java 游戏编程 (五)

交互性
前面已经完成了全屏幕，全屏幕下的动画与全屏幕下的动画移动。下面来看交互性问题。用键盘控制Fly的移动。Fly类见上一篇。在这之前先写一个辅助类，CoreSupport。这个类主要完成显示设置和运动动画loop，在开发的类可以再这个类的基础之上，直接继承这个类。

/**
 * 
 */
package com.jsheng.game.util;

import java.awt.Color;
import java.awt.DisplayMode;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Window;

import javax.swing.ImageIcon;

/** function:
 * company: jsheng
 * @author wanghn      [e-mail]
 */
public abstract class CoreSupport {
	protected static final int FONT_SIZE = 24;

    private static final DisplayMode POSSIBLE_MODES[] = {
        new DisplayMode(800, 600, 32, 0),
        new DisplayMode(800, 600, 24, 0),
        new DisplayMode(800, 600, 16, 0),
        new DisplayMode(640, 480, 32, 0),
        new DisplayMode(640, 480, 24, 0),
        new DisplayMode(640, 480, 16, 0)
    };
    private boolean isRunning;
    protected MyScreenMgr screen;
    public void stop() {
        isRunning = false;
    }
    
    public void run() {
        try {
            init();
            gameLoop();
        }
        finally {
            screen.reScreen();
        }
    }
    public void init() {
        screen = new MyScreenMgr();
        DisplayMode displayMode =
            screen.findFirstCompatibleMode(POSSIBLE_MODES);
        screen.setFullScreen(displayMode);

        Window window = screen.getFullScreenWindow();
        window.setFont(new Font("Dialog", Font.PLAIN, FONT_SIZE));
        window.setBackground(Color.black);
        window.setForeground(Color.white);

        isRunning = true;
    }
    public Image loadImage(String fileName) {
        return new ImageIcon(fileName).getImage();
    }
    public void gameLoop() {
        long startTime = System.currentTimeMillis();
        long currTime = startTime;

        while (isRunning) {
            long elapsedTime =
                System.currentTimeMillis() - currTime;
            currTime += elapsedTime;
            update(elapsedTime);
            Graphics2D g = screen.getGraphics();
            draw(g);
            g.dispose();
            screen.update();
            try {
                Thread.sleep(20);
            }
            catch (InterruptedException ex) { }
        }
    } 
    public void update(long elapsedTime) {
       
    }
    public abstract void draw(Graphics2D g);
}

其中的init方法初始化图片和变量
update方法在子类中实现
draw方法由子类完成

下面完成用户操作，用ESC退出程序，并能显示按下的键盘按键

package com.jsheng.game.test1;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Window;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.LinkedList;

import com.jsheng.game.util.CoreSupport;
import com.jsheng.game.util.GameCore;

/** function:
 * company: jsheng
 * @author wanghn      [e-mail]
 */
public class KeyTest extends CoreSupport implements KeyListener {

    public static void main(String[] args) {
        new KeyTest().run();
    }

    private LinkedList<String> messages = new LinkedList<String>();

    public void init() {
    	super.init();

        Window window = screen.getFullScreenWindow();
        window.setFocusTraversalKeysEnabled(false);
        window.addKeyListener(this);
        addMessage("键盘测试，按下ESC退出");
    }

    public void keyPressed(KeyEvent e) {
        int keyCode = e.getKeyCode();

        if (keyCode == KeyEvent.VK_ESCAPE) {
             stop();
        }
        else {
            addMessage("Pressed: " +
                KeyEvent.getKeyText(keyCode));
        }
    }

    public void keyReleased(KeyEvent e) {
        int keyCode = e.getKeyCode();
        addMessage("Released: " + KeyEvent.getKeyText(keyCode));
    }


    public void keyTyped(KeyEvent e) {
    }
    public synchronized void addMessage(String message) {
        messages.add(message);
        if (messages.size() >= screen.getHeight() / FONT_SIZE) {
            messages.remove(0);
        }
    }
    public synchronized void draw(Graphics2D g) {

        Window window = screen.getFullScreenWindow();
        g.setRenderingHint(
            RenderingHints.KEY_TEXT_ANTIALIASING,
            RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
        g.setColor(window.getBackground());
        g.fillRect(0, 0, screen.getWidth(), screen.getHeight());
        g.setColor(window.getForeground());
        int y = FONT_SIZE;
        for (int i=0; i<messages.size(); i++) {
            g.drawString(messages.get(i), 5, y);
            y+=FONT_SIZE;
        }
    }
}