//********************************************************************************
// Spangler.java
//
// (c) 1998 Maeda Mameo     http://hw001.gate01.com/frog/
//********************************************************************************



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

	private int appW, appH;
	private java.awt.Image imageIt, imageOff;
	private java.awt.Graphics gOff;
	private Thread threadIt;

	static final int MAXDUSTNUM = 100;
	private int dustState[] = new int[MAXDUSTNUM];
	private int dustMaxSize[] = new int[MAXDUSTNUM];
	private int dustSize[] = new int[MAXDUSTNUM];
	private int dustX[] = new int[MAXDUSTNUM];
	private int dustY[] = new int[MAXDUSTNUM];
	private java.awt.Color dustColor;
	
	private double dustMagnification, dustDensity;

	private boolean isFPS;
	private int timeMillisPointer;
	static final int TIMEMILLISNUM = 50;
	private long[] latestTimeMillis = new long[TIMEMILLISNUM];



//********************************************************************************
//********************************************************************************



	public void init(){
		String s;
		java.awt.Dimension d;
		
		d = size();
		appW = d.width;
		appH = d.height;
		imageOff = createImage( appW, appH);
		gOff = imageOff.getGraphics();

		imageIt = getImage( getDocumentBase(), getParameter("image"));

		s = getParameter("size");
		if( s == null) s = "5";
		dustMagnification = (double)Integer.parseInt(s) / 5;
		if( dustMagnification <= 0 || dustMagnification > 2) dustMagnification = 1;
		dustMagnification = Math.pow( dustMagnification, 1.5);

		s = getParameter("density");
		if( s == null) s = "5";
		dustDensity = (double)Integer.parseInt(s) / 5;
		if( dustDensity <= 0 || dustDensity > 2) dustMagnification = 1;

		s = getParameter("color");
		if( s == null) s = "ffff00";
		dustColor = new java.awt.Color( Integer.parseInt( s, 16));

		isFPS = false;
	}

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

    public void stop(){ threadIt.stop(); threadIt = null;}

    public void update( java.awt.Graphics g){ paint(g);}

    public void paint( java.awt.Graphics g){
		gOff.drawImage( imageIt, 0, 0, this);
		drawDust();
		g.drawImage( imageOff, 0, 0, this);
	}

	public boolean mouseEnter( java.awt.Event e, int x, int y){
		isFPS = true;
		return true;
	}

	public boolean mouseExit( java.awt.Event e, int x, int y){
		isFPS = false;
		showStatus(null);
		return true;
	}


//********************************************************************************
//********************************************************************************

    public void run(){
		int i;
		double a;
		long t;

		resetDust();

		timeMillisPointer = 0;
		latestTimeMillis[0] = System.currentTimeMillis();
		for( i = 1; i < TIMEMILLISNUM; i++) latestTimeMillis[i] = 0;

		while(true){
			if( Math.random() < .2 * dustDensity) addDust( (int)( Math.random() * appW), (int)( Math.random() * appH));

			repaint();
			sleeper(17);

			while(( t = System.currentTimeMillis()) - latestTimeMillis[timeMillisPointer] < 1000 / 20) sleeper(1);

			timeMillisPointer = ++timeMillisPointer % TIMEMILLISNUM;
			if(isFPS) showStatus( "" + ( (double)( 1000 * 1000 * TIMEMILLISNUM / ( t - latestTimeMillis[timeMillisPointer])) / 1000) + " frames/sec.");
			latestTimeMillis[timeMillisPointer] = t;
		}
	}

	private void resetDust(){
		int i;

		for( i = 0; i < MAXDUSTNUM; i++) dustState[i] = 0;
	}

	private void addDust( int x, int y){
		int i;

		for( i = 0; i < MAXDUSTNUM; i++) if( dustState[i] == 0){
			dustX[i] = x;
			dustY[i] = y;
			dustMaxSize[i] = 10 + (int)( Math.random() * 30);
			dustSize[i] = 0;
			dustState[i] = 5;
			return;
		}
	}

	private void drawDust(){
		int a, b, c, i, x, y;
		java.awt.Polygon p;

		for( i = 0; i < MAXDUSTNUM; i++) if( dustState[i] != 0){
			dustSize[i] += dustState[i];
			if( dustSize[i] >= dustMaxSize[i]){
				dustSize[i] = dustMaxSize[i];
				dustState[i] = -1;
			}
			a = dustSize[i];

			if( a > 0){
				x = dustX[i];
				y = dustY[i];
				b = (int)( dustMagnification * a / 5);
				c = (int)( dustMagnification * a / 2);

				p = new java.awt.Polygon();
				p.addPoint( x, y - (int)( dustMagnification * 3 * a / 2));

				p.addPoint( x + b, y - c);
				p.addPoint( x + c, y - b);

				p.addPoint( x + (int)( dustMagnification * a), y);

				p.addPoint( x + c, y + b);
				p.addPoint( x + b, y + c);

				p.addPoint( x, y + (int)( dustMagnification * 3 * a / 2));

				p.addPoint( x - b, y + c);
				p.addPoint( x - c, y + b);

				p.addPoint( x - (int)( dustMagnification * a), y);

				p.addPoint( x - c, y - b);
				p.addPoint( x - b, y - c);

				gOff.setColor(dustColor);
				gOff.fillPolygon(p);
				gOff.drawLine( x, y - (int)( dustMagnification * 2 * a), x, y + (int)( dustMagnification * 2 * a));
				gOff.drawLine( x - (int)( dustMagnification * 5 * a / 4), y, x + (int)( dustMagnification * 5 * a / 4), y);

			} else dustState[i] = 0;
		}
	}

	private void sleeper( int t){ try Thread.sleep(t); catch( InterruptedException e);}
}