); // 画英雄机
        paintBullets(g); // 画子弹
        paintFlyingObjects(g); // 画飞行物
        paintScore(g); // 画分数
        paintState(g); // 画游戏状态
    }

    /**
     * 画英雄机
     */
    public void paintHero(Graphics g) {
        g.drawImage(hero.getImage(), hero.getX(), hero.getY(), null);
    }

    /**
     * 画子弹
     */
    public void paintBullets(Graphics g) {
        for (int i = 0; i < bullets.length; i++) {
            Bullet b = bullets[i];
            g.drawImage(b.getImage(), b.getX() - b.getWidth() / 2, b.getY(),
                    null);
        }
    }

    /**
     * 画飞行物
     */
    public void paintFlyingObjects(Graphics g) {
        for (int i = 0; i < flyings.length; i++) {
            FlyingObject f = flyings[i];
            g.drawImage(f.getImage(), f.getX(), f.getY(), null);
        }
    }

    /**
     * 画分数
     */
    public void paintScore(Graphics g) {
        int x = 10; // x坐标
        int y = 25; // y坐标
        Font font = new Font(Font.SANS_SERIF, Font.BOLD, 22); // 字体
        g.setColor(new Color(0xFF0000));
        g.setFont(font); // 设置字体
        g.drawString("SCORE:" + score, x, y); // 画分数
        y = y + 20; // y坐标增20
        g.drawString("LIFE:" + hero.getLife(), x, y); // 画命
    }

    /**
     * 画游戏状态
     */
    public void paintState(Graphics g) {
        switch (state) {
            case START: // 启动状态
                g.drawImage(start, 0, 0, null);
                break;
            case PAUSE: // 暂停状态
                g.drawImage(pause, 0, 0, null);
                break;
            case GAME_OVER: // 游戏终止状态
                g.drawImage(gameover, 0, 0, null);
                break;
        }
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Fly");
        ShootGame game = new ShootGame(); // 面板对象
        frame.add(game); // 将面板添加到JFrame中
        frame.setSize(WIDTH, HEIGHT); // 设置大小
        frame.setAlwaysOnTop(true); // 设置其总在最上
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // 默认关闭操作
        frame.setIconImage(new ImageIcon("images/icon.jpg").getImage()); // 设置窗体的图标
        frame.setLocationRelativeTo(null); // 设置窗体初始位置
        frame.setVisible(true); // 尽快调用paint

        game.action(); // 启动执行
    }

    /**
     * 启动执行代码
     */
    public void action() {
        // 鼠标监听事件
        MouseAdapter l = new MouseAdapter() {
            @Override
            public void mouseMoved(MouseEvent e) { // 鼠标移动
                if (state == RUNNING) { // 运行状态下移动英雄机--随鼠标位置
                    int x = e.getX();
                    int y = e.getY();
                    hero.moveTo(x, y);
                }
            }

            @Override
            public void mouseEntered(MouseEvent e) { // 鼠标进入
                if (state == PAUSE) { // 暂停状态下运行
                    state = RUNNING;
                }
            }

            @Override
            public void mouseExited(MouseEvent e) { // 鼠标退出
                if (state == RUNNING) { // 游戏未结束，则设置其为暂停
                    state = PAUSE;
                }
            }

            @Override
            public void mouseClicked(MouseEvent e) { // 鼠标点击
                switch (state) {
                    case START:
                        state = RUNNING; // 启动状态下运行
                        break;
                    case GAME_OVER: // 游戏结束，清理现场
                        flyings = new FlyingObject[0]; // 清空飞行物
                        bullets = new Bullet[0]; // 清空子弹
                        hero = new Hero(); // 重新创建英雄机
                        score = 0; // 清空成绩
                        state = START; // 状态设置为启动
                        break;
                }
            }
        };
        this.addMouseListener(l); // 处理鼠标点击操作
        this.addMouseMotionListener(l); // 处理鼠标滑动操作

        timer = new Timer(); // 主流程控制
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                if (state == RUNNING) { // 运行状态
                    enterAction(); // 飞行物入场
                    stepAction(); // 走一步
                    shootAction(); // 英雄机射击
                    bangAction(); // 子弹打飞行物
                    outOfBoundsAction(); // 删除越界飞行物及子弹
                    checkGameOverAction(); // 检查游戏结束
                }
                repaint(); // 重绘，调用paint()方法
            }

