//spiral3.java
//  a real memory hog,  spins a 3 ring spiral
//ababian
//to do:
//compressed frames (?)-probably won't do

import java.awt.*;
import java.awt.image.*;
import java.applet.*;

public class spiral3 extends Applet implements Runnable {//display spiral figure
/*display diagram of 3 rings (one circle, two rings) of spirals alternating direction
formula for spiral in polar coords,:  th=a*r+b */
//command-line parameters:
  //spiralconstant=20,  how windy the spiral gets
  int numarms=5; //number of spiral arms
  int numframes=5; // number of frames to store
  int frametime=100; // how long per frame,  interacts with numframes to give rotation speed
  double delr=.2; // (increment for radius in plotting) smaller is slower startup /better graphics
  double ringoffset=0; //angle offset between rings
  Color color1=new Color(255,255,255);  //background color (white) input from command line as hex,  
  Color color2=new Color(0,0,0); //spiral color,  black default

  //other variables
  static double pi2=java.lang.Math.PI*2;
  double delth; //( angle width of arm )
  int rmax; // maximum radius
  double a; //spiral multiplier global
  Dimension size;
  int cur=0;  //current frame buffer
  Image frames[];
  Thread cotton;
  boolean frozen=false;
  
public void init() {
    int ac;
    String s;
    size=size();    

    if ((s = getParameter("numframes")) != null) 
       numframes= Integer.parseInt(s); //else numframes=10; 

    if ((s = getParameter("numarms")) != null) 
       numarms= Integer.parseInt(s); //else numarms=5; 

    if ((s = getParameter("spiralconstant")) != null)
       ac= Integer.parseInt(s); 
    else ac=20; 

    if ((s = getParameter("frametime")) != null)
       frametime= Integer.parseInt(s); //else frametime=10;

   if ((s = getParameter("color1")) != null) 
          try { color1= new Color(Integer.parseInt(s,16)); }
          catch (Exception e) {
            System.out.println("error with param color1 "+e);
            color1=new Color(255,255,255);} //background color,  white default
      //else color1=new Color(255,255,255);

   if ((s = getParameter("color2")) != null) 
          try { color2= new Color(Integer.parseInt(s,16)); }
          catch (Exception e) {
            System.out.println("error with param color2 "+e);
            color1=new Color(0,0,0);} //foreground color,  black default
      //else color2=new Color(0,0,0);
  
   if ((s = getParameter("delr")) != null) 
         try {delr= (new Double(s)).doubleValue();}
         catch (Exception e) {
           System.out.println("error with param delr "+e);
	   delr=1.0;}

    setBackground(color1);
    setForeground(color2);
    rmax=java.lang.Math.min(size.width,size.height)/2-1; // maximum radius
    a=(ac/10)*pi2/rmax; //spiral multiplier global  (r=rmax,  th=2*pi,  th=a*r,  a=th/r=6pi/rmax
    delth=pi2/numarms; //( angle width of 2 arms (black and white)), =pi/numarms 
    ringoffset=2*a*(rmax/3); 
    frames=new Image[numframes];
    cur=0;
    for (int i=0;i<numframes;i++){
        frames[i]=createImage(size.width,size.height);
        oneimage(i);} }

    public void paint(Graphics g){ update( g); }

    public void update(Graphics g) {
	g.drawImage(frames[cur],0,0,this);}

    public void start() {      
        cur=0;
        if (frozen) {} // do nothing 
        else {
	   if (cotton==null) {cotton=new Thread(this);}
           cotton.start(); }}

    public void stop() {
        cotton=null;}

    public void run() {
        cur=0;
        while (Thread.currentThread() == cotton) {
        try {Thread.currentThread().sleep(frametime);} 
        catch (InterruptedException e){};
        cur=(cur+1)%numframes;
        repaint(); } }

public void oneimage(int count){
    Graphics g=frames[count].getGraphics();
    g.setColor(color1);
    g.fillRect(0,0,size.width,size.height);
    g.setColor(color2);
     draw1frame(count*delth/numframes,g); }//instead of count*2pi/numframes
    
    public boolean mouseEnter(Event eve, int x, int y) {
	try {getAppletContext().showStatus("Stare at this for 20 seconds and then look at something else");}
	  catch  (Exception e) {System.out.println("Status error");}
	return true; }


public boolean mouseDown(Event e,int x,int y) {
	if (frozen){
           frozen=false;
 	   start();}
	else {
	   frozen=true;
	   stop(); }
    return true;}

  
public void draw1frame(double boffset, Graphics g){
  int r3rd,r2_3rd;
  double delth2,bfinal,b;
   r3rd=rmax/3;
   r2_3rd=2*r3rd;
   bfinal=pi2+boffset;
   g.drawArc(1,1,2*rmax,2*rmax,0,360);
   g.drawArc(rmax-r3rd+1,rmax-r3rd+1,2*r3rd,2*r3rd,0,360);
   g.drawArc(rmax-r2_3rd+1,rmax-r2_3rd+1,2*r2_3rd,2*r2_3rd,0,360);

for (b=boffset;b<bfinal;b+=delth){// formula for start angle th=a*r+b, r=2/3*rmax
    drawarm(0,r3rd,b,a,g);
    drawarm(r3rd,r2_3rd,b+ringoffset-delth/2,-a,g);
    drawarm(r2_3rd,rmax,b-ringoffset,a,g);}}

public void drawarm(double r1, double r2, double b, double a, Graphics g){
//always draws around arm counterclockwise
   Polygon paul=new Polygon();
   int numedgepoints=7,i;
   double delthedge=delth/(numedgepoints+1);
   double r,th,newb=b+delth/2;
   th=a*r1+newb;
   for (i=1;i<=numedgepoints;i++)  //inner curve edge
      paul.addPoint(xfrompolar(r1,th-i*delthedge),yfrompolar(r1,th-i*delthedge));

   for (r=r1;r<r2;r+=delr) { //up one side of spiral
      th=a*r+b;
      paul.addPoint(xfrompolar(r,th),yfrompolar(r,th));}

    th=a*r2+b;
   for (i=1;i<=numedgepoints;i++) //outer curve edge
      paul.addPoint(xfrompolar(r2,th+i*delthedge),yfrompolar(r2,th+i*delthedge));

      
   for (;r>r1;r-=delr) { //down other side of spiral arm
      th=a*r+newb;
      paul.addPoint(xfrompolar(r,th),yfrompolar(r,th));}
   g.fillPolygon(paul);}
   
public int xfrompolar(double r,double th){ // xcoord from polar
   return (int) java.lang.Math.round(r*java.lang.Math.cos(th))+rmax+1;}

public int yfrompolar(double r,double th){ // xcoord from polar
   return (int) java.lang.Math.round(r*java.lang.Math.sin(th))+rmax+1;}

}