/*
	Javascript for animating birds-images 
*/
	var x = new Array(-100,-140,-120);
	var y = new Array(10,5,14);
	var vx = new Array(1,1,0.8);
	var vy = new Array(0,0,0);
	var startPosX = 100;
	var startPosY = 15;
	var numBirds = 3;
	var birds=new Array(numBirds);
	
	
	function startScript()
	{
		birds[0]=document.getElementById("bird0");
		birds[1]=document.getElementById("bird1");
		birds[2]=document.getElementById("bird2");
		setInterval ( "animateBirds()", 25 );
	}
	
	function animateBirds()
	{
		var ax = new Array(numBirds);
		var ay = new Array(numBirds);

		for(i=0;i<numBirds;i++)
		{
			ax[i]=0;
			ay[i]=0;
		}
		
		
		//vx[0]=vx[0]+(Math.random()-0.5)/10;
		
		for(b=0;b<numBirds;b++) 
		{
			for(i=0;i<numBirds;i++)
			{
				if(b!=i)
				{
					ax[b]+=(x[i]-x[b]-20)/5000;
					ay[b]+=(y[i]-y[b])/8000;
				}
			}
			vx[b]+=ax[b];
			vy[b]+=ay[b];
	
				if(vx[b]<(vx[0]/2))
				{
					vx[b]=vx[0]/2;
				}
		}
		vx[0]=1;
		
		for(b=0;b<numBirds;b++) 
		{
			x[b]=x[b]+vx[b];
			birds[b].style.posLeft = startPosX + x[b] + findPosX(document.getElementById("container"));
			y[b]=y[b]+vy[b];
			birds[b].style.posTop = startPosY + y[b];
		}
		if(x[0]>900)
		{
			for(b=0;b<numBirds;b++) 
			{
				x[b]-=1000;
			}
		}
	}
	
	function findPosX(obj)
  	{
    var curleft = 0;
    if(obj.offsetParent)
        while(1) 
        {
          curleft += obj.offsetLeft;
          if(!obj.offsetParent)
            break;
          obj = obj.offsetParent;
        }
    else if(obj.x)
        curleft += obj.x;
    return curleft;
  	}