Java 吃豆人 · ZetCode 中文系列教程

# Java 吃豆人 > 原文： [https://zetcode.com/tutorials/javagamestutorial/pacman/](https://zetcode.com/tutorials/javagamestutorial/pacman/) 在 Java 2D 游戲教程的這一部分中，我們將創建一個簡單的 Pacman 游戲克隆。 Pacman 是一款街機游戲，最初由日本公司 Namco 在 1980 年開發。Pacman 成為有史以來最受歡迎的街機游戲之一。 ## 開發以下代碼示例是 Brian Postma 對 Pacman 游戲的翻版，可從 [http://www.brianpostma.com](http://www.brianpostma.com/java.html) 獲得。修改并簡化了代碼，以便于理解。游戲的目標是收集迷宮中的所有點并避開鬼魂。吃豆人的動畫制作有兩種方式：在迷宮中的位置和身體。我們根據方向為他的身體制作四幅圖像。該動畫用于創建吃豆人張開和閉合嘴巴的幻覺。迷宮由`15x15`正方形組成。迷宮的結構基于簡單的整數數組。吃豆人有三命。我們還計算分數。游戲包含兩個文件：`Board.java`和`Pacman.java`。 `Board.java` ```java package com.zetcode; import java.awt.BasicStroke; import java.awt.Color; import java.awt.Dimension; import java.awt.Event; import java.awt.Font; import java.awt.FontMetrics; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Image; 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 javax.swing.ImageIcon; import javax.swing.JPanel; import javax.swing.Timer; public class Board extends JPanel implements ActionListener { private Dimension d; private final Font smallFont = new Font("Helvetica", Font.BOLD, 14); private Image ii; private final Color dotColor = new Color(192, 192, 0); private Color mazeColor; private boolean inGame = false; private boolean dying = false; private final int BLOCK_SIZE = 24; private final int N_BLOCKS = 15; private final int SCREEN_SIZE = N_BLOCKS * BLOCK_SIZE; private final int PAC_ANIM_DELAY = 2; private final int PACMAN_ANIM_COUNT = 4; private final int MAX_GHOSTS = 12; private final int PACMAN_SPEED = 6; private int pacAnimCount = PAC_ANIM_DELAY; private int pacAnimDir = 1; private int pacmanAnimPos = 0; private int N_GHOSTS = 6; private int pacsLeft, score; private int[] dx, dy; private int[] ghost_x, ghost_y, ghost_dx, ghost_dy, ghostSpeed; private Image ghost; private Image pacman1, pacman2up, pacman2left, pacman2right, pacman2down; private Image pacman3up, pacman3down, pacman3left, pacman3right; private Image pacman4up, pacman4down, pacman4left, pacman4right; private int pacman_x, pacman_y, pacmand_x, pacmand_y; private int req_dx, req_dy, view_dx, view_dy; private final short levelData[] = { 19, 26, 26, 26, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 22, 21, 0, 0, 0, 17, 16, 16, 16, 16, 16, 16, 16, 16, 16, 20, 21, 0, 0, 0, 17, 16, 16, 16, 16, 16, 16, 16, 16, 16, 20, 21, 0, 0, 0, 17, 16, 16, 24, 16, 16, 16, 16, 16, 16, 20, 17, 18, 18, 18, 16, 16, 20, 0, 17, 16, 16, 16, 16, 16, 20, 17, 16, 16, 16, 16, 16, 20, 0, 17, 16, 16, 16, 16, 24, 20, 25, 16, 16, 16, 24, 24, 28, 0, 25, 24, 24, 16, 20, 0, 21, 1, 17, 16, 20, 0, 0, 0, 0, 0, 0, 0, 17, 20, 0, 21, 1, 17, 16, 16, 18, 18, 22, 0, 19, 18, 18, 16, 20, 0, 21, 1, 17, 16, 16, 16, 16, 20, 0, 17, 16, 16, 16, 20, 0, 21, 1, 17, 