        }, intervel, intervel);
    }

    int flyEnteredIndex = 0; // 飞行物入场计数

    /**
     * 飞行物入场
     */
    public void enterAction() {
        flyEnteredIndex++;
        if (flyEnteredIndex % 40 == 0) { // 400毫秒生成一个飞行物--10*40
            FlyingObject obj = nextOne(); // 随机生成一个飞行物
            flyings = Arrays.copyOf(flyings, flyings.length + 1);
            flyings[flyings.length - 1] = obj;
        }
    }

    /**
     * 走一步
     */
    public void stepAction() {
        for (int i = 0; i < flyings.length; i++) { // 飞行物走一步
            FlyingObject f = flyings[i];
            f.step();
        }

        for (int i = 0; i < bullets.length; i++) { // 子弹走一步
            Bullet b = bullets[i];
            b.step();
        }
        hero.step(); // 英雄机走一步
    }

    /**
     * 飞行物走一步
     */
    public void flyingStepAction() {
        for (int i = 0; i < flyings.length; i++) {
            FlyingObject f = flyings[i];
            f.step();
        }
    }

    int shootIndex = 0; // 射击计数

    /**
     * 射击
     */
    public void shootAction() {
        shootIndex++;
        if (shootIndex % 30 == 0) { // 300毫秒发一颗
            Bullet[] bs = hero.shoot(); // 英雄打出子弹
            bullets = Arrays.copyOf(bullets, bullets.length + bs.length); // 扩容
            System.arraycopy(bs, 0, bullets, bullets.length - bs.length,
                    bs.length); // 追加数组
        }
    }

    /**
     * 子弹与飞行物碰撞检测
     */
    public void bangAction() {
        for (int i = 0; i < bullets.length; i++) { // 遍历所有子弹
            Bullet b = bullets[i];
            bang(b); // 子弹和飞行物之间的碰撞检查
        }
    }

    /**
     * 删除越界飞行物及子弹
     */
    public void outOfBoundsAction() {
        int index = 0; // 索引
        FlyingObject[] flyingLives = new FlyingObject[flyings.length]; // 活着的飞行物
        for (int i = 0; i < flyings.length; i++) {
            FlyingObject f = flyings[i];
            if (!f.outOfBounds()) {
                flyingLives[index++] = f; // 不越界的留着
            }
        }
        flyings = Arrays.copyOf(flyingLives, index); // 将不越界的飞行物都留着

        index = 0; // 索引重置为0
        Bullet[] bulletLives = new Bullet[bullets.length];
        for (int i = 0; i < bullets.length; i++) {
            Bullet b = bullets[i];
            if (!b.outOfBounds()) {
                bulletLives[index++] = b;
            }
        }
        bullets = Arrays.copyOf(bulletLives, index); // 将不越界的子弹留着
    }

    /**
     * 检查游戏结束
     */
    public void checkGameOverAction() {
        if (isGameOver() == true) {
            state = GAME_OVER; // 改变状态
        }
    }

    /**
     * 检查游戏是否结束
     */
    public boolean isGameOver() {

        for (int i = 0; i < flyings.length; i++) {
            int index = -1;
            FlyingObject obj = flyings[i];
            if (hero.hit(obj)) { // 检查英雄机与飞行物是否碰撞
                hero.subtractLife(); // 减命
                hero.setDoubleFire(0); // 双倍火力解除
                index = i; // 记录碰上的飞行物索引
            }
            if (index != -1) {
                FlyingObject t = flyings[index];
                flyings[index] = flyings[flyings.length - 1];
                flyings[flyings.length - 1] = t; // 碰上的与最后一个飞行物交换

                flyings = Arrays.copyOf(flyings, flyings.length - 1); // 删除碰上的飞行物
            }
        }

        return hero.getLife() <= 0;
    }

    /**
     * 子弹和飞行物之间的碰撞检查
     */
    public void bang(Bullet bullet) {
        int index = -1; // 击中的飞行物索引
        for (int i = 0; i < flyings.length; i++) {
            FlyingObject obj = flyings[i];
            if (obj.shootBy(bullet)) { // 判断是否击中
                index = i; // 记录被击中的飞行物的索引
                break;
            }
        }
        if (index != -1) { // 有击中的飞行物
            FlyingObject one = flyings[index]; // 记录被击中的飞行物

