parallax planet

(function(){
$(document).ready(function(){
    PoormanParallax = function PoormanParallax(){
        //parallax
        this.body = body = $('body.breezi');
        this.viewPortH = window.innerHeight;
        this.bodyH = document.body.clientHeight;
        this.scroll = document.body.scrollTop;
        this.availableScroll = this.bodyH - this.viewPortH;
        this.backgroundScroll = 200;

        this.getProportions = function getProportions(scroll, availableSpace){
             return (scroll/availableSpace);
        };

        this.parallaxThatBitch = function parallaxThatBitch(){
            this.scroll = document.body.scrollTop;
            this.setVertBkndPos(this.body, this.getProportions(this.scroll, this.availableScroll), this.backgroundScroll);

            this.parallaxThemStars();
        };

        this.setVertBkndPos = function setVertBkndPos(element, position, availableSpace){
            var pos = (position*availableSpace),
                finalPos = (pos.toFixed(0)*-1),
                posString = '0% '+finalPos+'px';
            element.css('background-position', posString);
        };

        //planet and stars

        this.planetEl = $("[src*='planet']");
        this.planetContainer = this.planetEl.parent();
        this.topParent = this.planetContainer.parent();

        var containerH = this.topParent.height(),
            containerW = this.topParent.width(),
            celestialBodyTmpl = '<div style="position:absolute; top:0; left:0; height:'+containerH+'px; width:'+containerW+'px; background-repeat:no-repeat;"></div>',
            frontDelta = 50,
            middleDelta = 20,
            backDelta = -100;

            frontInt = -4;
            middleInit = -4;
            backInit = 1.5;


        this.starFrontUrl ='http://imgur.com/dj9mvy3.png';
        this.startBackUrl = 'http://imgur.com/ibUF0Xp.png';
        this.planetUrl = this.planetEl.attr('src');

        this.starFrontEl = $(celestialBodyTmpl);
        this.planetMiddleEl = $(celestialBodyTmpl);
        this.starBackEl = $(celestialBodyTmpl);

        this.planetContainer.remove();

        this.topParent.append(this.starBackEl);
        this.topParent.append(this.planetMiddleEl);
        this.topParent.append(this.starFrontEl);

        this.topParent.css({
            'width' : containerW,
            'height' : containerH,
            'position' : 'relative',
            'overflow' : 'hidden'
        });

        this.setupStars = function setupStars(){
            this.setBackground(this.starFrontEl, this.starFrontUrl);
            this.setBackground(this.planetMiddleEl, this.planetUrl);
            this.setBackground(this.starBackEl, this.startBackUrl);

            this.setVertBkndPos(this.starFrontEl, frontInt, frontDelta);
            this.setVertBkndPos(this.planetMiddleEl, middleInit, middleDelta);
            this.setVertBkndPos(this.starBackEl, backInit, backDelta);

            this.starFrontEl.css('left', '20%');
            this.planetMiddleEl.css('left', '40%');
            this.starBackEl.css('left', '70%');
        };

        this.setBackground = function setBackground(el, url){
            el.css('background-image', 'url('+url+')');
        };

        this.parallaxThemStars = function parallaxThemStars(){
            this.setVertBkndPos(this.starFrontEl, frontInt-this.getProportions(this.scroll, this.availableScroll), frontDelta);
            this.setVertBkndPos(this.planetMiddleEl, middleInit-this.getProportions(this.scroll, this.availableScroll), middleDelta);
            this.setVertBkndPos(this.starBackEl, backInit-this.getProportions(this.scroll, this.availableScroll), backDelta);
        };

        return this;
    };

    window.poormanParallax = new PoormanParallax();
    window.poormanParallax.setupStars();

    $(window).scroll(function(){
        window.poormanParallax.parallaxThatBitch();
    });
});
})();