//<pre>
import java.util.*;

public class vpuff extends VolumeApplet
{
   Random R = new Random(0);
   int blur = 20, mode = 0;
   double P[][];
   double freq = 6.;

   boolean isAddingNoise = false;
   public void setAddingNoise(boolean tf) {
      isAddingNoise = tf;
      freshStart();
   }

   // THINGS TO INITIALIZE WHEN STARTING THE APPLET

   public void initialize() {

      setSpecular(.5,.7,.7,.01);
      setAmbient(.5,0,0);

      // CREATE CLOUD OF PARTICLES

      P = new double[200][3];
      for (int i = 0 ; i < P.length ; i++) {
         double rr = 10;
         do {
	    double z = (1 - 2. * i / P.length);
	    P[i][2] = z;
	    double r = Math.sqrt(1 - z*z);
            P[i][0] = r * (2 * (R.nextDouble() % 1) - 1);
            P[i][1] = r * (2 * (R.nextDouble() % 1) - 1) / 1.414;
	    rr = P[i][0]*P[i][0] + 2*P[i][1]*P[i][1] + P[i][2]*P[i][2];
         } while (rr > 1.01);
      }

      C = 1;
      S = 0;
   }

   double r = .3, rxr = r*r;
   int i0 = 0;

   public void restart() {
      i0 = 0;
   }

   public double density(double x, double y, double z) {

      x /= .7;
      y /= .7;
      z /= .7;

      for ( ; i0 < P.length ; i0++)
         if (P[i0][2] < z+r)
            break;

      double d = 0;
      for (int i = i0 ; i < P.length && P[i][2] > z-r ; i++) {
         double pu = P[i][0], py = P[i][1], pv = P[i][2];
	 double px = C * pu - S * pv;
	 double pz = S * pu + C * pv;
	 px -= x; py -= y; pz -= z;
         double rr = (px*px + py*py + pz*pz) / rxr;
	 if (rr < 1)
	    d += .5 + .5 * Math.cos(Math.PI * Math.sqrt(rr));
      }
      if (d > 0) {
	 if (isAddingNoise)
            d += 4 * addNoise(x, y, z);
         d = Math.max(.01, Math.min(.99, d));
         d = .1 * filter(d);
      }
      return d;
   }

   double rot = Math.PI/3, c = Math.cos(rot), s = Math.sin(rot);
   double addNoise(double x, double y, double z) {
      double u, v;
      x += 100;
      double d = 0;
      d += abn(1, x,y,z); u = x; v = y; x = c*u-s*v; y = s*u+c*v;
      d += abn(2, x,y,z); u = x; v = y; x = c*u-s*v; y = s*u+c*v;
      d += abn(4, x,y,z);
      return 1.2 * d / freq;
   }
   double abn(double f, double x, double y, double z) {
      double freq = this.freq * f;
      return (Math.abs(ImprovedNoise.noise(freq*x,freq*y,freq*z))-.5)/f;
   }

   double filter(double t) {
      t = bias(t, .67);
      if (t < .5)
         t = gain(t, .86);
      t = bias(t, .35);
      return t;
   }
}