asset loading

asset loading

Loader=function()//asset-loading system
{
	this.loadingN=0;
	this.assetsN=0;
	this.assets=[];
	this.assetsLoading=[];
	this.assetsLoaded=[];
	this.domain='';
	this.loaded=0;//callback
	this.doneLoading=0;
	
	this.blank=document.createElement('canvas');
	this.blank.width=8;
	this.blank.height=8;
	this.blank.alt='blank';

	this.Load=function(assets)
	{
		for (var i in assets)
		{
			this.loadingN++;
			this.assetsN++;
			if (!this.assetsLoading[assets[i]] && !this.assetsLoaded[assets[i]])
			{
				var img=new Image();
				img.src=this.domain+assets[i];
				img.alt=assets[i];
				img.onload=bind(this,this.onLoad);
				this.assets[assets[i]]=img;
				this.assetsLoading.push(assets[i]);
			}
		}
	}
	this.Replace=function(old,newer)
	{
		if (this.assets[old])
		{
			var img=new Image();
			if (newer.indexOf('http')!=-1) img.src=newer;
			else img.src=this.domain+newer;
			img.alt=newer;
			img.onload=bind(this,this.onLoad);
			this.assets[old]=img;
		}
	}
	this.onLoadReplace=function()
	{
	}
	this.onLoad=function(e)
	{
		this.assetsLoaded.push(e.target.alt);
		this.assetsLoading.splice(this.assetsLoading.indexOf(e.target.alt),1);
		this.loadingN--;
		if (this.doneLoading==0 && this.loadingN<=0 && this.loaded!=0)
		{
			this.doneLoading=1;
			this.loaded();
		}
	}
	this.getProgress=function()
	{
		return (1-this.loadingN/this.assetsN);
	}
}