// 3D non-perspective Stellated polyhedra,  Evgeny Demidov  9 Sep 2001
  import java.awt.*;
  import java.awt.event.*;
  import java.util.StringTokenizer;
  public class applet-math-3d-stella extends java.applet.Applet
      implements MouseListener, MouseMotionListener {
    int nVert, nFace, nRay, h,w,h2,w2, mx0,my0;
    int face[][][], xPol[],yPol[], Zsort[];
    double fiX = .2, fiY = .3, dfi = .01, scale;
    double vert[][],vert1[][], Norm[][][],Norm1z[][], ray[][], ray1z[];
    Image buffImage;     Graphics buffGraphics;
    Color[] col;
  
  public void init() {
    w = getSize().width;   h = getSize().height;
    w2 = w/2;  h2 = h/2;
    String s=getParameter("N");  StringTokenizer st = new StringTokenizer(s);
    nVert = Integer.parseInt(st.nextToken());
    nRay = Integer.parseInt(st.nextToken());
    nFace = Integer.parseInt(st.nextToken());
    vert = new double[nVert][3];  vert1 = new double[nVert][2];
    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[nRay][nFace][];
    ray = new double[nRay][3];  ray1z = new double[nRay];
    Zsort = new int[nRay];
    int tmp[] = new int[30];
    for (int r = 0; r < nRay; r++){
     Zsort[r] = r;
     s=getParameter("Faces" + r);  st = new StringTokenizer(s);
     int m = 0;
     for (int i = 0; i < nFace; i++){
      int l = 0;
      while ( (tmp[l]=Integer.parseInt(st.nextToken())) != -1) l++;
  //System.out.println(" r="+r+"  i="+i);
      face[r][i] = new int[l];
      for (int j = 0; j < l; j++){
       face[r][i][j] = tmp[j];
       ray[r][0] += vert[tmp[j]][0]; 
       ray[r][1] += vert[tmp[j]][1];
       ray[r][2] += vert[tmp[j]][2];  m++;}}
     ray[r][0] /= m;   ray[r][1] /= m;   ray[r][2] /= m;}
    buffImage = createImage(w, h);   buffGraphics = buffImage.getGraphics();
    col = new Color[256];
    Norm = new double[nRay][nFace][3];  Norm1z = new double[nRay][nFace];
    for (int r = 0; r < nRay; r++){
     for (int i = 0; i < nFace; i++){
      Norm[r][i][0] = (vert[face[r][i][1]][1] - vert[face[r][i][0]][1])*
       (vert[face[r][i][2]][2] - vert[face[r][i][1]][2]) -
       (vert[face[r][i][2]][1] - vert[face[r][i][1]][1])*
       (vert[face[r][i][1]][2] - vert[face[r][i][0]][2]);
      Norm[r][i][1] = -(vert[face[r][i][1]][0] - vert[face[r][i][0]][0])*
       (vert[face[r][i][2]][2] - vert[face[r][i][1]][2]) +
       (vert[face[r][i][2]][0] - vert[face[r][i][1]][0])*
       (vert[face[r][i][1]][2] - vert[face[r][i][0]][2]);
      Norm[r][i][2] = (vert[face[r][i][1]][0] - vert[face[r][i][0]][0])*
       (vert[face[r][i][2]][1] - vert[face[r][i][1]][1]) -
       (vert[face[r][i][2]][0] - vert[face[r][i][1]][0])*
       (vert[face[r][i][1]][1] - vert[face[r][i][0]][1]);
      double mod = Math.sqrt(Norm[r][i][0]*Norm[r][i][0] +
       Norm[r][i][1]*Norm[r][i][1] + Norm[r][i][2]*Norm[r][i][2]) / 255.5;
      Norm[r][i][0] /= mod;    Norm[r][i][1] /= mod;    Norm[r][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);
    setBackground(new Color(200,200,255));
    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();
    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 mouseMoved(MouseEvent e){}
  
  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];}
    for (int r = 0; r < nRay; r++){
     ray1z[r] = m20*ray[r][0] + m21*ray[r][1] + m22*ray[r][2];
     for (int i = 0; i < nFace; i++)
      Norm1z[r][i] = m20*Norm[r][i][0] + m21*Norm[r][i][1] + m22*Norm[r][i][2];}
  
    for (int i = nRay - 1; --i >= 0;) {
      boolean flipped = false;
      for (int j = 0; j <= i; j++) {
        int a = Zsort[j],  b = Zsort[j + 1];
        if (ray1z[a] > ray1z[b]) {
          Zsort[j + 1] = a;   Zsort[j] = b;
          flipped = true;
        }
      }
      if (!flipped) break;
    }
  }
  
  public void paint(Graphics g) {
    buffGraphics.clearRect(0, 0, w, h);
    for (int r = 0; r < nRay; r++){
     int rs = Zsort[r];
     for (int i = 0; i < nFace; i++){
      if (Norm1z[rs][i] > 0){
       for (int j = 0; j < face[rs][i].length; j++){
        xPol[j] = w2 + (int)vert1[face[rs][i][j]][0];
        yPol[j] = h2 - (int)vert1[face[rs][i][j]][1];}
       buffGraphics.setColor(col[(int)(Norm1z[rs][i])]);
      buffGraphics.fillPolygon(xPol,yPol, face[rs][i].length);}}}
    g.drawImage(buffImage, 0, 0, this);
  //  showStatus( "fiX=" + (int)(360*fiX) + "   fiY=" + (int)(360*fiY));
  }
  public void update(Graphics g)   {  paint(g);  }
  
  }