// $AISD_VERSION:NumDemo.java@1.2/home/coei/arc/archive%shell3.ba.best.com$

//COPYRIGHT: Copyright (c) 1997 by Christopher K. Oei, Incorporated.
//COPYRIGHT: 
//COPYRIGHT: http://www.chrisoei.com
//COPYRIGHT: info@chrisoei.com
//COPYRIGHT: 
//COPYRIGHT: Permission to use, display, and modify this code
//COPYRIGHT: is hereby granted provided that:
//COPYRIGHT: 
//COPYRIGHT: 1) this notice is included in its entirety
//COPYRIGHT: 2) we are notified of the usage


import java.applet.*;
import java.awt.Graphics;
import java.awt.*;
import RKDemo;
import Rectangle;
import Line;

public class lev_mag extends Applet 
{
    int width=100; // the real width is 200
    int height=100; // the real height is 200
    int offsetx=50;
    int offsety=50;
    static int sig = -1;    //Initial sign value

    double x1 = 350.0;
    double y1 = 30;
    double ysum;
    int go = 0;

    double tim = 0;
    double dtim=0.001;

    public double[] x;
    public double[][] values;
    public double[][] graph;

    static double qvalue = 0;
    static double betavalue = 18.;

    static double ystat = 400.;

    int maxtim = 1;
    int brectcx;
    int brectcy;

    double dist1;
    double dist2;
    double distt;
    double dists;
    double compx, compx1, compx2;
    double compy, compy1, compy2;
    double dummy = 0.;
    double rada = 100.;

    int x2 = 325;
    int y2 = 240;

    int numline = 2;

    int si = 0;
    int ki = 0;
    int max = 24;
    int sii = 0;
    int iv;
    double xolder;

    Scrollbar timeScroll = new Scrollbar(Scrollbar.HORIZONTAL,maxtim,1,1,10),betaScroll = new Scrollbar(Scrollbar.HORIZONTAL,(int)betavalue,1,3,50),qvalueScroll = new Scrollbar(Scrollbar.HORIZONTAL,(int)qvalue,1,0,100);

    public Label qvalueLabel = new Label("Friction = " + qvalue), betaLabel = new Label("Speed =  " +betavalue), timeLabel = new Label("T = " +maxtim);

  Button restartbutton = new Button("Restart"), gobutton = new Button("Go");
    Button signbutton = new Button("Flip Top Magnet");

public void init()
    {

    restartbutton.setForeground(Color.black);
    restartbutton.setBackground(Color.lightGray);

    signbutton.setForeground(Color.black);
    signbutton.setBackground(Color.lightGray);

    gobutton.setForeground(Color.black);
    gobutton.setBackground(Color.lightGray);

    timeScroll.setForeground(Color.black);
    timeScroll.setBackground(Color.lightGray);

    betaScroll.setForeground(Color.black);
    betaScroll.setBackground(Color.lightGray);

    qvalueScroll.setForeground(Color.black);
    qvalueScroll.setBackground(Color.lightGray);

    
    setLayout(new BorderLayout());

    Panel p = new Panel();
    p.setLayout(new FlowLayout(FlowLayout.CENTER));
    p.add(gobutton);
    p.add(restartbutton);
    p.add(signbutton);

    add("North",p);

    Panel t = new Panel();
    t.setLayout(new FlowLayout(FlowLayout.CENTER));

    t.add(betaScroll);
    t.add(betaLabel);

    t.add(timeScroll);
    t.add(timeLabel);

    t.add(qvalueScroll);
    t.add(qvalueLabel);

    add("South",t);

    }

public void Reset()
    {
	x1 = 350.0;
	y1 = 30;
	go = 0;
	tim = 0;
	repaint();
    }

public void Settvalue(String m)
    {
  	maxtim = new Integer(m).intValue();
    }

public void Setqvalue(String m)
    {
	qvalue = new Double(m).doubleValue();
    }

public void Setbvalue(String m)
    {
	betavalue = new Double(m).doubleValue();
    }

public void SetGo()
    {
	go = 1;
	repaint();
    }
 
public void paint(Graphics g)
    {
	setBackground(java.awt.Color.white);
	
