AP计算机科学A(APcomputer science A)复习备考攻略视频教程
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如何设计出贪吃蛇游戏?
本次教程我们最主要的学习目的是设计出贪吃蛇游戏,大家可以根据这个学习目标,进行对课程的理解。
学习目标:
1.开发出贪吃蛇游戏
2.阅读并理解贪吃蛇游戏代码
3.参考贪吃蛇游戏,自己开发出类似的游戏
一.贪吃蛇游戏开发
1.新建一个项目GameFrame,再创建一个主类GameFrame
代码如下:
import java.awt.*;
import java.awt.event.*;
public class GameFrame {
public GameFrame() {
Frame app = new Frame("GameFrame");
app.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
app.setLocation(100, 100);
GamePanel drawB = new GamePanel();
app.add(drawB, BorderLayout.CENTER);
app.pack();
app.setResizable(false);
app.setVisible(true);
drawB.gameStart();
}
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
new GameFrame();
// TODO code application logic here
}
}
2.创建一个类GamePanel,代码如下:
import java.awt.*;
import java.awt.event.*;
/**
*
* @author Administrator
*/
public class GamePanel extends Panel implements Runnable, KeyListener{
public int width;
public int heigth;
public int incre=1;
private Image im;
private Graphics dbg;
private Thread gamethread;
private static final int FPS = 30;
private boolean running = false;
private boolean isPaused = false;
private int direction;
public static final int SOUTH = 0;
public static final int NORTH = 1;
public static final int EAST = 2;
public static final int WEST = 3;
private Snake sk;
private Food bk;
public GamePanel() {
width = 300;
heigth = 300;
setPreferredSize(new Dimension(width, heigth));
sk = new Snake(this);
bk = new Food(this, sk);
setFocusable(true);
requestFocus();
addKeyListener(this);
}
public int getDirection() {
return direction;
}
public void gameStart() {
if (!running) {
gamethread = new Thread(this);
gamethread.start();
}
}
public void gameStop() {
running = false;
}
public void gamePaint() {
Graphics g;
try {
g = this.getGraphics();
if (g != null && im != null) {
g.drawImage(im, 0, 0, null);
}
g.dispose();
} catch (Exception e) {
}
}
public void gameRender() {
if (im == null) {
im = createImage(width, heigth);
if (im == null) {
System.out.println("im is null");
} else {
dbg = im.getGraphics();
}
}
dbg.setColor(Color.white);
dbg.fillRect(0, 0, width, heigth);
sk.draw(dbg);
bk.draw(dbg);
}
public void gameUpdate() {
if (!isPaused) {
sk.update();
bk.update();
}
}
public void run() {
long t1,t2,dt,sleepTime;
long period=1000/FPS; //计算每一次循环需要的执行时间,单位毫秒
t1=System.nanoTime(); //保存游戏循环执行前的系统时间,单位纳秒
while(true){
gameUpdate();
gameRender();
gamePaint();
t2= System.nanoTime() ; //游戏循环执行后的系统时间,单位纳秒
dt=(t2-t1)/1000000L; //本次循环实际花费的时间,并转换为毫秒
sleepTime = period - dt;//计算本次循环剩余的时间,单位毫秒
if(sleepTime<=0) //防止sleepTime值为负数
sleepTime=2;
try {
Thread.sleep(sleepTime); //让线程休眠,由sleepTime值决定
} catch (InterruptedException ex) { }
t1 = System.nanoTime(); //重新获取当前系统时间
}
}
public void keyTyped(KeyEvent e) {
}
public void keyPressed(KeyEvent e) {
int keycode = e.getKeyCode();
if (keycode == KeyEvent.VK_P) {
isPaused = !isPaused;
System.out.println("key is P");
}
if (!isPaused ) {
switch (keycode) {
case KeyEvent.VK_DOWN:
direction = SOUTH;
System.out.println("key is down" + direction);
break;
case KeyEvent.VK_UP:
direction = NORTH;
System.out.println("key is up" + direction);
break;
case KeyEvent.VK_RIGHT:
direction = EAST;
System.out.println("key is right" + direction);
break;
case KeyEvent.VK_LEFT:
direction = WEST;
System.out.println("key is left" + direction);
break;
}
}
}
public void keyReleased(KeyEvent e) {
}
}
3.创建类:Food,代码如下:
import java.awt.*;
import java.util.Random;
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
/**
*
* @author new
*/
public class Food {
public Point location;
public Point size;
private GamePanel gameP;
private Snake snk;
private Random rand;
public Food(GamePanel gp, Snake sk) {
gameP = gp;
snk = sk;
rand = new Random();
location = new Point(Math.abs(rand.nextInt() % gameP.width), Math.abs(rand.nextInt() % gameP.heigth));
size = new Point(sk.diameter, sk.diameter);
}
public void update() {
if ((Math.abs((snk.x + snk.diameter / 2) - (location.x + size.x / 2)) < snk.diameter) &&
(Math.abs((snk.y + snk.diameter / 2) - (location.y + size.y / 2)) < snk.diameter)) {
location = new Point(Math.abs(rand.nextInt() % gameP.width), Math.abs(rand.nextInt() % gameP.heigth));
if (snk.length < Snake.MAXLENTH) {
snk.length++;
}
}
}
public void draw(Graphics g) {
g.setColor(Color.black);
g.fillRect(location.x, location.y, size.x, size.y);
}
}
4.创建类Snake,代码如下:
import java.awt.*;
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
/**
*
* @author new
*/
public class Snake {
GamePanel gameP;
private Point[] body;
public static final int MAXLENTH = 20;
private int head;
private int tail;
public int length;
private int speed;
public int x;
public int y;
public int diameter;
public Snake(GamePanel gp) {
gameP = gp;
body = new Point[MAXLENTH];
head = -1;
tail = -1;
length = 1;
speed = 3;
x = 50;
y = 50;
diameter = 10;
}
public void update() {
int direction=gameP.getDirection();
switch (direction) {
case GamePanel.SOUTH:
y += speed;
break;
case GamePanel.NORTH:
y -= speed;
break;
case GamePanel.EAST:
x += speed;
break;
case GamePanel.WEST:
x -= speed;
break;
}
if (x > gameP.width) {
x = -diameter;
}
if (y > gameP.heigth) {
y = -diameter;
}
if (x < -diameter) {
x = gameP.width;
}
if (y < -diameter) {
y = gameP.heigth;
}
head = (head + 1) % body.length;
tail = (head + body.length - length + 1) % body.length;
body[head] = new Point(x, y);
}
public void draw(Graphics g) {
g.setColor(Color.blue);
if (length > 1) {
int i = tail;
while (i != head) {
g.fillRect(body[i].x, body[i].y, diameter, diameter);
i = (i + 1) % body.length;
}
}
g.setColor(Color. blue);
g.fillRect(body[head].x, body[head].y, diameter, diameter);
}
}
保存全部,运行,试玩一下游戏,并自行理解代码.
小编结语:其实,这个游戏的java代码并不难,最主要是大家能够好好熟悉一下游戏框架,并在此框架上,自行设计自己喜欢的游戏。