16, 16, 16, 16, 20, 0, 17, 16, 16, 16, 20, 0, 21, 1, 17, 16, 16, 16, 16, 16, 18, 16, 16, 16, 16, 20, 0, 21, 1, 17, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 20, 0, 21, 1, 25, 24, 24, 24, 24, 24, 24, 24, 24, 16, 16, 16, 18, 20, 9, 8, 8, 8, 8, 8, 8, 8, 8, 8, 25, 24, 24, 24, 28 }; private final int validSpeeds[] = {1, 2, 3, 4, 6, 8}; private final int maxSpeed = 6; private int currentSpeed = 3; private short[] screenData; private Timer timer; public Board() { loadImages(); initVariables(); initBoard(); } private void initBoard() { addKeyListener(new TAdapter()); setFocusable(true); setBackground(Color.black); } private void initVariables() { screenData = new short[N_BLOCKS * N_BLOCKS]; mazeColor = new Color(5, 100, 5); d = new Dimension(400, 400); ghost_x = new int[MAX_GHOSTS]; ghost_dx = new int[MAX_GHOSTS]; ghost_y = new int[MAX_GHOSTS]; ghost_dy = new int[MAX_GHOSTS]; ghostSpeed = new int[MAX_GHOSTS]; dx = new int[4]; dy = new int[4]; timer = new Timer(40, this); timer.start(); } @Override public void addNotify() { super.addNotify(); initGame(); } private void doAnim() { pacAnimCount--; if (pacAnimCount <= 0) { pacAnimCount = PAC_ANIM_DELAY; pacmanAnimPos = pacmanAnimPos + pacAnimDir; if (pacmanAnimPos == (PACMAN_ANIM_COUNT - 1) || pacmanAnimPos == 0) { pacAnimDir = -pacAnimDir; } } } private void playGame(Graphics2D g2d) { if (dying) { death(); } else { movePacman(); drawPacman(g2d); moveGhosts(g2d); checkMaze(); } } private void showIntroScreen(Graphics2D g2d) { g2d.setColor(new Color(0, 32, 48)); g2d.fillRect(50, SCREEN_SIZE / 2 - 30, SCREEN_SIZE - 100, 50); g2d.setColor(Color.white); g2d.drawRect(50, SCREEN_SIZE / 2 - 30, SCREEN_SIZE - 100, 50); String s = "Press s to start."; Font small = new Font("Helvetica", Font.BOLD, 14); FontMetrics metr = this.getFontMetrics(small); g2d.setColor(Color.white); g2d.setFont(small); g2d.drawString(s, (SCREEN_SIZE - metr.stringWidth(s)) / 2, SCREEN_SIZE / 2); } private void drawScore(Graphics2D g) { int i; String s; g.setFont(smallFont); g.setColor(new Color(96, 128, 255)); s = "Score: " + score; g.drawString(s, SCREEN_SIZE / 2 + 96, SCREEN_SIZE + 16); for (i = 0; i < pacsLeft; i++) { g.drawImage(pacman3left, i * 28 + 8, SCREEN_SIZE + 1, this); } } private void checkMaze() { short i = 0; boolean finished = true; while (i < N_BLOCKS * N_BLOCKS && finished) { if ((screenData[i] & 48) != 0) { finished = false; } i++; } if (finished) { score += 50; if (N_GHOSTS < MAX_GHOSTS) { N_GHOSTS++; } if (currentSpeed < maxSpeed) { currentSpeed++; } initLevel(); } } private void death() { pacsLeft--; if (pacsLeft == 0) { inGame = false; } continueLevel(); } private void moveGhosts(Graphics2D g2d) { short i; int pos; int count; for (i = 0; i < N_GHOSTS; i++) { if (ghost_x[i] % BLOCK_SIZE == 0 && ghost_y[i] % BLOCK_SIZE == 0) { pos = ghost_x[i] / BLOCK_SIZE + N_BLOCKS * (int) (ghost_y[i] / BLOCK_SIZE); count = 0; if ((screenData[pos] & 1) == 0 && ghost_dx[i] != 1) { dx[count] = -1; dy[count] = 0; count++; } if ((screenData[pos] & 2) == 0 && ghost_dy[i] != 1) { dx[count] = 0; dy[count] = -1; count++; } if ((screenData[pos] & 4) == 0 && ghost_dx[i] != -1) { dx[count] = 1; dy[count] = 0; count++; } if ((screenData[pos] & 8) == 0 && ghost_dy[i] != -1) { dx[count] = 0; dy[count] = 1; count++; } if (count == 0) { if ((screenData[pos] & 15) == 15) { ghost_dx[i] = 0; ghost_dy[i] = 0; } else { ghost_dx[i] = -ghost_dx[i]; ghost_dy[i] = -ghost_dy[i]; } } else { count = (int) (Math.random() * count); if (count > 3) { count = 3; } ghost_dx[i] = dx[count]; ghost_dy[i] = dy[count]; } } ghost_x[i] = ghost_x[i] + (ghost_dx[i] * ghostSpeed[i]); ghost_y[i] = ghost_y[i] + (ghost_dy[i] * ghostSpeed[i]); drawGhost(g2d, ghost_x[i] + 1, ghost_y[i] + 1); if (pacman_x > (ghost_x[i] - 12) && pacman_x < (ghost_x[i] + 12) && pacman_y > (ghost_y[i] - 12) && pacman_y < (ghost_y[i] + 12) && inGame) { dying = true; } } } private void drawGhost(Graphics2D g2d, int x, int y) { g2d.drawImage(ghost, x, y, this); } private void movePacman() { int pos; short ch; if (req_dx == -pacmand_x && req_dy == -pacmand_y) { pacmand_x = req_dx; pacmand_y = req_dy; view_dx = pacmand_x; view_dy = pacmand_y; } if (pacman_x % BLOCK_SIZE == 0 && pacman_y % BLOCK_SIZE == 0) { pos = pacman_x / BLOCK_SIZE + N_BLOCKS * (int) (pacman_y / BLOCK_SIZE); ch = screenData[pos]; if ((ch & 16) != 0) { screenData[pos] = (short) (ch & 15); score++; } if (req_dx != 0 || req_dy != 0) { if (!((req_dx == -1 && req_dy == 0 && (ch & 1) != 0) || (req_dx == 1 && req_dy == 0 && (ch & 4) != 0) || (req_dx == 0 && req_dy == -1 && (ch & 2) != 0) || (req_dx == 0 && req_dy == 1 && (ch & 8) != 0))) { pacmand_x = req_dx; pacmand_y = req_dy; view_dx = pacmand_x; view_dy = pacmand_y; } } // Check for standstill if ((pacmand_x == -1 && pacmand_y == 0 && (ch & 1) != 0) || (pacmand_x == 1 && pacmand_y == 0 && (ch & 4) != 0) || (pacmand_x == 0 && pacmand_y == -1 && (ch & 2) != 0) || (pacmand_x == 0 && pacmand_y == 1 && (ch & 8) != 0)) { pacmand_x = 0; pacmand_y = 0; } } pacman_x = pacman_x + PACMAN_SPEED * pacmand_x; pacman_y = pacman_y + PACMAN_SPEED * pacmand_y; } private void drawPacman(Graphics2D g2d) { if (view_dx == -1) { drawPacnanLeft(g2d); } else if (view_dx == 1) { drawPacmanRight(g2d); } else if (view_dy == -1) { drawPacmanUp(g2d); } else { drawPacmanDown(g2d); } } private void drawPacmanUp(Graphics2D g2d) { switch (pacmanAnimPos) { case 1: g2d.drawImage(pacman2up, pacman_x + 1, pacman_y + 1, this); break; case 