Java 俄罗斯方块
最后修改于 2023 年 1 月 10 日
在本部分的 Java 2D 游戏教程中，我们将创建一个简单的俄罗斯方块游戏克隆。源代码和图片可以在作者的 Github Java-Space-Invaders 仓库中找到。
俄罗斯方块 是由Tomohiro Nishikado设计的街机视频游戏。它于1978年首次发布。
在俄罗斯方块游戏中，玩家控制一个炮塔。他即将从邪恶的太空入侵者手中拯救地球。
用 Java 开发俄罗斯方块
在我们的 Java 克隆版中，我们有 24 个入侵者。这些外星人会猛烈炮击地面。当玩家发射导弹时，只有在导弹击中外星人或棋盘顶部后才能发射下一枚。玩家用空格键射击。外星人随机发射炸弹。每个外星人仅在前一个炸弹击中地面后才发射炸弹。
com/zetcode/SpaceInvaders.java
package com.zetcode;
import java.awt.EventQueue;
import javax.swing.JFrame;
public class SpaceInvaders extends JFrame {
public SpaceInvaders() {
initUI();
}
private void initUI() {
add(new Board());
setTitle("Space Invaders");
setSize(Commons.BOARD_WIDTH, Commons.BOARD_HEIGHT);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setResizable(false);
setLocationRelativeTo(null);
}
public static void main(String[] args) {
EventQueue.invokeLater(() -> {
var ex = new SpaceInvaders();
ex.setVisible(true);
});
}
}
这是主类。它负责设置应用程序。
com/zetcode/Commons.java
package com.zetcode;
public interface Commons {
int BOARD_WIDTH = 358;
int BOARD_HEIGHT = 350;
int BORDER_RIGHT = 30;
int BORDER_LEFT = 5;
int GROUND = 290;
int BOMB_HEIGHT = 5;
int ALIEN_HEIGHT = 12;
int ALIEN_WIDTH = 12;
int ALIEN_INIT_X = 150;
int ALIEN_INIT_Y = 5;
int GO_DOWN = 15;
int NUMBER_OF_ALIENS_TO_DESTROY = 24;
int CHANCE = 5;
int DELAY = 17;
int PLAYER_WIDTH = 15;
int PLAYER_HEIGHT = 10;
}
Commons.java 文件包含一些公共常量。它们不言自明。
com/zetcode/sprite/Alien.java
package com.zetcode.sprite;
import javax.swing.ImageIcon;
public class Alien extends Sprite {
private Bomb bomb;
public Alien(int x, int y) {
initAlien(x, y);
}
private void initAlien(int x, int y) {
this.x = x;
this.y = y;
bomb = new Bomb(x, y);
var alienImg = "src/images/alien.png";
var ii = new ImageIcon(alienImg);
setImage(ii.getImage());
}
public void act(int direction) {
this.x += direction;
}
public Bomb getBomb() {
return bomb;
}
public class Bomb extends Sprite {
private boolean destroyed;
public Bomb(int x, int y) {
initBomb(x, y);
}
private void initBomb(int x, int y) {
setDestroyed(true);
this.x = x;
this.y = y;
var bombImg = "src/images/bomb.png";
var ii = new ImageIcon(bombImg);
setImage(ii.getImage());
}
public void setDestroyed(boolean destroyed) {
this.destroyed = destroyed;
}
public boolean isDestroyed() {
return destroyed;
}
}
}
这是 Alien 精灵。每个外星人都有一个内部的 Bomb 类。
public void act(int direction) {
this.x += direction;
}
act() 方法由 Board 类调用。它用于在水平方向上定位外星人。
public Bomb getBomb() {
return bomb;
}
当外星人即将投下炸弹时，会调用 getBomb() 方法。
com/zetcode/sprite/Player.java
package com.zetcode.sprite;
import com.zetcode.Commons;
import javax.swing.ImageIcon;
import java.awt.event.KeyEvent;
public class Player extends Sprite {
private int width;
public Player() {
initPlayer();
}
private void initPlayer() {
var playerImg = "src/images/player.png";
var ii = new ImageIcon(playerImg);
width = ii.getImage().getWidth(null);
setImage(ii.getImage());
int START_X = 270;
setX(START_X);
int START_Y = 280;
setY(START_Y);
}
public void act() {
x += dx;
if (x <= 2) {
x = 2;
}
if (x >= Commons.BOARD_WIDTH - 2 * width) {
x = Commons.BOARD_WIDTH - 2 * width;
}
}
public void keyPressed(KeyEvent e) {
int key = e.getKeyCode();
if (key == KeyEvent.VK_LEFT) {
dx = -2;
}
if (key == KeyEvent.VK_RIGHT) {
dx = 2;
}
}
public void keyReleased(KeyEvent e) {
int key = e.getKeyCode();
if (key == KeyEvent.VK_LEFT) {
dx = 0;
}
if (key == KeyEvent.VK_RIGHT) {
dx = 0;
}
}
}
这是 Player 精灵。我们用光标键控制炮塔。
int START_X = 270; setX(START_X); int START_Y = 280; setY(START_Y);
这些是玩家精灵的初始坐标。
public void keyPressed(KeyEvent e) {
int key = e.getKeyCode();
if (key == KeyEvent.VK_LEFT) {
dx = -2;
}
...