//      double values[] = {21.5,25.,30.};
//      double values[] = {15.5,20.,25.};
        double values[][] = { {15.5,20.,25.}, {12.5,19.,26.} };
    
        x = new double[3];
        graph = new double[2][(max+1)];

	x[0]=3;
	x[1]=0;
	x[2]=0;

        double[] xold=new double[3];

	xold[0]=x[0];
	xold[1]=x[1]; 
	xold[2]=x[2];

	Rectangle rect = new Rectangle(15,35,(int)x1,(int)y1);
	RKDemo nint=new RKDemo(tim,x,.01);
	Line line=new Line(0.0,0.0,0.0,0.0);


	if(tim==0 && go==1)
	    {
		while(tim<maxtim && rect.cy < 550)
		   {    
    			line.emag = 1;

			rect.cx = (int)x1;
			rect.cy = (int)y1;

//   draw magnet as it falls, as well as stationary ring

			y1 = 30+(70*(3-xold[0]));
                        ysum=ystat+y1;

			g.setColor(java.awt.Color.white);
    			g.drawLine(rect.cx-rect.rw,rect.cy-rect.rh+2,rect.cx-rect.rw,rect.cy+rect.rh+2);
			g.drawOval(rect.cx-rect.rw,rect.cy-rect.rh,(2*rect.rw),4);
    			g.drawLine(rect.cx+rect.rw,rect.cy-rect.rh+2,rect.cx+rect.rw,rect.cy+rect.rh+2);
			g.drawOval(rect.cx-rect.rw,rect.cy+rect.rh,(2*rect.rw),4);

			g.setColor(java.awt.Color.black);

    			g.drawLine(rect.cx-rect.rw,rect.cy-rect.rh+2,rect.cx-rect.rw,rect.cy+rect.rh+2);
			g.drawOval(rect.cx-rect.rw,rect.cy-rect.rh,(2*rect.rw),4);
    			g.drawLine(rect.cx+rect.rw,rect.cy-rect.rh+2,rect.cx+rect.rw,rect.cy+rect.rh+2);
			g.drawOval(rect.cx-rect.rw,rect.cy+rect.rh,(2*rect.rw),4);

// 	g.drawRect(25,350,450,100);

// draw the three field lines from falling magnet

            iv=0;
    	    while(iv < 3)
         	{
                    if(sig<0)
                      {
	    	       line.ang = values[1][iv]*(Math.PI/180.);
                      }
                    else
                      {
	    	       line.ang = values[0][iv]*(Math.PI/180.);
                      }


        	    line.sx = x1 - 5 * Math.sin(line.ang);
        	    line.sy = y1 - 5 * Math.cos(line.ang);

                    distt=100.;
                    dists=100.;

        	    double delarc = betavalue;
                    double intarc;
                    int ij;
                    double output1,output2;
                    intarc = delarc/3.;

                    ij = 0;
		    si = 0;

//   draw field lines from falling magnet, at three different angles

             	    while(ij < 100  && distt > 30.0 && dists > 30.0)
//             	    while(ij < 50  && distt > 30.0 )
                	{


                	    dist1 = Math.sqrt(Math.pow(line.sx-x1, 2) + Math.pow(line.sy - y1, 2));
                	    dists = Math.sqrt(Math.pow(line.sx-x1, 2) + Math.pow(line.sy - ystat, 2));
                          if (ij > 5)
                             {
                              distt=dist1;
                             }
                          else
                             {
                             distt=100.;
                             }
  
  
 			//compute components of dipole field of falling magnet

                	    compx1 = (3.*(line.sx-x1)*(line.sy-y1)/4.*Math.PI)/Math.pow(Math.pow(line.sx-x1,2)+Math.pow(line.sy-y1,2),2.5) ;
                	    compy1 = ((2.*Math.pow(line.sy-y1,2)-Math.pow(line.sx-x1,2))/4.*Math.PI)/Math.pow(Math.pow(line.sx-x1,2) + Math.pow(line.sy-y1,2),2.5);