2: g2d.drawImage(pacman3up, pacman_x + 1, pacman_y + 1, this); break; case 3: g2d.drawImage(pacman4up, pacman_x + 1, pacman_y + 1, this); break; default: g2d.drawImage(pacman1, pacman_x + 1, pacman_y + 1, this); break; } } private void drawPacmanDown(Graphics2D g2d) { switch (pacmanAnimPos) { case 1: g2d.drawImage(pacman2down, pacman_x + 1, pacman_y + 1, this); break; case 2: g2d.drawImage(pacman3down, pacman_x + 1, pacman_y + 1, this); break; case 3: g2d.drawImage(pacman4down, pacman_x + 1, pacman_y + 1, this); break; default: g2d.drawImage(pacman1, pacman_x + 1, pacman_y + 1, this); break; } } private void drawPacnanLeft(Graphics2D g2d) { switch (pacmanAnimPos) { case 1: g2d.drawImage(pacman2left, pacman_x + 1, pacman_y + 1, this); break; case 2: g2d.drawImage(pacman3left, pacman_x + 1, pacman_y + 1, this); break; case 3: g2d.drawImage(pacman4left, pacman_x + 1, pacman_y + 1, this); break; default: g2d.drawImage(pacman1, pacman_x + 1, pacman_y + 1, this); break; } } private void drawPacmanRight(Graphics2D g2d) { switch (pacmanAnimPos) { case 1: g2d.drawImage(pacman2right, pacman_x + 1, pacman_y + 1, this); break; case 2: g2d.drawImage(pacman3right, pacman_x + 1, pacman_y + 1, this); break; case 3: g2d.drawImage(pacman4right, pacman_x + 1, pacman_y + 1, this); break; default: g2d.drawImage(pacman1, pacman_x + 1, pacman_y + 1, this); break; } } private void drawMaze(Graphics2D g2d) { short i = 0; int x, y; for (y = 0; y < SCREEN_SIZE; y += BLOCK_SIZE) { for (x = 0; x < SCREEN_SIZE; x += BLOCK_SIZE) { g2d.setColor(mazeColor); g2d.setStroke(new BasicStroke(2)); if ((screenData[i] & 1) != 0) { g2d.drawLine(x, y, x, y + BLOCK_SIZE - 1); } if ((screenData[i] & 2) != 0) { g2d.drawLine(x, y, x + BLOCK_SIZE - 1, y); } if ((screenData[i] & 4) != 0) { g2d.drawLine(x + BLOCK_SIZE - 1, y, x + BLOCK_SIZE - 1, y + BLOCK_SIZE - 1); } if ((screenData[i] & 8) != 0) { g2d.drawLine(x, y + BLOCK_SIZE - 1, x + BLOCK_SIZE - 1, y + BLOCK_SIZE - 1); } if ((screenData[i] & 16) != 0) { g2d.setColor(dotColor); g2d.fillRect(x + 11, y + 11, 2, 2); } i++; } } } private void initGame() { pacsLeft = 3; score = 0; initLevel(); N_GHOSTS = 6; currentSpeed = 3; } private void initLevel() { int i; for (i = 0; i < N_BLOCKS * N_BLOCKS; i++) { screenData[i] = levelData[i]; } continueLevel(); } private void continueLevel() { short i; int dx = 1; int random; for (i = 0; i < N_GHOSTS; i++) { ghost_y[i] = 4 * BLOCK_SIZE; ghost_x[i] = 4 * BLOCK_SIZE; ghost_dy[i] = 0; ghost_dx[i] = dx; dx = -dx; random = (int) (Math.random() * (currentSpeed + 1)); if (random > currentSpeed) { random = currentSpeed; } ghostSpeed[i] = validSpeeds[random]; } pacman_x = 7 * BLOCK_SIZE; pacman_y = 11 * BLOCK_SIZE; pacmand_x = 0; pacmand_y = 0; req_dx = 