//	Theresa L. Walunas
//	SE 450, Tuesday Night Class
//	Homework #3: Animation Applet
//	Due: 4/18/00

import java.awt.*;

public class FallingStar
	extends java.applet.Applet implements Runnable {

     	protected Image image;
     	protected Graphics offscreen;
     	protected Dimension d;
	
	//	Background color fields (taken from HTML)
	protected int bkgdr, bkgdg, bkgdb;
	
	//	Printed text fields
	Font titlefont, caughtfont;
	String title,caught;

	//	3D Rectangle Fields
	protected int xrect, yrect;
	protected int dxrect = -2, dyrect= 5;
	protected int rgfh = 2, rgfw = 2;
	protected int rech, recw;

	//	Polygon Fields
	protected int polypoints=5;
	protected int dx = 0, dy = 5, rnd, shift;
	protected int polyx[]= {12, 36, 6, 30, 18};
	protected int polyy[]= {30, 12, 12, 30, 0};
	protected Polygon p = new java.awt.Polygon (polyx, polyy, polypoints);
	protected Rectangle rp = new java.awt.Rectangle();
	protected Rectangle r = new java.awt.Rectangle();


     	public void init() {
		//  Parameterized background color set up
		String color = getParameter("bkgdr");
		if (color != null){
			bkgdr = Integer.parseInt(color);
		}
		else {
			bkgdr = 0;
		}

		color = getParameter("bkgdg");
		if (color != null){
			bkgdg = Integer.parseInt(color);
		}
		else {
			bkgdg = 0;
		}

		color = getParameter("bkgdb");
		if (color != null){
			bkgdb = Integer.parseInt(color);
		}
		else {
			bkgdb = 0;
		}

		//  Parameterized frames per second
		String frames = getParameter("fps");
		if (frames != null){
			delay = 1000/Integer.parseInt(frames);
		}
		else {
			delay = 100;
		}

		//  Initialize Text Settings
		titlefont = new Font("Helvetica", Font.BOLD, 24);
		caughtfont = new Font("Helvetica", Font.PLAIN, 12);
		title = "Catch a Falling Star";
		caught = "Caught the Falling Star!";
		
		//  Determine size of applet space
		d = getSize();

		//  Create randomized dimensions for 3D rectangle
		xrect = d.width/2;
		yrect = d.height/2;
		
		rech = (int)(Math.random() * d.height * 0.25);
		recw = (int)(Math.random() * d.width * 0.25);
		r = new Rectangle(xrect,yrect,recw, rech);	
     	}	


	public void update (Graphics g) {

		//  Create randomized colors for shapes

		int red = (int)(Math.random() *256);
		int blue = (int)(Math.random() *256);
		int green = (int)(Math.random() *256);

          	//  Create off-screen image buffer if it is
	  	//  invoked for the first time.
   	  	if (image == null) {
	       		image = createImage (d.width, d.height);
	       		offscreen = image.getGraphics();
	  	}

		//  Draw the background
		offscreen.setColor(new Color(bkgdr, bkgdg, bkgdb));
		offscreen.fillRect(0,0,d.width, d.height);

		//  Print Text at top of Box
		offscreen.setColor(new Color (255-bkgdr, 255-bkgdg, 255-bkgdb));
		offscreen.setFont(titlefont);
		FontMetrics fm = offscreen.getFontMetrics();
		int titlewidth = fm.stringWidth(title);
		offscreen.drawString(title, (d.width-titlewidth)/2, titlefont.getSize());
		offscreen.drawLine (0, titlefont.getSize() +10, d.width, titlefont.getSize()+10);
				
		//  Motion for star polygon.  When "falling star"
		//  reaches bottom of applet box, restart at 
		//  random position along the top of the box.

		p.translate(dx,dy);
		rp = p.getBounds();
		if (rp.y >= d.height){
			rnd = (int)(Math.random() * (d.width/rp.width));
			shift = rnd * rp.width;
			Polygon q = new Polygon(polyx, polyy, polypoints);
			q.translate(shift,titlefont.getSize()+20);
			p = q;	
		}	
	
		//  Draw filled star Polygon
		offscreen.setColor(new Color (red,green,blue));
		offscreen.fillPolygon(p);
		offscreen.setColor(new Color(255,255,255));
		offscreen.drawPolygon(p);

		//  Motion for 3DRectangle 
		if (r.x < 10 || (r.x + r.width > d.width - 10)){
			dxrect = -dxrect;
			rgfh = -rgfh;
			rgfw = -rgfw;
		}

		if (r.y < titlefont.getSize() + 20 || r.y + r.height > 
			d.height - 10){
			dyrect = -dyrect;
			rgfh = -rgfh;
			rgfw = -rgfw;
		}
		r.x += dxrect;
		r.y += dyrect;
		r.height += rgfh;
		r.width += rgfw;
		
		if (r.height < 5 || r.height > d.height *.25) {
			rgfh = -rgfh;
			r.height +=rgfh;
		}

		if (r.width < 5 || r.width > d.width *.25) {
			rgfw = -rgfw;
			r.width += rgfw;
		}

		//  Draw 3DRectangle (outline)
		offscreen.setColor(new Color(red,green,blue));
		offscreen.draw3DRect(r.x, r.y, r.width, r.height, true);
		
		//  Copy offscreen image to the screen

		//  If "falling star" caught by box, print out "caught"
		//  phrase, draw inmage to screen and pause thread then 
		//  restart pathway of star from top at new position

		if ((rp.x>= r.x) &&  (rp.y >= r.y) && (rp.x + rp.width <= r.x + r.width) 
			&& (rp.y + rp.height <= r.y + r.height)){
			rnd = (int)(Math.random() * (d.width/rp.width));
			shift = rnd * rp.width;
			Polygon q = new Polygon(polyx, polyy, polypoints);
			q.translate(shift,0);
			p = q;
			offscreen.setColor(new Color (255-bkgdr, 255-bkgdg, 255-bkgdb));
			offscreen.setFont(caughtfont);
			offscreen.drawString(caught, r.x, r.y+r.height+caughtfont.getSize());
			g.drawImage (image, 0,0, this);
			try {
				Thread.currentThread().sleep(1000);
      			} catch (InterruptedException e){}
	
		}
		else {	
		g. drawImage (image, 0,0, this);
		}
	}

	public void paint (Graphics g){
		update(g);
	}

	//  The animation applet idiom
	protected Thread movingThread;
	protected int delay = 100;

	public void start(){
		movingThread = new Thread(this);
		movingThread.start();
	}

	public void stop(){
		movingThread = null;
	}

	public void run(){
		while (Thread.currentThread() == movingThread) {
			try {
				Thread.currentThread().sleep(delay);
			} catch (InterruptedException e){}
			repaint();
		}
	}
}