// 3D non-perspective fractal Sponges,  Evgeny Demidov  10 Oct 2001
  import java.awt.*;
  import java.awt.event.*;
  import java.util.StringTokenizer;
  //import java.awt.image.*;
  public class applet-math-3d-sponge extends java.applet.Applet
      implements MouseListener, MouseMotionListener {
    int nVert, nFace, it, h,w,h2,w2, mx0,my0, xPol[],yPol[], Zsort[];
    double fiX = .2, fiY = .3, dfi = .01, scale, scl;
    int[][] face;
    double[][] vert, vert1, Norm;
    double[] Norm1z;
    Image buffImage;     Graphics buffGraphics;
    Color[] col;
    boolean painted;
  
  public void init() {
    w = getSize().width;   h = getSize().height;
    w2 = w/2;  h2 = h/2;
    String s=getParameter("par");
    StringTokenizer st = new StringTokenizer(s);
    it = Integer.parseInt(st.nextToken());
    scl = Double.valueOf(st.nextToken()).doubleValue();
    s=getParameter("N");  st = new StringTokenizer(s);
    nVert = Integer.parseInt(st.nextToken());
    nFace = Integer.parseInt(st.nextToken());
    vert = new double[nVert][3];  vert1 = new double[nVert][3];
    s=getParameter("Vert");
    st = new StringTokenizer(s, " ,");
    double max = 0;
    for (int i = 0; i < nVert; i++){
     vert[i][0] = Double.valueOf(st.nextToken()).doubleValue();
     vert[i][1] = Double.valueOf(st.nextToken()).doubleValue();
     vert[i][2] = Double.valueOf(st.nextToken()).doubleValue();
     double vv = vert[i][0]*vert[i][0] + vert[i][1]* vert[i][1] +
      vert[i][2]* vert[i][2];
     if ( max < vv) max = vv;}
    scale = w2 / Math.sqrt(max);
    face = new int[nFace][];
    int tmp[] = new int[30];
    Zsort = new int[nVert];
    for (int i = 0; i < nVert; i++) Zsort[i] = i;
    s=getParameter("Faces");
    st = new StringTokenizer(s);
    for (int i = 0; i < nFace; i++){
     int l = 0;
     while ( (tmp[l]=Integer.parseInt(st.nextToken())) != -1) l++;
     face[i] = new int[l];
     for (int j = 0; j < l; j++) face[i][j] = tmp[j];}
    buffImage = createImage(w, h);   buffGraphics = buffImage.getGraphics();
    col = new Color[256];
    Norm = new double[nFace][3];  Norm1z = new double[nFace];
    for (int i = 0; i < nFace; i++){
     Norm[i][0] = (vert[face[i][1]][1] - vert[face[i][0]][1])*
      (vert[face[i][2]][2] - vert[face[i][1]][2]) -
      (vert[face[i][2]][1] - vert[face[i][1]][1])*
      (vert[face[i][1]][2] - vert[face[i][0]][2]);
     Norm[i][1] = -(vert[face[i][1]][0] - vert[face[i][0]][0])*
      (vert[face[i][2]][2] - vert[face[i][1]][2]) +
      (vert[face[i][2]][0] - vert[face[i][1]][0])*
      (vert[face[i][1]][2] - vert[face[i][0]][2]);
     Norm[i][2] = (vert[face[i][1]][0] - vert[face[i][0]][0])*
      (vert[face[i][2]][1] - vert[face[i][1]][1]) -
      (vert[face[i][2]][0] - vert[face[i][1]][0])*
      (vert[face[i][1]][1] - vert[face[i][0]][1]);
     double mod = Math.sqrt(Norm[i][0]*Norm[i][0] + Norm[i][1]*Norm[i][1] +
      Norm[i][2]*Norm[i][2]) / 255.5;
     Norm[i][0] /= mod;    Norm[i][1] /= mod;    Norm[i][2] /= mod;}
    xPol = new int[30];  yPol = new int[30];
    for (int i = 0; i < 256; i++) col[i] = new Color(i, i, i);
    s = getParameter("bgColor"); if (s != null){
     st = new StringTokenizer(s);
     int red = Integer.parseInt(st.nextToken());
     int green = Integer.parseInt(st.nextToken());
     int blue = Integer.parseInt(st.nextToken());
     setBackground( new Color(red, green, blue));}
    else setBackground(new Color(255,255,255));
    addMouseListener(this);
    addMouseMotionListener(this);
    rotate();
  }
  public void destroy() {
    removeMouseListener(this);
    removeMouseMotionListener(this);
  }
  public void mouseClicked(MouseEvent e){}       // event handling
  public void mousePressed(MouseEvent e) {
    mx0 = e.getX();  my0 = e.getY();
    if ( e.isControlDown() ) {
      it--;  if (it < 0) it = 0;
      painted = false;
      repaint();}
    if ( e.isAltDown() ){
      it++;
      painted = false;
      repaint();}
    e.consume();
  }
  public void mouseReleased(MouseEvent e){}
  public void mouseEntered(MouseEvent e) {}
  public void mouseExited(MouseEvent e)  {}
  public void mouseDragged(MouseEvent e) {
    int x1 = e.getX();  int y1 = e.getY();
    fiY += dfi*(x1 - mx0);   mx0 = x1;
    fiX += dfi*(y1 - my0);   my0 = y1;
    rotate();
    repaint();
    e.consume();
  }
  
