// 3D non-perspective Convex,  Evgeny Demidov  8 Sep 2001
  import java.awt.*;
  import java.awt.event.*;
  import java.util.StringTokenizer;
  //import java.awt.image.*;
  public class applet-math-3d-convex extends java.applet.Applet
      implements MouseListener, MouseMotionListener {
    int nVert, nFace, h,w,h2,w2, mx0,my0, xPol[],yPol[];
    double fiX = .2, fiY = .3, dfi = .01, scale;
    int[][] face;
    double[][] vert, vert1, Norm;
    double[] Norm1z;
    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());
    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[nFace][];
    int tmp[] = new int[30];
    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();
    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];}
    for (int i = 0; i < nFace; i++)
     Norm1z[i] = m20*Norm[i][0] + m21*Norm[i][1] + m22*Norm[i][2];
  }
  
  public void mouseMoved(MouseEvent e) {}
  
  public void paint(Graphics g) {
    buffGraphics.clearRect(0, 0, w, h);
    for (int i = 0; i < nFace; i++){
     if (Norm1z[i] > 0){
      for (int j = 0; j < face[i].length; j++){
       xPol[j] = w2 + (int)vert1[face[i][j]][0];
       yPol[j] = h2 - (int)vert1[face[i][j]][1];}
      buffGraphics.setColor(col[(int)(Norm1z[i])]);
     buffGraphics.fillPolygon(xPol,yPol, face[i].length);}}
    g.drawImage(buffImage, 0, 0, this);
  //  showStatus( "fiX=" + (int)(360*fiX) + "   fiY=" + (int)(360*fiY));
  }
  public void update(Graphics g)   {  paint(g);  }
  
  }