// Particle.java

import java.awt.Color;
import java.awt.Graphics;

class Particle {
   Particle()
   {  xpts = new int[3];   ypts = new int[3];   gray = new int[3];
      npts = 0;   phase = 0;   counter = -1;   skipSegment = -1;
      resetFlag = false;   exists = false;
   }

   void set(float f, float f1, Singularity singularity)
   {  s = singularity;
      dx = f;   dy = f1;
      x = s.x + dx;   y = s.y + dy;
      npts = 0;   phase = 0;
      counter = -1;   skipSegment = -1;
      resetFlag = false;   exists = true;
   }

   public synchronized void addPoint(int i, int j, int k)
   {  xpts[phase] = i;   ypts[phase] = j;   gray[phase] = k;
      if(resetFlag) {skipSegment = phase;  counter = 3;  resetFlag = false;}
      phase = (phase + 1) % 3;
      npts = Math.min(3, npts + 1);
   }

   public synchronized void drawSimple(Graphics g)
   {  g.setColor(Color.white);
     int i = xpts[0];
     int j = ypts[0];
      g.drawLine(i, j, i, j);
   }

   public synchronized void draw(Graphics g)
   { int i2 = 2;
     boolean flag = false;
      if(npts < 3) {
         i2 = npts - 1;
        int l2 = 42 / npts;
        int i = xpts[0];
        int k = ypts[0];
         for(int l3 = 0; l3 < i2; l3++) {
           int j2 = l3 + 1;
           int j3 = gray[j2] + j2 * l2;
            g.setColor(new Color(j3, j3, j3));
           int i1;
           int k1;
            g.drawLine(i, k, i1 = xpts[j2], k1 = ypts[j2]);
            i = i1;
            k = k1;
         }
         if(skipSegment > -1) counter--;
         if(counter == 0)     skipSegment = -1;
      }
      else {
        int j = xpts[phase];
        int l = ypts[phase];
        int i3 = 42 / i2;
         for(int i4 = 0; i4 < i2; i4++) {
           int k2 = (i4 + 1 + phase) % 3;
           int k3 = gray[k2] + (i4 + 1) * i3;
            g.setColor(new Color(k3, k3, k3));
           int j1 = xpts[k2];
           int l1 = ypts[k2];
            if(k2 != skipSegment && Math.abs(j1 - j) < 10 &&
                                    Math.abs(l1 - l) < 10)
               g.drawLine(j, l, j1, l1);
            j = j1;
            l = l1;
         }
         if(skipSegment > -1)  counter--;
         if(counter == 0)      skipSegment = -1;
      }
   }

   public void reset()  {x = s.x + dx;  y = s.y + dy;  resetFlag = true;}

   private static final int MAXPTS         = 3;
   private static final int MAXLINES       = 2;
   private static final int COLOR_HEADROOM = 42;
   private boolean resetFlag;
   private int     skipSegment;
   private int     counter;
   private int     xpts[];
   private int     ypts[];
   private int     gray[];
   private int     npts;
   private int     phase;
   public boolean  exists;
   Singularity s;
   float x, y;
   float dx, dy;
}