/*
	loader for backgrounds
	www.fliehkraft.com
	(c) FRIEBEL WV www.friebelwv.de
	(c) pixelfis.ch

	*needs two div: bg_loader_0 | bg_loader_1
	*needs PHP inits
	*check for file existence via PHP

*/

var bg_loader_img=new Array();
var handle_const="";
var handle_change="";
var bg_loader_max=0;

function bg_loader_init ( ) {

	if ( bg_loader_current <0 ) {
		bg_loader_max=bg_loader_file.length-1;
		handle_const=document.getElementById("bg_loader_0");
		handle_change=document.getElementById("bg_loader_1");
		handle_change.style.display="none";
		handle_const.style.zIndex=0;
		handle_change.style.zIndex=1;
		
		for ( var i=0; i<=bg_loader_max; i++ ) {
			bg_loader_img[i]=new Image();   bg_loader_img[i].src=bg_loader_file[i];
			bg_loader_state[i]=0;
		}
		
		bg_loader_current=0;
		bg_loader_prepare();
	}	
}

function bg_loader_next ( ) {
	bg_loader_current++;
	if ( bg_loader_current > bg_loader_max ) {
		bg_loader_current=0;
	}
	bg_loader_prepare();
}

function bg_loader_prepare ( ) {
	if ( bg_loader_img[bg_loader_current].complete ) {
		handle_change.style.background="blue url("+bg_loader_file[bg_loader_current]+") no-repeat top center";
		handle_const.style.zIndex=9;
		handle_change.style.zIndex=1;
		handle_const.style.zIndex=0;
		handle_change.style.opacity=0;
		handle_change.style.MozOpacity=0;
		handle_change.style.KhtmlOpacity=0;
		handle_change.style.filter="alpha(opacity=0)";
		handle_change.style.display="block";
		bg_loader_state[bg_loader_current]=0;	
		bg_loader_process(handle_const,handle_change);
		window.setTimeout("bg_loader_next()",bg_loader_duration*1000)
	} else {
		window.setTimeout("bg_loader_prepare()",100)
	}
}

function bg_loader_process ( ) {
	var loader_progress=bg_loader_state[bg_loader_current]+(100/bg_loader_swap_steps);
	if ( loader_progress >100 ) {
		loader_progress=100;
	}

	handle_change.style.opacity=loader_progress/100;
	handle_change.style.MozOpacity=loader_progress/100;
	handle_change.style.KhtmlOpacity=loader_progress/100;
	handle_change.style.filter="alpha(opacity="+loader_progress+")";
	bg_loader_state[bg_loader_current]=loader_progress;
	
	if ( loader_progress == 100 ) {
		handle_const.style.background="blue url("+bg_loader_file[bg_loader_current]+") no-repeat top center";
		handle_const.style.display="block";
		handle_change.style.display="none";
	} else {
		window.setTimeout("bg_loader_process()",bg_loader_swap_duration);	
	} 
}