0; req_dy = 0; view_dx = -1; view_dy = 0; dying = false; } private void loadImages() { ghost = new ImageIcon("images/ghost.png").getImage(); pacman1 = new ImageIcon("images/pacman.png").getImage(); pacman2up = new ImageIcon("images/up1.png").getImage(); pacman3up = new ImageIcon("images/up2.png").getImage(); pacman4up = new ImageIcon("images/up3.png").getImage(); pacman2down = new ImageIcon("images/down1.png").getImage(); pacman3down = new ImageIcon("images/down2.png").getImage(); pacman4down = new ImageIcon("images/down3.png").getImage(); pacman2left = new ImageIcon("images/left1.png").getImage(); pacman3left = new ImageIcon("images/left2.png").getImage(); pacman4left = new ImageIcon("images/left3.png").getImage(); pacman2right = new ImageIcon("images/right1.png").getImage(); pacman3right = new ImageIcon("images/right2.png").getImage(); pacman4right = new ImageIcon("images/right3.png").getImage(); } @Override public void paintComponent(Graphics g) { super.paintComponent(g); doDrawing(g); } private void doDrawing(Graphics g) { Graphics2D g2d = (Graphics2D) g; g2d.setColor(Color.black); g2d.fillRect(0, 0, d.width, d.height); drawMaze(g2d); drawScore(g2d); doAnim(); if (inGame) { playGame(g2d); } else { showIntroScreen(g2d); } g2d.drawImage(ii, 5, 5, this); Toolkit.getDefaultToolkit().sync(); g2d.dispose(); } class TAdapter extends KeyAdapter { @Override public void keyPressed(KeyEvent e) { int key = e.getKeyCode(); if (inGame) { if (key == KeyEvent.VK_LEFT) { req_dx = -1; req_dy = 0; } else if (key == KeyEvent.VK_RIGHT) { req_dx = 1; req_dy = 0; } else if (key == KeyEvent.VK_UP) { req_dx = 0; req_dy = -1; } else if (key == KeyEvent.VK_DOWN) { req_dx = 0; req_dy = 1; } else if (key == KeyEvent.VK_ESCAPE && timer.isRunning()) { inGame = false; } else if (key == KeyEvent.VK_PAUSE) { if (timer.isRunning()) { timer.stop(); } else { timer.start(); } } } else { if (key == 's' || key == 'S') { inGame = true; initGame(); } } } @Override public void keyReleased(KeyEvent e) { int key = e.getKeyCode(); if (key == Event.LEFT || key == Event.RIGHT || key == Event.UP || key == Event.DOWN) { req_dx = 0; req_dy = 0; } } } @Override public void actionPerformed(ActionEvent e) { repaint(); } } ``` 用光標鍵控制吃豆人。 `Esc` 鍵完成游戲，`暫停`鍵暫停游戲。 ```java private int pacman_x, pacman_y, pacmand_x, pacmand_y; ``` 前兩個變量存儲吃豆子精靈的 x 和 y 坐標。最后兩個變量是水平和垂直方向的增量變化。 ```java private final short levelData[] = { 19, 26, 26, 26, 18, 18, 18, 18, ... }; ``` 這些數字組成了迷宮。它們提供了信息，我們可以據此創建角點。 1 號是左上角。數字 2、4 和 8 分別代表頂角，右角和底角。 16 號是重點。可以添加這些數字，例如左上角的數字 19 表示正方形將具有頂部和左側邊框以及一個點（`16 + 2 + 1`）。 ```java private void doAnim() { pacAnimCount--; if (pacAnimCount <= 0) { pacAnimCount = PAC_ANIM_DELAY; pacmanAnimPos = pacmanAnimPos + pacAnimDir; if (pacmanAnimPos == (PACMAN_ANIM_COUNT - 1) || pacmanAnimPos == 0) { pacAnimDir = -pacAnimDir; } } } ``` `doAnim()`對`pacmanAnimPos`變量進行計數，該變量確定繪制哪種吃豆子圖像。