var current_image_number = 1;
var next_image_number;
var number_of_images = 4;
var fade_step;
var fade_timer = 0;

function image_loaded()
{
	var fade_image;

	next_image_number = current_image_number + 1;

	if ( next_image_number > number_of_images )
	{
		next_image_number = 1;
	}

	fade_image = document.getElementById( 'home_image_fade' );

	fade_image.style.visibility = 'hidden';
	fade_image.src = 'images/home' + next_image_number + '.jpg';
}

function start_image_cycle()
{
	window.setInterval( 'start_fade()', 4000 );
}

function start_fade()
{
	fade_step = 0;
	fade_timer = window.setInterval( 'on_fade_timer()', 50 );
}

function on_fade_timer()
{
	var fade_image;
	var background_image;

	if ( fade_step >= 100 )
	{
		window.clearInterval( fade_timer );
		fade_timer = 0;

		current_image_number = next_image_number;

		background_image = document.getElementById( 'home_image_main' );

		background_image.src = 'images/home' + current_image_number + '.jpg';
	}
	else
	{
		fade_step += 5;

		fade_image = document.getElementById( 'home_image_fade' );

		set_opacity( fade_image, fade_step );
	}
}