如果我们按下左光标键，dx 变量将设置为 -2。下次调用 act() 方法时，玩家将向左移动。
public void keyReleased(KeyEvent e) {
int key = e.getKeyCode();
if (key == KeyEvent.VK_LEFT) {
dx = 0;
}
if (key == KeyEvent.VK_RIGHT) {
dx = 0;
}
}
如果我们释放左或右光标键，dx 变量将设置为零。玩家精灵停止移动。
com/zetcode/sprite/Shot.java
package com.zetcode.sprite;
import javax.swing.ImageIcon;
public class Shot extends Sprite {
public Shot() {
}
public Shot(int x, int y) {
initShot(x, y);
}
private void initShot(int x, int y) {
var shotImg = "src/images/shot.png";
var ii = new ImageIcon(shotImg);
setImage(ii.getImage());
int H_SPACE = 6;
setX(x + H_SPACE);
int V_SPACE = 1;
setY(y - V_SPACE);
}
}
这是 Shot 精灵。射击由 空格键 触发。H_SPACE 和 V_SPACE 常量用于适当的定位导弹。
com/zetcode/sprite/Sprite.java
package com.zetcode.sprite;
import java.awt.Image;
public class Sprite {
private boolean visible;
private Image image;
private boolean dying;
int x;
int y;
int dx;
public Sprite() {
visible = true;
}
public void die() {
visible = false;
}
public boolean isVisible() {
return visible;
}
protected void setVisible(boolean visible) {
this.visible = visible;
}
public void setImage(Image image) {
this.image = image;
}
public Image getImage() {
return image;
}
public void setX(int x) {
this.x = x;
}
public void setY(int y) {
this.y = y;
}
public int getY() {
return y;
}
public int getX() {
return x;
}
public void setDying(boolean dying) {
this.dying = dying;
}
public boolean isDying() {
return this.dying;
}
}
这是基础的 Sprite 类。其他精灵继承自它。它包含一些通用功能。
com/zetcode/Board.java
package com.zetcode;
import com.zetcode.sprite.Alien;
import com.zetcode.sprite.Player;
import com.zetcode.sprite.Shot;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.Timer;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
public class Board extends JPanel {
private Dimension d;
private List<Alien> aliens;
private Player player;
private Shot shot;
private int direction = -1;
private int deaths = 0;
private boolean inGame = true;
private String explImg = "src/images/explosion.png";
private String message = "Game Over";
private Timer timer;
public Board() {
initBoard();
gameInit();
}
private void initBoard() {
addKeyListener(new TAdapter());
setFocusable(true);
d = new Dimension(Commons.BOARD_WIDTH, Commons.BOARD_HEIGHT);
setBackground(Color.black);
timer = new Timer(Commons.DELAY, new GameCycle());
timer.start();
gameInit();
}
private void gameInit() {
aliens = new ArrayList<>();
for (int i = 0; i < 4; i++) {
for (int j = 0; j < 6; j++) {
var alien = new Alien(Commons.ALIEN_INIT_X + 18 * j,
Commons.ALIEN_INIT_Y + 18 * i);
aliens.add(alien);
}
}
player = new Player();
shot = new Shot();
}
private void drawAliens(Graphics g) {
for (Alien alien : aliens) {
if (alien.isVisible()) {
g.drawImage(alien.getImage(), alien.getX(), alien.getY(), this);
}
if (alien.isDying()) {
alien.die();
}
}
}
private void drawPlayer(Graphics g) {
if (player.isVisible()) {
g.drawImage(player.getImage(), player.getX(), player.getY(), this);
}
if (player.isDying()) {
player.die();
inGame = false;
}
}
private void drawShot(Graphics g) {
if (shot.isVisible()) {
g.drawImage(shot.getImage(), shot.getX(), shot.getY(), this);
}
}
private void drawBombing(Graphics g) {
for (Alien a : aliens) {
Alien.Bomb b = a.getBomb();