 			//compute components of dipole field of stationary magnet

                	    compx2 = (3.*(line.sx-x1)*(line.sy-ystat)/4.*Math.PI)/Math.pow(Math.pow(line.sx-x1,2)+Math.pow(line.sy-ystat,2),2.5) ;
                	    compy2 = ((2.*Math.pow(line.sy-ystat,2)-Math.pow(line.sx-x1,2))/4.*Math.PI)/Math.pow(Math.pow(line.sx-x1,2) + Math.pow(line.sy-ystat,2),2.5);

                            compx=-(compx1+(double)sig*compx2);
                            compy=-(compy1+(double)sig*compy2);

                	    line.emag = Math.sqrt(Math.pow(compx,2) + Math.pow(compy,2));

                	    line.ex = line.sx + delarc * (compx/line.emag);
                	    line.ey = line.sy + delarc * (compy/line.emag);


			    if(si != 0)
			        {
			    g.setColor(java.awt.Color.blue);
			    g.drawLine((int)line.sx, (int)line.sy, (int)line.ex, (int)line.ey);
			    g.drawLine(350-((int)line.sx-350),(int)line.sy,350-((int)line.ex-350),(int)line.ey);

//  draw lines from stationary magnet

			    g.drawLine((int)line.sx, -(int)line.sy+(int)ysum, (int)line.ex, -(int)line.ey+(int)ysum);
			    g.drawLine(350-((int)line.sx-350),-(int)line.sy+(int)ysum,350-((int)line.ex-350),-(int)line.ey+(int)ysum);
			    g.setColor(java.awt.Color.black);
			        }

                	    line.sx = line.ex;
                	    line.sy = line.ey;

                            ij++;
			    si++;
                	}
			    sii++;
			
			if(sii==15)
			{	
			g.setColor(java.awt.Color.white);
			g.fillRect(0,0,700,500);
			sii=0;
			}
			g.setColor(java.awt.Color.black);
                    iv++;
        	}

               if( sig > 0)
               {
// draw the three field lines from falling magnet going the other way

            iv=0;
    	    while(iv < 3)
         	{
                    if(sig<0)
                      {
	    	       line.ang = values[1][iv]*(Math.PI/180.);
                      }
                    else
                      {
	    	       line.ang = values[0][iv]*(Math.PI/180.);
                      }

        	    line.sx = x1 + 5 * Math.sin(line.ang);
        	    line.sy = y1 + 5 * Math.cos(line.ang);

                    distt=100.;
                    dists=100.;

        	    double delarc = 9.;
                    double intarc;
                    int ij;
                    double output1,output2;
                    intarc = delarc/3.;

                    ij = 0;
		    si = 0;

//   draw field lines from falling magnet, at three different angles

             	    while(ij < 100  && distt > 30.0 && dists > 30.0)
//             	    while(ij < 50  && distt > 30.0 )
                	{


                	    dist1 = Math.sqrt(Math.pow(line.sx-x1, 2) + Math.pow(line.sy - y1, 2));
                	    dists = Math.sqrt(Math.pow(line.sx-x1, 2) + Math.pow(line.sy - ystat, 2));
                          if (ij > 5)
                             {
                              distt=dist1;
                             }
                          else
                             {
                             distt=100.;
                             }
  
  
 			//compute components of dipole field of falling magnet

                	    compx1 = (3.*(line.sx-x1)*(line.sy-y1)/4.*Math.PI)/Math.pow(Math.pow(line.sx-x1,2)+Math.pow(line.sy-y1,2),2.5) ;
                	    compy1 = ((2.*Math.pow(line.sy-y1,2)-Math.pow(line.sx-x1,2))/4.*Math.PI)/Math.pow(Math.pow(line.sx-x1,2) + Math.pow(line.sy-y1,2),2.5);

