高琪java300集案例源码，太阳系模型

package cn.bjsxt.solar; import java.awt.Color; import java.awt.Graphics; import java.awt.Image; import cn.bjsxt.util.GameUtil; public class Planet extends Star { //除了图片，坐标。 行星沿着某个椭圆运行：长轴、短轴、速度、角度。 绕着某个Star飞。 double longAxis; //椭圆的长轴 double shortAxis; //椭圆的短轴 double speed; //飞行的速度 double degree; Star center; boolean satellite; public void draw(Graphics g){ super.draw(g); move(); if(!satellite){ drawTrace(g); } } public void drawTrace(Graphics g){ double ovalX,ovalY,ovalWidth,ovalHeight; ovalWidth = longAxis*2; ovalHeight = shortAxis*2; ovalX = (center.x+center.width/2)-longAxis; ovalY = (center.y+center.height/2)-shortAxis; Color c =g.getColor(); g.setColor(Color.blue); g.drawOval((int)ovalX, (int)ovalY, (int)ovalWidth, (int)ovalHeight); g.setColor(c); } public void move(){ //沿着椭圆轨迹飞行 x = (center.x+center.width/2) + longAxis*Math.cos(degree); y = (center.y+center.height/2)+ shortAxis*Math.sin(degree); degree += speed; } public Planet(Star center,String imgpath, double longAxis, double shortAxis, double speed) { super(GameUtil.getImage(imgpath)); this.center = center; this.x = center.x + longAxis; this.y = center.y; this.longAxis = longAxis; this.shortAxis = shortAxis; this.speed = speed; this.width = img.getWidth(null); this.height = img.getHeight(null); } public Planet(Star center,String imgpath, double longAxis, double shortAxis, double speed,boolean satellite) { this(center, imgpath, longAxis, shortAxis, speed); this.satellite = satellite; } public Planet(Image img, double x, double y) { super(img, x, y); } public Planet(String imgpath, double x, double y) { super(imgpath, x, y); } }