LACS03_Ball.java

//Ball.java MrG 2012.0531
import java.awt.Color;
public class Ball
{
    private double rx;
    private double ry;
    private double vx;
    private double vy;
    private double r;
    private Color c;

    public Ball()
    {
        int sign = Math.random()<0.5 ? -1 : 1;
        rx=0.0;
        ry=0.0;
        vx=sign*Math.random()/5;
        vy=sign*Math.random()/5;
        r=Math.random()/2;
        //c=Color.getHSBColor((float)Math.random(),0.8f,0.8f);
        c=new Color((float)Math.random(),(float)Math.random(),(float)Math.random());
    }

    public void draw()
    {
        StdDraw.setPenColor(c);
        StdDraw.filledCircle(rx,ry,r);
    }

    public void move()
    {
        if(Math.abs(rx+vx)>10){vx=-vx;}
        if(Math.abs(ry+vy)>10){vy=-vy;}
        rx+=vx;
        ry+=vy;
    }
}