// ortho.java   ortho projection

import java.awt.*;
import java.awt.event.*;

public class ortho extends Frame
{
  int winWidth = 500;
  int winHeight = 500;
  double cube[][] =  
    {{-1.0,-1.0,-1.0}, {1.0,-1.0,-1.0}, {1.0,1.0,-1.0}, {-1.0,1.0,-1.0}, 
     {-1.0,-1.0, 1.0}, {1.0,-1.0, 1.0}, {1.0,1.0, 1.0}, {-1.0,1.0, 1.0}};
  int colors[][] = 
    {{255,0,0},   {255,255,0}, {0,255,0},     {0,0,255}, 
     {255,0,255}, {0,255,255}, {128,128,128}, {0,0,0}};
  double M_PI = 3.14159265358979323846;
  double alpha = M_PI/6.0; // 30 deg
  double beta  = M_PI/4.0; // 45 deg
  boolean doedge = true;

  ortho()
  {
    System.out.println("ortho.java running");
    setTitle("ortho");
    setSize(winWidth,winHeight);
    setBackground(Color.white);
    setForeground(Color.black);
    addWindowListener(new WindowAdapter()
    {
      public void windowClosing(WindowEvent e)
      {
        System.exit(0);
      }
    });
    setVisible(true);
    this.addMouseListener (new mousePressHandler());
    System.out.println("ortho.java finished, see ortho.png");
  } // end ortho.java

  class mousePressHandler extends MouseAdapter
  {
    public void mousePressed (MouseEvent e)
    {
      int x, y, b;
      x = e.getX();
      y = e.getY();
      b = e.getButton();

      if(b==3) doedge = !doedge;
      if(b==1) // quadrant select
      {
	if(x<winWidth/2 && y<winHeight/2) alpha = alpha + M_PI/36.0;
	if(x<winWidth/2 && y>winHeight/2) alpha = alpha - M_PI/36.0;
	if(x>winWidth/2 && y<winHeight/2) beta = beta + M_PI/36.0;
	if(x>winWidth/2 && y>winHeight/2) beta = beta - M_PI/36.0;
      }
      requestFocus();
      repaint();
    }
  }

  public void paint(Graphics g)
  {
    if(doedge) edgecube(g);
    else       colorcube(g);
    g.drawString("ortho.java  x,y,z", 20, winHeight-20);
    g.drawString("alpha="+Double.toString(alpha*180.0/M_PI), 20, 40);
    g.drawString("beta ="+Double.toString(beta*180.0/M_PI), 20, 60);
    g.drawString("angle alpha", winWidth/2-90, winHeight-30);
    g.drawString("angle beta" , winWidth/2+40, winHeight-30);

  }

  void polygon(int a, int b, int c , int d, int col, Graphics g)
  {
    int xp[] = {0, 1, 2, 3};
    int yp[] = {0, 1, 2, 3};
    int np = 4;
    int xc = winWidth/2;
    int yc = winHeight/2+10;
    double px1 = cube[a][0];
    double py1 = cube[a][1];
    double pz1 = cube[a][2];
    double px2 = cube[b][0];
    double py2 = cube[b][1];
    double pz2 = cube[b][2];
    double px3 = cube[c][0];
    double py3 = cube[c][1];
    double pz3 = cube[c][2];
    double px4 = cube[d][0];
    double py4 = cube[d][1];
    double pz4 = cube[d][2];
    double scale = (double)(winWidth/4-25);

    xp[0] = xc + (int)(scale*(px1*Math.cos(alpha) + py1*Math.cos(beta)));
    yp[0] = yc - (int)(scale*(py1*Math.sin(beta) - px1*Math.sin(alpha) + pz1));
    xp[1] = xc + (int)(scale*(px2*Math.cos(alpha) + py2*Math.cos(beta)));
    yp[1] = yc - (int)(scale*(py2*Math.sin(beta) - px2*Math.sin(alpha) + pz2));
    xp[2] = xc + (int)(scale*(px3*Math.cos(alpha) + py3*Math.cos(beta)));
    yp[2] = yc - (int)(scale*(py3*Math.sin(beta) - px3*Math.sin(alpha) + pz3));
    xp[3] = xc + (int)(scale*(px4*Math.cos(alpha) + py4*Math.cos(beta)));
    yp[3] = yc - (int)(scale*(py4*Math.sin(beta) - px4*Math.sin(alpha) + pz4));
    g.setColor(new Color(colors[col][0], colors[col][1], colors[col][2]));
    g.fillPolygon(xp, yp, np);
  } // end polygon

  void colorcube(Graphics g)
  {
    // map vertices with color to faces 
    polygon(1, 0, 3, 2, 0, g);
    polygon(3, 7, 6, 2, 1, g);
    polygon(7, 3, 0, 4, 2, g);
    polygon(2, 6, 5, 1, 3, g);
    polygon(4, 5, 6, 7, 4, g);
    polygon(5, 4, 0, 1, 5, g);
  } // end colorcube

  void edge(int a, int b, int col, Graphics g)
  {
    int x1, y1, x2, y2; // screen x,y coordinates
    int xc = winWidth/2;
    int yc = winHeight/2+10;
    double px1 = cube[a][0];
    double py1 = cube[a][1];
    double pz1 = cube[a][2];
    double px2 = cube[b][0];
    double py2 = cube[b][1];
    double pz2 = cube[b][2];
    double scale = (double)(winWidth/4-25);

    x1 = xc + (int)(scale*(px1*Math.cos(alpha) + py1*Math.cos(beta)));
    y1 = yc - (int)(scale*(py1*Math.sin(beta) - px1*Math.sin(alpha) + pz1));
    x2 = xc + (int)(scale*(px2*Math.cos(alpha) + py2*Math.cos(beta)));
    y2 = yc - (int)(scale*(py2*Math.sin(beta) - px2*Math.sin(alpha) + pz2));
    g.setColor(new Color(colors[col][0], colors[col][1], colors[col][2]));
    g.drawLine(x1, y1, x2, y2);
    if(px1<0.0 && py1<0.0 && pz1<0.0) g.drawString("-1,-1,-1", x1, y1);
    if(px1>0.0 && py1>0.0 && pz1<0.0) g.drawString("1,1,-1", x1, y1);
    if(px1>0.0 && py1<0.0 && pz1<0.0) g.drawString("1,-1,-1", x1, y1);
    if(px1<0.0 && py1>0.0 && pz1<0.0) g.drawString("-1,1,-1", x1, y1);
    if(px1>0.0 && py1>0.0 && pz1>0.0) g.drawString("1,1,1", x1, y1);
    if(px1>0.0 && py1<0.0 && pz1>0.0) g.drawString("1,-1,1", x1, y1);
    if(px1<0.0 && py1>0.0 && pz1>0.0) g.drawString("-1,1,1", x1, y1);
    if(px1<0.0 && py1<0.0 && pz1>0.0) g.drawString("-1,-1,1", x1, y1);
  } // end polygon

  void edgecube(Graphics g)
  {
    // map vertices with color to faces 
    edge(0, 1, 0, g);
    edge(1, 2, 1, g);
    edge(2, 3, 2, g);
    edge(3, 0, 3, g);
    edge(4, 5, 0, g);
    edge(5, 6, 1, g);
    edge(6, 7, 2, g);
    edge(7, 4, 3, g);
    edge(0, 4, 4, g);
    edge(1, 5, 5, g);
    edge(2, 6, 6, g);
    edge(3, 7, 7, g);
  } // end edgecube

  public static void main(String args[])
  {
    new ortho();
  }
} // end ortho.java