Snake/Java
< Snake
Code
<lang java>import java.awt.*; import java.awt.event.*; import static java.lang.String.format; import java.util.*; import java.util.List; import javax.swing.*;
public class Snake extends JPanel implements Runnable {
enum Dir { up(0, -1), right(1, 0), down(0, 1), left(-1, 0);
Dir(int x, int y) { xy = new int[]{x, y}; }
final int[] xy; };
static final Random rand = new Random(); static final int WALL = -1; static final int MAX_ENERGY = 1500;
volatile boolean gameOver = true;
Thread gameThread; int score, hiScore; int nRows = 44; int nCols = 64; Dir dir; int energy;
int[][] grid; List<Point> snake, treats; Font smallFont;
public Snake() { setPreferredSize(new Dimension(640, 440)); setBackground(Color.white); setFont(new Font("SansSerif", Font.BOLD, 48)); setFocusable(true);
smallFont = getFont().deriveFont(Font.BOLD, 18); initGrid();
addMouseListener(new MouseAdapter() { @Override public void mousePressed(MouseEvent e) { if (gameOver) { startNewGame(); repaint(); } } });
addKeyListener(new KeyAdapter() {
@Override public void keyPressed(KeyEvent e) {
switch (e.getKeyCode()) {
case KeyEvent.VK_UP: if (dir != Dir.down) dir = Dir.up; break;
case KeyEvent.VK_LEFT: if (dir != Dir.right) dir = Dir.left; break;
case KeyEvent.VK_RIGHT: if (dir != Dir.left) dir = Dir.right; break;
case KeyEvent.VK_DOWN: if (dir != Dir.up) dir = Dir.down; break; } repaint(); } }); }
void startNewGame() { gameOver = false;
stop(); initGrid(); treats = new LinkedList<>();
dir = Dir.left; energy = MAX_ENERGY;
if (score > hiScore) hiScore = score; score = 0;
snake = new ArrayList<>(); for (int x = 0; x < 7; x++) snake.add(new Point(nCols / 2 + x, nRows / 2));
(gameThread = new Thread(this)).start(); }
void stop() { if (gameThread != null) { Thread tmp = gameThread; gameThread = null; tmp.interrupt(); } }
void initGrid() { grid = new int[nRows][nCols]; for (int r = 0; r < nRows; r++) { for (int c = 0; c < nCols; c++) { if (c == 0 || c == nCols - 1 || r == 0 || r == nRows - 1) grid[r][c] = WALL; } } }
@Override public void run() {
while (Thread.currentThread() == gameThread) {
try { Thread.sleep(Math.max(75 - score, 25)); } catch (InterruptedException e) { return; }
if (energyUsed() || hitsWall() || hitsSnake()) { gameOver(); } else { if (eatsTreat()) { score++; energy = MAX_ENERGY; growSnake(); } moveSnake(); addTreat(); } repaint(); } }
boolean energyUsed() { energy -= 10; return energy <= 0; }
boolean hitsWall() { Point head = snake.get(0); int nextCol = head.x + dir.xy[0]; int nextRow = head.y + dir.xy[1]; return grid[nextRow][nextCol] == WALL; }
boolean hitsSnake() { Point head = snake.get(0); int nextCol = head.x + dir.xy[0]; int nextRow = head.y + dir.xy[1]; for (Point p : snake) if (p.x == nextCol && p.y == nextRow) return true; return false; }
boolean eatsTreat() { Point head = snake.get(0); int nextCol = head.x + dir.xy[0]; int nextRow = head.y + dir.xy[1]; for (Point p : treats) if (p.x == nextCol && p.y == nextRow) { return treats.remove(p); } return false; }
void gameOver() { gameOver = true; stop(); }
void moveSnake() { for (int i = snake.size() - 1; i > 0; i--) { Point p1 = snake.get(i - 1); Point p2 = snake.get(i); p2.x = p1.x; p2.y = p1.y; } Point head = snake.get(0); head.x += dir.xy[0]; head.y += dir.xy[1]; }
void growSnake() { Point tail = snake.get(snake.size() - 1); int x = tail.x + dir.xy[0]; int y = tail.y + dir.xy[1]; snake.add(new Point(x, y)); }
void addTreat() { if (treats.size() < 3) {
if (rand.nextInt(10) == 0) { // 1 in 10
if (rand.nextInt(4) != 0) { // 3 in 4 int x, y; while (true) {
x = rand.nextInt(nCols); y = rand.nextInt(nRows); if (grid[y][x] != 0) continue;
Point p = new Point(x, y); if (snake.contains(p) || treats.contains(p)) continue;
treats.add(p); break; } } else if (treats.size() > 1) treats.remove(0); } } }
void drawGrid(Graphics2D g) { g.setColor(Color.lightGray); for (int r = 0; r < nRows; r++) { for (int c = 0; c < nCols; c++) { if (grid[r][c] == WALL) g.fillRect(c * 10, r * 10, 10, 10); } } }
void drawSnake(Graphics2D g) { g.setColor(Color.blue); for (Point p : snake) g.fillRect(p.x * 10, p.y * 10, 10, 10);
g.setColor(energy < 500 ? Color.red : Color.orange); Point head = snake.get(0); g.fillRect(head.x * 10, head.y * 10, 10, 10); }
void drawTreats(Graphics2D g) { g.setColor(Color.green); for (Point p : treats) g.fillRect(p.x * 10, p.y * 10, 10, 10); }
void drawStartScreen(Graphics2D g) { g.setColor(Color.blue); g.setFont(getFont()); g.drawString("Snake", 240, 190); g.setColor(Color.orange); g.setFont(smallFont); g.drawString("(click to start)", 250, 240); }
void drawScore(Graphics2D g) { int h = getHeight(); g.setFont(smallFont); g.setColor(getForeground()); String s = format("hiscore %d score %d", hiScore, score); g.drawString(s, 30, h - 30); g.drawString(format("energy %d", energy), getWidth() - 150, h - 30); }
@Override public void paintComponent(Graphics gg) { super.paintComponent(gg); Graphics2D g = (Graphics2D) gg; g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
drawGrid(g);
if (gameOver) { drawStartScreen(g); } else { drawSnake(g); drawTreats(g); drawScore(g); } }
public static void main(String[] args) { SwingUtilities.invokeLater(() -> { JFrame f = new JFrame(); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setTitle("Snake"); f.setResizable(false); f.add(new Snake(), BorderLayout.CENTER); f.pack(); f.setLocationRelativeTo(null); f.setVisible(true); }); }
}</lang>