if (!b.isDestroyed()) {
g.drawImage(b.getImage(), b.getX(), b.getY(), this);
}
}
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
doDrawing(g);
}
private void doDrawing(Graphics g) {
g.setColor(Color.black);
g.fillRect(0, 0, d.width, d.height);
g.setColor(Color.green);
if (inGame) {
g.drawLine(0, Commons.GROUND,
Commons.BOARD_WIDTH, Commons.GROUND);
drawAliens(g);
drawPlayer(g);
drawShot(g);
drawBombing(g);
} else {
if (timer.isRunning()) {
timer.stop();
}
gameOver(g);
}
Toolkit.getDefaultToolkit().sync();
}
private void gameOver(Graphics g) {
g.setColor(Color.black);
g.fillRect(0, 0, Commons.BOARD_WIDTH, Commons.BOARD_HEIGHT);
g.setColor(new Color(0, 32, 48));
g.fillRect(50, Commons.BOARD_WIDTH / 2 - 30, Commons.BOARD_WIDTH - 100, 50);
g.setColor(Color.white);
g.drawRect(50, Commons.BOARD_WIDTH / 2 - 30, Commons.BOARD_WIDTH - 100, 50);
var small = new Font("Helvetica", Font.BOLD, 14);
var fontMetrics = this.getFontMetrics(small);
g.setColor(Color.white);
g.setFont(small);
g.drawString(message, (Commons.BOARD_WIDTH - fontMetrics.stringWidth(message)) / 2,
Commons.BOARD_WIDTH / 2);
}
private void update() {
if (deaths == Commons.NUMBER_OF_ALIENS_TO_DESTROY) {
inGame = false;
timer.stop();
message = "Game won!";
}
// player
player.act();
// shot
if (shot.isVisible()) {
int shotX = shot.getX();
int shotY = shot.getY();
for (Alien alien : aliens) {
int alienX = alien.getX();
int alienY = alien.getY();
if (alien.isVisible() && shot.isVisible()) {
if (shotX >= (alienX)
&& shotX <= (alienX + Commons.ALIEN_WIDTH)
&& shotY >= (alienY)
&& shotY <= (alienY + Commons.ALIEN_HEIGHT)) {
var ii = new ImageIcon(explImg);
alien.setImage(ii.getImage());
alien.setDying(true);
deaths++;
shot.die();
}
}
}
int y = shot.getY();
y -= 4;
if (y < 0) {
shot.die();
} else {
shot.setY(y);
}
}
// aliens
for (Alien alien : aliens) {
int x = alien.getX();
if (x >= Commons.BOARD_WIDTH - Commons.BORDER_RIGHT && direction != -1) {
direction = -1;
Iterator<Alien> i1 = aliens.iterator();
while (i1.hasNext()) {
Alien a2 = i1.next();
a2.setY(a2.getY() + Commons.GO_DOWN);
}
}
if (x <= Commons.BORDER_LEFT && direction != 1) {
direction = 1;
Iterator<Alien> i2 = aliens.iterator();
while (i2.hasNext()) {
Alien a = i2.next();
a.setY(a.getY() + Commons.GO_DOWN);
}
}
}
Iterator<Alien> it = aliens.iterator();
while (it.hasNext()) {
Alien alien = it.next();
if (alien.isVisible()) {
int y = alien.getY();
if (y > Commons.GROUND - Commons.ALIEN_HEIGHT) {
inGame = false;
message = "Invasion!";
}
alien.act(direction);
}
}
// bombs
var generator = new Random();
for (Alien alien : aliens) {
int shot = generator.nextInt(15);
Alien.Bomb bomb = alien.getBomb();
if (shot == Commons.CHANCE && alien.isVisible() && bomb.isDestroyed()) {
bomb.setDestroyed(false);
bomb.setX(alien.getX());
bomb.setY(alien.getY());
}
int bombX = bomb.getX();
int bombY = bomb.getY();
int playerX = player.getX();
int playerY = player.getY();
if (player.isVisible() && !bomb.isDestroyed()) {
if (bombX >= (playerX)
&& bombX <= (playerX + Commons.PLAYER_WIDTH)
&;& bombY >= (playerY)
&& bombY <= (playerY + Commons.PLAYER_HEIGHT)) {
var ii = new ImageIcon(explImg);
player.setImage(ii.getImage());
player.setDying(true);
