// Simple Crossfade by Chris Shrigley.
// This crossfade will pick a random initial picture and fade it in from "blank".
// Subsequent fades will cross fade with the alternating DIV, initialized in initCross.

var Pic = new Array();
Pic[0] = 'gfx/banner1.jpg';
Pic[1] = 'gfx/banner2.jpg';
Pic[2] = 'gfx/banner3.jpg';
Pic[3] = 'gfx/banner4.jpg';
Pic[4] = 'gfx/banner5.jpg';
Pic[5] = 'gfx/banner6.jpg';
Pic[6] = 'gfx/banner7.jpg';
Pic[7] = 'gfx/banner8.jpg';
Pic[8] = 'gfx/banner9.jpg';
Pic[9] = 'gfx/banner10.jpg';
Pic[10] = 'gfx/banner11.jpg';
Pic[11] = 'gfx/banner12.jpg';
Pic[12] = 'gfx/banner13.jpg';
Pic[13] = 'gfx/banner14.jpg';
Pic[14] = 'gfx/banner15.jpg';
Pic[15] = 'gfx/banner16.jpg';
Pic[16] = 'gfx/banner17.jpg';
Pic[17] = 'gfx/banner18.jpg';
Pic[18] = 'gfx/banner19.jpg';
Pic[19] = 'gfx/banner20.jpg';
Pic[20] = 'gfx/banner21.jpg';
var numpics = Pic.length;

var tran_speed = 15000;		// 5 secs
var fade_speed = 100;		// 10th sec

var cf1;
var cf2;

var fpicidx = 0;
var fval = 100;
var fvstep = 5;
var fvdir = 0;

var again;
var idx;

// Preload the images
var preLoad = new Array();
for (idx=0; idx<numpics; idx++) {
	preLoad[idx] = new Image();
	preLoad[idx].src = Pic[idx];
}

function initCross()
{
	// Get the DIV objects
	cf1 = document.getElementById('cf1');
	cf2 = document.getElementById('cf2');
	
	if (cf1 && cf2)
	{
		// Set the timeout events
		setTimeout('initCross()', tran_speed);
		setTimeout('doCross()', fade_speed);

		// Random starting pic
		fpicidx = Math.round((numpics-1) * Math.random());
		if (fvdir)
			cf1.style.backgroundImage = 'url(' + Pic[fpicidx] + ')';
		else
			cf2.style.backgroundImage = 'url(' + Pic[fpicidx] + ')';

		// Set initial opacities
		setOpacity(fval);
	}
}

function doCross()
{
	if (cf1 && cf2)
	{
		// Fade
		again = 1;
		if (fvdir) {
			fval += fvstep;
			if (fval > 100)
			{
				fval = 100;
				again = 0;
			}
		} else {
			fval -= fvstep;
			if (fval < 0) {
				fval = 0;
				again = 0;
			}
		}
		
		// Set opacities
		setOpacity(fval);
		
		// Done or not?
		if (again)
			setTimeout('doCross()', fade_speed);
		else
			fvdir ^= 1;
	}
}

// Set the DIV opacities
function setOpacity(opacity)
{
	if (cf1 && cf2)
	{
		cf1.style.opacity = opacity / 100;
//		cf1.style.-moz-opacity = opacity / 100;
		cf1.style.filter = "alpha(opacity='" + opacity + "')";
		cf2.style.opacity = (100-opacity) / 100;
//		cf2.style.-moz-opacity = (100-opacity) / 100;
		cf2.style.filter = "alpha(opacity='" + (100-opacity) + "')";
	}
}