 			//compute components of dipole field of stationary magnet

                	    compx2 = (3.*(line.sx-x1)*(line.sy-ystat)/4.*Math.PI)/Math.pow(Math.pow(line.sx-x1,2)+Math.pow(line.sy-ystat,2),2.5) ;
                	    compy2 = ((2.*Math.pow(line.sy-ystat,2)-Math.pow(line.sx-x1,2))/4.*Math.PI)/Math.pow(Math.pow(line.sx-x1,2) + Math.pow(line.sy-ystat,2),2.5);

                            compx=(compx1+(double)sig*compx2);
                            compy=(compy1+(double)sig*compy2);

                	    line.emag = Math.sqrt(Math.pow(compx,2) + Math.pow(compy,2));

                	    line.ex = line.sx + delarc * (compx/line.emag);
                	    line.ey = line.sy + delarc * (compy/line.emag);


			    if(si != 0)
			        {
			    g.setColor(java.awt.Color.blue);
			    g.drawLine((int)line.sx, (int)line.sy, (int)line.ex, (int)line.ey);
			    g.drawLine(350-((int)line.sx-350),(int)line.sy,350-((int)line.ex-350),(int)line.ey);

//  draw lines from stationary magnet

			    g.drawLine((int)line.sx, -(int)line.sy+(int)ysum, (int)line.ex, -(int)line.ey+(int)ysum);
			    g.drawLine(350-((int)line.sx-350),-(int)line.sy+(int)ysum,350-((int)line.ex-350),-(int)line.ey+(int)ysum);
			    g.setColor(java.awt.Color.black);
			        }

                	    line.sx = line.ex;
                	    line.sy = line.ey;

                            ij++;
			    si++;
                	}
			    sii++;
			
			if(sii==15)
			{	
			g.setColor(java.awt.Color.white);
			g.fillRect(0,0,500,500);
			sii=0;
			}
			g.setColor(java.awt.Color.black);
                    iv++;
        	}
   }


			g.setColor(java.awt.Color.white);
    			g.drawLine(rect.cx-rect.rw,(int)ystat-rect.rh+2,rect.cx-rect.rw,(int)ystat+rect.rh+2);
			g.drawOval(rect.cx-rect.rw,(int)ystat-rect.rh,(2*rect.rw),4);
    			g.drawLine(rect.cx+rect.rw,(int)ystat-rect.rh+2,rect.cx+rect.rw,(int)ystat+rect.rh+2);
			g.drawOval(rect.cx-rect.rw,(int)ystat+rect.rh,(2*rect.rw),4);

			g.setColor(java.awt.Color.black);

    			g.drawLine(rect.cx-rect.rw,(int)ystat-rect.rh+2,rect.cx-rect.rw,(int)ystat+rect.rh+2);
			g.drawOval(rect.cx-rect.rw,(int)ystat-rect.rh,(2*rect.rw),4);
    			g.drawLine(rect.cx+rect.rw,(int)ystat-rect.rh+2,rect.cx+rect.rw,(int)ystat+rect.rh+2);
			g.drawOval(rect.cx-rect.rw,(int)ystat+rect.rh,(2*rect.rw),4);

  	    brectcx = rect.cx;
	    brectcy = rect.cy;

	    nint.iterate();
	    xold[0]=nint.x[0]; xold[1]=nint.x[1];xold[2]=nint.x[2];

	    tim+=dtim;

	    xolder = xold[1] * 9;
		if(xolder > 45)
			{
			xolder = 45;
			}
		if(xolder < -45)
			{
			xolder = -45;
			}

//   g.drawLine(438,168,(438+(int)xolder),115);
//   g.drawLine(398,168,(398+(int)xolder),115);

//  do line plot at bottom
	    graph[0][ki] = 25.+(tim*40);
//          graph[1][ki] = 449. - Math.pow(xold[1],2);
            graph[1][ki] = 400. - 4.*xold[1];

	    g.setColor(Color.red);
	    g.setColor(Color.white);
//	    g.fillOval((int)graph[0][ki],(int)graph[1][ki],3,3);
	    ki++;