bomb.setDestroyed(true);
}
}
if (!bomb.isDestroyed()) {
bomb.setY(bomb.getY() + 1);
if (bomb.getY() >= Commons.GROUND - Commons.BOMB_HEIGHT) {
bomb.setDestroyed(true);
}
}
}
}
private void doGameCycle() {
update();
repaint();
}
private class GameCycle implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
doGameCycle();
}
}
private class TAdapter extends KeyAdapter {
@Override
public void keyReleased(KeyEvent e) {
player.keyReleased(e);
}
@Override
public void keyPressed(KeyEvent e) {
player.keyPressed(e);
int x = player.getX();
int y = player.getY();
int key = e.getKeyCode();
if (key == KeyEvent.VK_SPACE) {
if (inGame) {
if (!shot.isVisible()) {
shot = new Shot(x, y);
}
}
}
}
}
}
游戏的主要逻辑位于 Board 类中。
private void gameInit() {
aliens = new ArrayList<>();
for (int i = 0; i < 4; i++) {
for (int j = 0; j < 6; j++) {
var alien = new Alien(Commons.ALIEN_INIT_X + 18 * j,
Commons.ALIEN_INIT_Y + 18 * i);
aliens.add(alien);
}
}
player = new Player();
shot = new Shot();
}
在 gameInit() 方法中，我们创建了 24 个外星人。外星人图像大小为 12x12 像素。我们在外星人之间留有 6 像素的间距。我们还创建了玩家和射击对象。
private void drawBombing(Graphics g) {
for (Alien a : aliens) {
Alien.Bomb b = a.getBomb();
if (!b.isDestroyed()) {
g.drawImage(b.getImage(), b.getX(), b.getY(), this);
}
}
}
drawBombing() 方法绘制外星人发射的炸弹。
if (inGame) {
g.drawLine(0, Commons.GROUND,
Commons.BOARD_WIDTH, Commons.GROUND);
drawAliens(g);
drawPlayer(g);
drawShot(g);
drawBombing(g);
} ...
在 doDrawing() 方法中，我们绘制地面、外星人、玩家、射击和炸弹。
private void update() {
if (deaths == Commons.NUMBER_OF_ALIENS_TO_DESTROY) {
inGame = false;
timer.stop();
message = "Game won!";
}
...
在 update() 方法中，我们检查被摧毁外星人的数量。如果我们摧毁了所有外星人，我们就赢得了游戏。
if (alien.isVisible() && shot.isVisible()) {
if (shotX >= (alienX)
&& shotX <= (alienX + Commons.ALIEN_WIDTH)
&& shotY >= (alienY)
&& shotY <= (alienY + Commons.ALIEN_HEIGHT)) {
var ii = new ImageIcon(explImg);
alien.setImage(ii.getImage());
alien.setDying(true);
deaths++;
shot.die();
}
}
如果玩家触发的射击与外星人发生碰撞，则外星飞船被摧毁。更准确地说，会设置死亡标志。我们用它来显示爆炸。deaths 变量增加，射击精灵被销毁。
if (x >= Commons.BOARD_WIDTH - Commons.BORDER_RIGHT && direction != -1) {
direction = -1;
Iterator<Alien> i1 = aliens.iterator();
while (i1.hasNext()) {
Alien a2 = i1.next();
a2.setY(a2.getY() + Commons.GO_DOWN);
}
}
如果外星人到达棋盘的右边缘，它们会向下移动并改变方向向左。
Iterator<Alien> it = aliens.iterator();
while (it.hasNext()) {
Alien alien = it.next();
if (alien.isVisible()) {
int y = alien.getY();
if (y > Commons.GROUND - Commons.ALIEN_HEIGHT) {
inGame = false;
message = "Invasion!";
}
alien.act(direction);
}
}
这段代码移动外星人。如果它们到达底部，入侵就开始了。
int shot = generator.nextInt(15);
Alien.Bomb bomb = alien.getBomb();
if (shot == Commons.CHANCE && alien.isVisible() && bomb.isDestroyed()) {
bomb.setDestroyed(false);
bomb.setX(alien.getX());
bomb.setY(alien.getY());
}
这段代码决定外星人是否会投下炸弹。外星人不得被摧毁；也就是说，它必须是可见的。炸弹的 destroyed 标志必须被设置。换句话说，这是外星人第一次投弹，或者之前投下的炸弹已经击中地面。如果满足这两个条件，则投弹就交给机会。
if (!bomb.isDestroyed()) {
bomb.setY(bomb.getY() + 1);
if (bomb.getY() >= Commons.GROUND - Commons.BOMB_HEIGHT) {
bomb.setDestroyed(true);
}
}
如果炸弹未被摧毁，它将向下移动 1 像素。如果它击中地面，则设置 destroyed 标志。外星人现在已准备好投下另一枚炸弹。
public void keyReleased(KeyEvent e) {
player.keyReleased(e);
}
该特定 KeyEvent 的实际处理被委托给玩家精灵。
在本部分的 Java 游戏教程中，我们创建了俄罗斯方块。