/*
 * Globe.java (requires Java 1.2+)
 */

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.io.*;
import java.util.*;

class GlobeCanvas extends Component {
    BufferedImage image;
    int w, h;
    GlobeCanvas(BufferedImage _image) {
	image= _image;
	w = image.getWidth(null);
	h = image.getHeight(null);
	setSize(w, h);
    }
    public void paint(Graphics g) {
	//System.out.println("GlobeCanvas.paint()");
	g.drawImage(image, 0, 0, w, h, null);
    }
}

//-------------------------------------------------------------------------------------------

class GlobeImage extends BufferedImage {
    double rotbyd, rotbyr, cosine, sine;
    double rad;
    int w, h;
    Vector lines;

    class line {
	double p0[];
	double p1[];
	Color color;
	line(double _p0[], double _p1[], Color _color) {
	    p0= new double[3]; p0[0]= _p0[0];  p0[1]= _p0[1]; p0[2]= _p0[2];
	    p1= new double[3]; p1[0]= _p1[0];  p1[1]= _p1[1]; p1[2]= _p1[2];
	    color = _color;
	}
    }

    GlobeImage() {
	super(400, 400, BufferedImage.TYPE_3BYTE_BGR);
	w= 400;  h= 400;
	rad= 150;
	rotbyd= 15;
	rotbyr= rotbyd* 3.14159/180;
	cosine= Math.cos(rotbyr);  sine= Math.sin(rotbyr);
	createLines();
    }
    
    static double[] AltAzToXYZ(double alt, double az) {
	double altrad= (3.14159/180.0)* -alt;
	double azrad= (3.14159/180.0)* -az;
	double abscosaltrad= Math.abs(Math.cos(altrad));
	double x= Math.sin(azrad)*  abscosaltrad;
	double y= Math.sin(altrad);
	double z= Math.cos(azrad)*  abscosaltrad;
	//print '(%i, %i)-> (%i, %i, %i)' % (alt, az, x, y, z)
	double[] ret = new double[3];
	ret[0]= x;  ret[1]= y;  ret[2]= z;  
	return ret;
    }

    static void MultByRad(double[] xyz, double _rad) {
	xyz[0]*= _rad;
	xyz[1]*= _rad;
	xyz[2]*= _rad;
    }

    final void Rotate1(double[] pt) {
	double x= pt[0]; double y= pt[1];
	double x2= (x*cosine) + (y*sine);
	double y2= -(x*sine) + (y*cosine);
	pt[0]= x2;  pt[1]= y2;
    }

    final void Rotate2(double[] pt) {
	double x= pt[1]; double y= pt[2];
	double x2= (x*cosine) + (y*sine);
	double y2= -(x*sine) + (y*cosine);
	pt[1]= x2;  pt[2]= y2;
    }


    final void draw_line(double[] p0, double[] p1, Color color) {
	Graphics g= createGraphics();
	g.setColor(color);
	int w2= w/2;  int h2= h/2;
	g.drawLine((int)p0[0]+w2, (int)p0[1]+h2, (int)p1[0]+w2, (int)p1[1]+h2);
    }

    public void draw() {
	int w2= w/2;  int h2= h/2;
	Graphics g= createGraphics();
	g.setColor(Color.white);  g.fillRect(0, 0, w, h);
	for (int i=0; i<lines.size(); i++) {
	    line l = (line) lines.elementAt(i);
	    g.setColor(l.color);
	    double[] p0= l.p0;
	    double[] p1= l.p1;
	    g.drawLine((int)p0[0]+w2, (int)p0[1]+h2, (int)p1[0]+w2, (int)p1[1]+h2);
	}
    }


    void createLines() {
	System.gc();
	lines= new Vector();
        double alt= -80;
        while (alt< 70) {
            add_parallel(alt, Color.blue);
            alt= alt+ 10;
	}
	add_parallel(70, Color.red);
	add_parallel(80, Color.red);

	double az= 20;
        while (az < 360) {
            add_meridian(az, Color.blue);
            az= az+ 10;
	}

        add_meridian(0, Color.red);
        add_meridian(10, Color.green);
    }

    final void add_line(double[] p0, double[] p1, Color color) {
	line l= new line(p0, p1, color);
	lines.addElement(l);
    }


    final void add_parallel(double alt, Color color) {
        double az= 0;
        double[] p0= AltAzToXYZ(alt, az);
        MultByRad(p0, rad);
        while (az< 360) {
            az= az+ 10;
            double[] p1= AltAzToXYZ(alt, az);
            MultByRad(p1, rad);
            add_line(p0, p1, color);
	    p0 = p1;
	}
    }
        
    final void add_meridian(double az, Color color) {
        double alt= -90;
	double[] p0= AltAzToXYZ(alt, az);
        MultByRad(p0, rad);
        while (alt<= 90) {
            alt= alt+ 10;
            double[] p1= AltAzToXYZ(alt, az);
            MultByRad(p1, rad);
            add_line(p0, p1, color);
	    p0 = p1;
	}
    }

        
    void rotate1() {
	for (int i=0; i<lines.size(); i++) {
	    line l = (line) lines.elementAt(i);
            Rotate1(l.p0);
            Rotate1(l.p1);
	}
	draw();
    }            
        
    void rotate2() {
	for (int i=0; i<lines.size(); i++) {
	    line l = (line) lines.elementAt(i);
            Rotate2(l.p0);
            Rotate2(l.p1);
	}
	draw();
    }            

}


//-------------------------------------------------------------------------------------------

public class Globe extends Frame implements ActionListener, WindowListener {
    GlobeCanvas canvas;
    Panel buttons;
    Button bm, bm2;
    GlobeImage image;

    public void draw() {
	image.draw();
    }

    Globe() {
	super("Globe in Java");
	addWindowListener(this);
	setLayout(new BorderLayout());

	image= new GlobeImage();
	draw();
	canvas= new GlobeCanvas(image);  add("Center", canvas);  // "North" doesn't work

	buttons= new Panel();
	bm = new Button("Rotate1");  buttons.add(bm);  bm.addActionListener(this);
	bm2 = new Button("Rotate2");  buttons.add(bm2);  bm2.addActionListener(this);
	add("South", buttons);
	setSize(image.getWidth(), image.getHeight()+40);
	show();
    }

    
    public void actionPerformed(ActionEvent event)   {
	Object source = event.getSource();
	//System.out.println("ACTION_EVENT");
	if (source== bm) {
	    //System.out.println("Rotate1");
	    image.rotate1();
	    canvas.repaint();
	}
	else if (source== bm2) {
	    //System.out.println("Rotate2");
	    image.rotate2();
	    canvas.repaint();
	}
    }

    // What a pain...
    public void windowActivated(WindowEvent event) { }
    public void windowDeactivated(WindowEvent event) { }
    public void windowClosed(WindowEvent event) { }
    public void windowIconified(WindowEvent event) { }
    public void windowDeiconified(WindowEvent event) { }
    public void windowOpened(WindowEvent event) { }
    public void windowClosing(WindowEvent event) {
	System.exit(0);
    }

    public static void main(String[] args) {
	Globe inst = new Globe(); // create frame with title
    } // end main
}