// ==UserScript==
// @name       Snow generator
// @namespace  http://use.i.E.your.homepage/
// @version    2.0
// @description  Enhances fp with snow
// @require   http://code.jquery.com/jquery-1.10.2.min.js
// @require		https://raw.github.com/mrdoob/three.js/master/build/three.min.js
// @match      http://*/*
// @match		https://*/*
// @copyright  2012+, Sander
// ==/UserScript==


Particle3D = function (material ) {
	THREE.Particle.call( this, material );
	this.velocity = new THREE.Vector3(0,-8,0);
	this.velocity.rotateX(randomRange(-45,45)); 
	this.velocity.rotateY(randomRange(0,360)); 
	this.gravity = new THREE.Vector3(0,0,0); 
	this.drag = 1; 
};

Particle3D.prototype = new THREE.Particle();
Particle3D.prototype.constructor = Particle3D;

Particle3D.prototype.updatePhysics = function() {
	this.velocity.multiplyScalar(this.drag); 
	this.velocity.add(this.gravity);
	this.position.add(this.velocity);
}

var TO_RADIANS = Math.PI/180; 

THREE.Vector3.prototype.rotateY = function(angle){					
	cosRY = Math.cos(angle * TO_RADIANS);
	sinRY = Math.sin(angle * TO_RADIANS);
	
	var tempz = this.z;; 
	var tempx = this.x; 

	this.x= (tempx*cosRY)+(tempz*sinRY);
	this.z= (tempx*-sinRY)+(tempz*cosRY);
}

THREE.Vector3.prototype.rotateX = function(angle){			
	cosRY = Math.cos(angle * TO_RADIANS);
	sinRY = Math.sin(angle * TO_RADIANS);
	
	var tempz = this.z;; 
	var tempy = this.y; 

	this.y= (tempy*cosRY)+(tempz*sinRY);
	this.z= (tempy*-sinRY)+(tempz*cosRY);
}

THREE.Vector3.prototype.rotateZ = function(angle){
	cosRY = Math.cos(angle * TO_RADIANS);
	sinRY = Math.sin(angle * TO_RADIANS);
	
	var tempx = this.x;; 
	var tempy = this.y; 

	this.y= (tempy*cosRY)+(tempx*sinRY);
	this.x= (tempy*-sinRY)+(tempx*cosRY);
}

// returns a random number between the two limits provided 
function randomRange(min, max)
{
	return ((Math.random()*(max-min)) + min); 
}

var SCREEN_WIDTH = window.innerWidth;
var SCREEN_HEIGHT = window.innerHeight;
var container;
var RotTime =0;
var particle;
var camera;
var scene;
var renderer;
var windowHalfX = window.innerWidth / 2;
var windowHalfY = window.innerHeight / 2;

var particles = []; 
var particleImage = new Image();//THREE.ImageUtils.loadTexture( "img/ParticleSmoke.png" );
particleImage.src = 'http://i.imgur.com/HW1dbP4.png'; 

function initSnow() {
    camera = new THREE.PerspectiveCamera( 60, SCREEN_WIDTH / SCREEN_HEIGHT, 1, 10000 );
    camera.position.z = 400;
    scene = new THREE.Scene();
    scene.add(camera);
    renderer = new THREE.CanvasRenderer();
    renderer.setSize(SCREEN_WIDTH, SCREEN_HEIGHT);
    var material = new THREE.ParticleBasicMaterial( { map: new THREE.Texture(particleImage) } );
    
    for (var i = 0; i < 200; i++) {
        
        particle = new Particle3D( material);
        particle.position.x = Math.random() * 1000 - 500;
        particle.position.y = Math.random() * 2000 - 1000;
        particle.position.z = Math.random() * 1000 - 500;
        particle.velocity = new THREE.Vector3(0,-1,0);
        particle.scale.x = particle.scale.y =  10.0;
        scene.add( particle );
        particles.push(particle); 
    }
    
    document.body.appendChild( renderer.domElement );
    setInterval( loop, 1000 / 25 );
    
    $("CANVAS").css("z-index", 1000);
    $("CANVAS").css("position", "fixed");
    $("CANVAS").css("left", 0);
    $("CANVAS").css("top", 0);
    $("CANVAS").css("right", 0);
    $("CANVAS").css("bottom", 0);
    $("CANVAS").css("pointer-events", "none");
}

function loop() {
    for(var i = 0; i<particles.length; i++)
    {
        var particle = particles[i]; 
        particle.updatePhysics(); 
        
        with(particle.position)
        {
            
            if(y<-1000) y+=2000; 
            if(x>500) x-=1000; 
            else if(x<-500) x+=1000; 
            if(z>500) z-=1000; 
            else if(z<-500) z+=1000; 
        }
    }
    
    RotTime = RotTime + 0.004;
    camera.position.x = Math.sin( RotTime ) * 400;
    camera.position.z = Math.cos( RotTime  ) * 400;
    camera.lookAt(scene.position); 
    renderer.render( scene, camera );
}

$(function() {
    if(('pointerEvents' in document.body.style)) 
    {
        initSnow();
    }
});