	    //System.out.println("ki = " +ki );
	    //System.out.println("Xcoord = " +(int)(25.+(tim*40)));
	    g.setColor(java.awt.Color.black);


//   g.drawOval(150,220,((2*(int)rada)-50),20);
//   g.drawOval(150,240,((2*(int)rada)-50),20);

//   g.drawLine(150,230,150,250);
 //         g.drawLine(300,230,300,250);

//   g.drawRect(25,350,450,100);

	    if (ki <= max)
		{

	    int bki = ki;
	    ki = 0;

	    while (ki < bki)
		{
			if(graph[1][ki] < 350) {g.setColor(java.awt.Color.white);}
			else if(graph[1][ki] > 350) {g.setColor(java.awt.Color.white);}
  	            g.fillOval((int)graph[0][ki],(int)graph[1][ki],3,3);
		    
		    ki++;
		}
	    ki = bki;
 	    }
		    
	    if(ki == max)
		{
		ki = 0;
		while (ki < max)
		    {
		    graph[0][ki] = graph[0][(ki+1)]-1;
		    graph[1][ki] = graph[1][(ki+1)];
		    ki++;
		    }
		ki = max -1;
    	 	}  	   
    	    }
    }

	g.setColor(java.awt.Color.black);


//draw ring
/*

	g.drawLine(125,230,125,250);
	g.drawLine(325,230,325,250);

	g.drawOval(125,220,(2*(int)rada),20);
	g.drawOval(125,240,(2*(int)rada),20);

	g.drawLine(150,230,150,250);
	g.drawLine(300,230,300,250);

	g.drawOval(150,220,((2*(int)rada)-50),20);
	g.drawOval(150,240,((2*(int)rada)-50),20);
*/
// draw moving magnet

    	g.drawLine(rect.cx-rect.rw,rect.cy-rect.rh+2,rect.cx-rect.rw,rect.cy+rect.rh+2);
	g.drawOval(rect.cx-rect.rw,rect.cy-rect.rh,(2*rect.rw),4);
    	g.drawLine(rect.cx+rect.rw,rect.cy-rect.rh+2,rect.cx+rect.rw,rect.cy+rect.rh+2);
	g.drawOval(rect.cx-rect.rw,rect.cy+rect.rh,(2*rect.rw),4);
// draw stationary magnet
    		g.drawLine(rect.cx-rect.rw,(int)ystat-rect.rh+2,rect.cx-rect.rw,(int)ystat+rect.rh+2);
		g.drawOval(rect.cx-rect.rw,(int)ystat-rect.rh,(2*rect.rw),4);
    		g.drawLine(rect.cx+rect.rw,(int)ystat-rect.rh+2,rect.cx+rect.rw,(int)ystat+rect.rh+2);
		g.drawOval(rect.cx-rect.rw,(int)ystat+rect.rh,(2*rect.rw),4);

//	g.drawRect(25,350,450,100);
    }

public boolean handleEvent(Event e)
    {
    Object target=e.target;

    if(target==timeScroll)
        {
        maxtim = timeScroll.getValue();
        timeLabel.setText("T =  " + maxtim);
        }
    if(target==qvalueScroll)
        {
        qvalue = qvalueScroll.getValue();
        qvalueLabel.setText("Friction = " + qvalue);
        }
    if(target==betaScroll)
        {
        betavalue = betaScroll.getValue();
        betaLabel.setText("Speed =  " + betavalue);
        }

    if (e.id==Event.ACTION_EVENT)
        {
       if(target==restartbutton)
            {
		x1 = 350.0;
		y1 = 30;
		go = 0;
		tim = 0;
		go = 0;
		repaint();
            }
        else if(target==signbutton)
            {
            sig = (-1*sig);
            repaint();
            }


        else if(target==gobutton)
            {
            	go = 1;
            	repaint();
            }
        }
    return super.handleEvent(e);
    }

}