/*

  SparkSet Classes

  Written by rryu <rryu@t3.rim.or.jp>
             http://www.t3.rim.or.jp/~rryu/

  # 2001-08-31 Ver 1.0

*/

//----------------------------------------------------
// Spark class definition
//

function Spark(elem,weight)
{
	this.elem = elem;
	this.weight = (weight == 0) ? 10 : weight;
	this.x = 0;
	this.y = 0;
	this.speedX = 0;
	this.speedY = 0;
	this.lifetime = 0;
	this.isLive = false;

	this.setVisible(false);

	elem.onmousedown = Spark_eventIgnore;
	elem.onmouseup = Spark_eventIgnore;
	elem.onmouseover = Spark_eventIgnore;
	elem.onmouseout = Spark_eventIgnore;
	elem.onmousemove = Spark_eventIgnore;
}

function Spark_eventIgnore()
{
	return true;
}

function Spark_birth(startX,startY,spX,spY,lifetime)
{
	this.x = startX;
	this.y = startY;
	this.speedX = spX;
	this.speedY = spY;
	this.lifetime = lifetime;
	this.isLive = true;

	this.moveTo(startX,startY);
	this.setVisible(true);
}

function Spark_die()
{
	this.setVisible(false);
	this.isLive = false;
}

function Spark_doMove()
{
	this.x += this.speedX;
	this.y += this.speedY;
	this.moveTo(this.x,this.y);
	this.speedY += this.weight;
	this.lifetime--;
	if (this.lifetime <= 0) this.die();
	return this.isLive;
}

function Spark_moveTo_IE(x,y)
{
	this.elem.style.left = "" + Math.round(x) + "px";
	this.elem.style.top = "" + Math.round(y) + "px";
}

function Spark_moveTo_Netscape(x,y)
{
	this.elem.left = x;
	this.elem.top = y;
}

function Spark_setVisible_IE(isVisible)
{
	this.elem.style.visibility = (isVisible) ? "visible" : "hidden";
}

function Spark_setVisible_Netscape(isVisible)
{
	this.elem.visibility = (isVisible) ? "visible" : "hide";
}


Spark.prototype.birth = Spark_birth;
Spark.prototype.die = Spark_die;
Spark.prototype.doMove = Spark_doMove;

if (document.layers){
	Spark.prototype.moveTo = Spark_moveTo_Netscape;
	Spark.prototype.setVisible = Spark_setVisible_Netscape;
}else{
	Spark.prototype.moveTo = Spark_moveTo_IE;
	Spark.prototype.setVisible = Spark_setVisible_IE;
}

//----------------------------------------------------
// SparkSet class definition
//

function SparkSet(id,interval,weight)
{
	this.sparks = new Array();
	this.numSpark = 0;
	this.numLiveSpark = 0;
	this.birthIdx = 0;
	this.interval = interval;
	this.isSetTimeout = false;
	this.sparkWeight = weight;
	this.id = id;
    SparkSet.instances[id] = this;
}

function SparkSet_getElementById(id)
{
	return document.getElementById(id);
}

function SparkSet_getElemetById_IE(id)
{
	return document.all[id];
}

function SparkSet_getLayerById(id)
{
	return document.layers[id];
}

function SparkSet_start(n)
{
	var elem;
	this.sparks = new Array();
	for (var i = 0; i < n; i++){
		elem = this.getElementById(this.id + i);
		this.sparks[i] = new Spark(elem,this.sparkWeight);
	}
	this.numSpark = n;
	this.numLiveSpark = 0;
}

function SparkSet_startWithWriteElements(n,imgFile,imgWidth,imgHeight,spread)
{
	for(var i = 0; i < n; i++){
		var delta = Math.floor(spread * Math.random());
		var w = imgWidth - delta;
		var h = imgHeight - delta;
		this.writeSparkElement(i,imgFile,w,h);
	}
	this.start(n);
}

function SparkSet_WriteSparkElement(no,imgFile,imgWidth,imgHeight)
{
	document.write('<DIV id="' + this.id + no + '" style="position:absolute; visibility: hidden;">');
	document.write('<IMG src="' + imgFile + '" width="' + imgWidth + '" height="' + imgHeight + '">');
	document.write('</DIV>');
}

function SparkSet_WriteSparkLayer(no,imgFile,imgWidth,imgHeight)
{
	document.write('<LAYER name="' + this.id + no + '" visibility="hide">');
	document.write('<IMG src="' + imgFile + '" width="' + imgWidth + '" height="' + imgHeight + '">');
	document.write('</LAYER>');
}

function SparkSet_birthSpark(x,y,spX,spY,lifetime)
{
	if (this.numLiveSpark >= this.numSpark) return false;

	while (this.numLiveSpark < this.numSpark){
		var spark = this.sparks[this.birthIdx++];
		if (this.birthIdx >= this.numSpark) this.birthIdx = 0;
		if (!spark.isLive){
			spark.birth(x,y,spX,spY,lifetime);
			this.numLiveSpark++;
			break;
		}
	}

	if (this.numLiveSpark > 0 && !this.isSetTimeout) this.setTimeout();
	return true;
}

function SparkSet_setTimeout()
{
    setTimeout('SparkSet.instances["' + this.id + '"].doSpark()',this.interval);
	this.isSetTimeout = true;
}

function SparkSet_doSpark()
{
	for(var i = 0; i < this.numSpark; i++){
		var spark = this.sparks[i];
		if (spark.isLive){
			if (!spark.doMove()) this.numLiveSpark--;
		}
	}

	this.isSetTimeout = false;
	if (this.numLiveSpark > 0) this.setTimeout();
}

SparkSet.instances = new Object();

if (document.getElementById){
	SparkSet.prototype.getElementById = SparkSet_getElementById;
	SparkSet.prototype.writeSparkElement = SparkSet_WriteSparkElement;
}else if (document.layers){
	SparkSet.prototype.getElementById = SparkSet_getLayerById;
	SparkSet.prototype.writeSparkElement = SparkSet_WriteSparkLayer;
}else{
	SparkSet.prototype.getElementById = SparkSet_getElemetById_IE;
	SparkSet.prototype.writeSparkElement = SparkSet_WriteSparkElement;
}
SparkSet.prototype.start = SparkSet_start;
SparkSet.prototype.startWithWriteElements = SparkSet_startWithWriteElements;
SparkSet.prototype.birthSpark = SparkSet_birthSpark;
SparkSet.prototype.setTimeout = SparkSet_setTimeout;
SparkSet.prototype.doSpark = SparkSet_doSpark;