sharkprey.java

鲨鱼攻击猎物游戏 是一个Applet程序

package shark;

import java.awt.*;

/**
 * 猎物类，实现猎物的显示、移动、以及判断是否被鲨鱼吃掉等功能
 */
public class SharkPrey {
    private SharkAttack applet = null;

    private Image animal = null; //猎物的图片

    private Rectangle bounds = new Rectangle();

    private int deltaX, amp; //位移和振幅

    public SharkPrey(Image _animal, SharkAttack _applet) {
        animal = _animal;
        applet = _applet;
        deltaX = (int) (2 * Math.random()) + 1;
        amp = (int) (55 * Math.random()) + 10;
        bounds.x = (int) (applet.getSize().width * Math.random());
        bounds.y = 120 + (int) (amp * Math.sin(bounds.x / 20.0));
        bounds.height = animal.getHeight(null);
        bounds.width = animal.getWidth(null);
    }

    /**
     * 猎物的移动路线是简单的正弦曲线(振幅是随机的)，初始位置随机产生。
     */
    public void move() {
        if ((bounds.x > applet.getSize().width) || (bounds.x < 0)) {
            deltaX *= (-1);
        }
        bounds.x += deltaX;
        bounds.y = 120 + (int) (amp * Math.sin(bounds.x / 20.0));
    }

    /**
     * @param shark
     * @return 如果获得的鲨鱼鱼鳍顶点坐标值在猎物所在的矩形区域内，则猎物被吃掉，返回值为true，否则为false
     */
    public boolean isEatenBy(Shark shark) {
        return bounds.contains(shark.getTip());
    }

    public void paintComponent(Graphics g) {
        g.drawImage(animal, bounds.x, bounds.y, null);
    }
}