  public void rotate(){
    double ct = Math.cos(fiX), cf = Math.cos(fiY),
           st = Math.sin(fiX), sf = Math.sin(fiY),
           m00 =  scale*cf,    m02 =  scale*sf,
           m10 = scale*st*sf, m11 =  scale*ct, m12 = -scale*st*cf,
           m20 = -ct*sf, m21 = st, m22 = ct*cf;
    for (int i = 0; i < nVert; i++){
     vert1[i][0] = m00*vert[i][0] + m02*vert[i][2];
     vert1[i][1] = m10*vert[i][0] + m11*vert[i][1] + m12*vert[i][2];
     vert1[i][2] = m20*vert[i][0] + m21*vert[i][1] + m22*vert[i][2];}
    for (int i = 0; i < nFace; i++)
     Norm1z[i] = m20*Norm[i][0] + m21*Norm[i][1] + m22*Norm[i][2];
  
    for (int i = nVert - 1; --i >= 0;) {
      boolean flipped = false;
      for (int j = 0; j <= i; j++) {
        int a = Zsort[j],  b = Zsort[j + 1];
        if (vert1[a][2] > vert1[b][2]) {
          Zsort[j + 1] = a;   Zsort[j] = b;
          flipped = true;
        }
      }
      if (!flipped) break;
    }
    painted = false;
  }
  
  public void mouseMoved(MouseEvent e) {}
  
  public void paint(Graphics g) {
    if ( !painted ){
     buffGraphics.clearRect(0, 0, w, h);
     recursion(it, 0, 0, 1, 1-1/scl);
     painted = true;}
    g.drawImage(buffImage, 0, 0, this);
  }
  
  public void recursion(int n, double Xo, double Yo, double sc, double tr) {
    if (n == 0) drawPolygon(Xo, Yo, sc);
    else{
     for (int i = 0; i < nVert; i++){
      int is = Zsort[i];
      recursion(n-1, Xo + vert1[is][0]*tr, Yo + vert1[is][1]*tr, sc/scl, tr/scl);}}
  }                         
  
  public void drawPolygon(double Xo, double Yo, double sc) {
    for (int i = 0; i < nFace; i++){
     if (Norm1z[i] > 0){
      for (int j = 0; j < face[i].length; j++){
       xPol[j] = w2 + (int)(Xo + vert1[face[i][j]][0]*sc);
       yPol[j] = h2 - (int)(Yo + vert1[face[i][j]][1]*sc);}
      buffGraphics.setColor(col[(int)(Norm1z[i])]);
     buffGraphics.fillPolygon(xPol,yPol, face[i].length);}}
  }
  public void update(Graphics g)   {  paint(g);  }
  
  }