有四個吃豆人圖像。還有一個`PAC_ANIM_DELAY`常數，它會使動畫變慢。否則，吃豆人會太快張開嘴。 ```java boolean finished = true; while (i < N_BLOCKS * N_BLOCKS && finished) { if ((screenData[i] & 48) != 0) { finished = false; } i++; } ``` 此代碼是`checkMaze()`方法的一部分。它檢查吃豆人是否還有剩余的食物要吃。數字 16 代表一個點。如果所有積分都被消耗掉了，我們將進入下一個層次。（在我們的例子中，我們只是重新啟動游戲。）接下來，我們將研究`moveGhosts()`方法。鬼魂移動一個正方形，然后決定是否改變方向。 ```java if (ghost_x[i] % BLOCK_SIZE == 0 && ghost_y[i] % BLOCK_SIZE == 0) { ``` 我們僅在完成移動一個正方形后才繼續。 ```java pos = pacman_x / BLOCK_SIZE + N_BLOCKS * (int) (pacman_y / BLOCK_SIZE); ``` 這條線確定了幻影的位置；在哪個位置/正方形。有 225 個理論職位。（鬼不能在墻上移動。） ```java if ((screenData[pos] & 1) == 0 && ghost_dx[i] != 1) { dx[count] = -1; dy[count] = 0; count++; } ``` 如果左側沒有障礙物并且幻影尚未向右移動，則幻影將向左移動。該代碼的真正含義是什么？如果幽靈進入隧道，他將朝著同一方向繼續前進，直到他離開隧道。鬼影的移動部分是隨機的。我們不會在長隧道中應用這種隨機性，因為幽靈可能會卡在那里。 ```java if (pacman_x > (ghost_x[i] - 12) && pacman_x < (ghost_x[i] + 12) && pacman_y > (ghost_y[i] - 12) && pacman_y < (ghost_y[i] + 12) && inGame) { dying = true; } ``` 如果幽靈和吃豆人之間發生碰撞，吃豆人會死。接下來，我們將研究`movePacman()`方法。 `req_dx`和`req_dy`變量在`TAdapter`內部類中確定。這些變量由光標鍵控制。 ```java if ((ch & 16) != 0) { screenData[pos] = (short) (ch & 15); score++; } ``` 如果吃豆人移動到帶點的位置，我們將其從迷宮中移出并增加得分值。 ```java if ((pacmand_x == -1 && pacmand_y == 0 && (ch & 1) != 0) || (pacmand_x == 1 && pacmand_y == 0 && (ch & 4) != 0) || (pacmand_x == 0 && pacmand_y == -1 && (ch & 2) != 0) || (pacmand_x == 0 && pacmand_y == 1 && (ch & 8) != 0)) { pacmand_x = 0; pacmand_y = 0; } ``` 如果吃豆子無法按當前方向繼續前進，則會停下來。 ```java private void drawPacman(Graphics2D g2d) { if (view_dx == -1) { drawPacnanLeft(g2d); } else if (view_dx == 1) { drawPacmanRight(g2d); } else if (view_dy == -1) { drawPacmanUp(g2d); } else { drawPacmanDown(g2d); } } ``` 吃豆人有四個可能的方向。所有方向都有四個圖像。這些圖像用于為吃豆人張嘴和閉嘴動畫。 `drawMaze()`方法從`screenData`數組中的數字中提取迷宮。數字 1 是左側邊框，2 是頂部邊框，4 是右側邊框，8 是底部邊框，16 是點。我們只需在迷宮中瀏覽所有 225 平方。例如，在`screenData`數組中有 9 個。我們設置了第一位（1）和第四位（8）。因此，我們在此特定正方形上繪制了底部和左側邊框。 ```java if ((screenData[i] & 1) != 0) { g2d.drawLine(x, y, x, y + BLOCK_SIZE - 1); } ``` 如果設置了數字的第一位，我們將繪制左邊框。 `Pacman.java` ```java package com.zetcode; import java.awt.EventQueue; import javax.swing.JFrame; public class Pacman extends JFrame { public Pacman() { initUI(); } private void initUI() { add(new Board()); setTitle("Pacman"); setDefaultCloseOperation(EXIT_ON_CLOSE); setSize(380, 420); setLocationRelativeTo(null); } public static void main(String[] args) { EventQueue.invokeLater(() -> { Pacman ex = new Pacman(); ex.setVisible(true); }); } } ``` 這是帶有`main`方法的 Pacman 文件。 ![Pacman](https://img.kancloud.cn/fa/73/fa73b77bf6d0f4381205c4e13ffd6b62_380x420.jpg) 圖：吃豆人這是吃豆子游戲。