            FlyingObject temp = flyings[index]; // 被击中的飞行物与最后一个飞行物交换
            flyings[index] = flyings[flyings.length - 1];
            flyings[flyings.length - 1] = temp;

            flyings = Arrays.copyOf(flyings, flyings.length - 1); // 删除最后一个飞行物(即被击中的)

            // 检查one的类型(敌人加分，奖励获取)
            if (one instanceof Enemy) { // 检查类型，是敌人，则加分
                Enemy e = (Enemy) one; // 强制类型转换
                score += e.getScore(); // 加分
            } else { // 若为奖励，设置奖励
                Award a = (Award) one;
                int type = a.getType(); // 获取奖励类型
                switch (type) {
                    case Award.DOUBLE_FIRE:
                        hero.addDoubleFire(); // 设置双倍火力
                        break;
                    case Award.LIFE:
                        hero.addLife(); // 设置加命
                        break;
                }
            }
        }
    }

    /**
     * 随机生成飞行物
     *
     * @return 飞行物对象
     */
    public static FlyingObject nextOne() {
        Random random = new Random();
        int type = random.nextInt(20); // [0,20)
        if (type < 4) {
            return new Bee();
        } else {
            return new Airplane();
        }
    }

}

public class Hero extends FlyingObject{
	
	private BufferedImage[] images = {};  //英雄机图片
	private int index = 0;                //英雄机图片切换索引
	
	private int doubleFire;   //双倍火力
	private int life;   //命
	
	/** 初始化数据 */
	public Hero(){
		life = 3;   //初始3条命
		doubleFire = 0;   //初始火力为0
		images = new BufferedImage[]{ShootGame.hero0, ShootGame.hero1}; //英雄机图片数组
		image = ShootGame.hero0;   //初始为hero0图片
		width = image.getWidth();
		height = image.getHeight();
		x = 150;
		y = 400;
	}
	
	/** 获取双倍火力 */
	public int isDoubleFire() {
		return doubleFire;
	}

	/** 设置双倍火力 */
	public void setDoubleFire(int doubleFire) {
		this.doubleFire = doubleFire;
	}
	
	/** 增加火力 */
	public void addDoubleFire(){
		doubleFire = 40;
	}
	
	/** 增命 */
	public void addLife(){  //增命
		life++;
	}
	
	/** 减命 */
	public void subtractLife(){   //减命
		life--;
	}
	
	/** 获取命 */
	public int getLife(){
		return life;
	}
	
	/** 当前物体移动了一下，相对距离，x,y鼠标位置  */
	public void moveTo(int x,int y){   
		this.x = x - width/2;
		this.y = y - height/2;
	}

	/** 越界处理 */
	@Override
	public boolean outOfBounds() {
		return false;  
	}

	/** 发射子弹 */
	public Bullet[] shoot(){   
		int xStep = width/4;      //4半
		int yStep = 20;  //步
		if(doubleFire>0){  //双倍火力
			Bullet[] bullets = new Bullet[2];
			bullets[0] = new Bullet(x+xStep,y-yStep);  //y-yStep(子弹距飞机的位置)
			bullets[1] = new Bullet(x+3*xStep,y-yStep);
			return bullets;
		}else{      //单倍火力
			Bullet[] bullets = new Bullet[1];
			bullets[0] = new Bullet(x+2*xStep,y-yStep);  
			return bullets;
		}
	}

	/** 移动 */
	@Override
	public void step() {
		if(images.length>0){
			image = images[index++/10%images.length];  //切换图片hero0，hero1
		}
	}
	
	/** 碰撞算法 */
	public boolean hit(FlyingObject other){
		
		int x1 = other.x - this.width/2;                 //x坐标最小距离
		int x2 = other.x + this.width/2 + other.width;   //x坐标最大距离
		int y1 = other.y - this.height/2;                //y坐标最小距离
		int y2 = other.y + this.height/2 + other.height; //y坐标最大距离
	
		int herox = this.x + this.width/2;               //英雄机x坐标中心点距离
		int heroy = this.y + this.height/2;              //英雄机y坐标中心点距离
		
		return herox>x1 && herox<x2 && heroy>y1 && heroy<y2;   //区间范围内为撞上了
	}
	
}