/*
   Copyright F. P. Marin ( April 07 13:12:53 1998 )
   E-mail: felix@bloch.ciens.ucv.ve
   
   Permission to use, copy, modify and distribute this software and its
   documentation for NON-COMERCIAL purposes and without fee is hereby
   granted provided that this copyright notice appears in all copies.

   F. P. Marin makes no representations or warranties about the suitability
   of the software, either express or implied, including but no limited to
   the implied warranties of merchantability, fitness for a particular
   purpose, or non-infringement. F. P. Marin shall not be liable for any
   damage suffered by license as a result of using, modifying or
   distributing this software or its derivatives.

   HTML code is

   <applet archive="Abstract.jar"
              code="Abstract.class"
            height=400
             width=400>
   <param name=delay   value="10">
   <param name=npoints value="100">
   </applet>
*/
import java.awt.Graphics;
import java.awt.Color;


public class Abstract extends java.applet.Applet implements Runnable
{
       final double PHASE=Math.PI/180.0;
       final double COSP=Math.cos(PHASE),SINP=Math.sin(PHASE);
       Color c[];
       double cmx,cmz,x[],y[],z[];
       int delay=42,I,xcenter,intx[],inty[];
       Thread rota=null;


       public void init()
       {
        int i;
        String s=getParameter("npoints");

        setBackground(Color.blue);
        setForeground(Color.yellow);
        if ( s!=null ) x=new double[Integer.parseInt(s)];
                  else x=new double[16];
        s=getParameter("delay");
        if ( s!=null ) delay=Integer.parseInt(s);
        y=new double[x.length];
        z=new double[x.length];
        intx=new int[x.length + 1];
        inty=new int[intx.length];
        c=new Color[11];
         c[0]=new Color(0,0,0);
         c[1]=new Color(0,255,255);
         c[2]=new Color(64,64,64);
         c[3]=new Color(128,128,128);
         c[4]=new Color(0,255,0);
         c[5]=new Color(192,192,192);
         c[6]=new Color(255,0,255);
         c[7]=new Color(255,200,0);
         c[8]=new Color(255,175,175);
         c[9]=new Color(255,0,0);
        c[10]=new Color(255,255,0);
        int dx=(int)Math.floor(0.6*size().width + 0.5);
        int dy=(int)Math.floor(0.6*size().height + 0.5);
        int dz=(int)Math.floor(0.5*(dx + dy + 1)); 
        xcenter=size().width/2;
        double cmy=0.0;
        for ( i=0 ; i<x.length ; ++i ) {
            x[i]=dx*Math.random();
            y[i]=dy*Math.random();
            cmy+=y[i];
            z[i]=dz*Math.random();
        }
        cmy=cmy/x.length - size().height/2.0;
        for ( i=0 ; i<y.length ; ++i ) {
            y[i]-=cmy;
            inty[i]=(int)Math.floor(y[i] + 0.5);
        }
        inty[i]=inty[0];
        move_ToCenter();
       }


       public void run()
       {
        double temp;
        int i;
         
        while ( true ) {
              repaint();
              try { Thread.sleep(delay); }
              catch (InterruptedException e) {}
              for ( i=0 ; i<x.length ; ++i ) {
                  temp=x[i];
                  x[i]=x[i]*COSP - z[i]*SINP;
                  z[i]=temp*SINP + z[i]*COSP;
              }
              move_ToCenter();
        }
       }


       public void start()
       {
        if ( rota==null ) {
           rota=new Thread(this);
           rota.start();
        }
       }


       public void stop()
       {
        if ( rota!=null ) {
           rota.stop();
           rota=null;
        }
       }
       
       
       public void move_ToCenter()
       {
        cmx=cmz=0.0;
        for ( I=0 ; I<x.length ; ++I ) {
            cmx+=x[I];
            cmz+=z[I];
        }
        cmx=cmx/x.length - xcenter;
        cmz/=x.length;
        for ( I=0 ; I<x.length ; ++I ) {
            x[I]-=cmx;
            intx[I]=(int)Math.floor(x[I] + 0.5);
            z[I]-=cmz;
        }
        intx[I]=intx[0];
       }

 
       public void paint(Graphics g)
       {
        g.setColor(getForeground());
        g.drawPolygon(intx,inty,intx.length);
        int j=0;
        for ( int i=0 ; i<x.length ; ++i ) {
            g.setColor(c[j++]);
            g.fillOval(intx[i] - 3,inty[i] - 3,6,6);
            if ( j==c.length ) j=0;
        }
       }
}