/****************************************** 
* Titre:	De la neige !!!
* Réécrit par Spacefrog	
* Date: 	12/2009
******************************************/

var IsIE6 = (!!document.all && !window.XMLHttpRequest)
//var ext= (/(?!=compatible;\s)MSIE\s6/i.test(navigator.userAgent))?'gif':'png';
var ext = (IsIE6) ? 'gif' : 'png';

var IsIE = !!document.all;

var snowsrc = new Image();
snowsrc.src = "images/snowflake." + ext
var snowsrc1 = new Image;
snowsrc1.src = "images/snowflake1." + ext

// Configure below to change number of snow to render 
var densite = 50;



var dx, xp, yp;    // coordinate and position variables 
var am, vx, vy;  // amplitude and step variables 
var i, doc_width, doc_height;
var vitesseH = 1 //coefficient de vitesse de balancement
var changevent = true // pour ajouter la variation du sens et de l'intesité du vent
var vent = new Array(10, 0, -10, -20, 0, -5, -10, -5, -3, 0, 2, 3, 5, 10, 20, 30, 50, 60, 80, 70, 50, 30, 10, 0, -1, -5, -10, -20); //Vent de travers  positif=> G à D _ négatif => D à G.
var forceH = 0;
var drift = 10;

var changechute = true
var chute = new Array(1, 2, 3, 2, 1, 1, 2, 3, 4, 5, 4, 3, 5, 4, 6, 4, 2, 3, 2, 1, 1, 1, 1, 1, 1) //Vitesse de chute des flocons de 1 à 10
var forceV = 0
var vitesseV = 1 //coefficient de vitesse de chute

dx = new Array();
xp = new Array();
yp = new Array();
am = new Array();
vx = new Array();

function init() {
    if (self != parent) {
        document.body.parentNode.parentNode.firstChild.nodeValue = 'doctype HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"';
    }




    doc_width = (self != top) ? top.frames[0].document.body.offsetWidth : self.document.body.offsetWidth;
    doc_height = (self != top) ? top.frames[0].document.body.offsetHeight : self.document.body.offsetHeight;

    densite = Math.floor(doc_width / 12);


    var flake = document.createElement('img');
    flake.style.border = '0';
    flake.style.width = "auto";
    flake.style.height = "auto";
    flake.style.position = 'absolute';
    flake.style.top = '15px';
    flake.style.left = '15px';
    flake.style.display = "none";

    //Position des flocons
    var i = 0;
    while (i < densite) {
        dx[i] = 0;                        // set coordonnés variables 
        xp[i] = Math.random() * (doc_width - 50);  // positions variables 
        yp[i] = Math.random() * doc_height;
        am[i] = Math.random() * 40;         // amplitude de balancement 
        vx[i] = 0.02 + Math.random() / 10 * vitesseH; // vitesse horizontale variable 
        vy[i] = 0.9 + Math.random() * vitesseV;     // vitesse verticale variable 


        var opacite = Math.random() * 100;
        var newflake = flake.cloneNode(true);
        newflake.id = "flocon" + i;
        newflake.zIndex = i + 1;


        newflake.src = (i % 2 == 0) ? snowsrc.src : snowsrc1.src;
        if (!document.all) { newflake.style.height = 20 - (Math.floor((Math.random() * 8))) + "px" }
        IsIE ? newflake.style.filter = "alpha(opacity=" + opacite + ")" : newflake.style.opacity = opacite / 100;
        document.body.appendChild(newflake);
        i++
    }
    var neige = setInterval(function() { snow() }, 30);
    if (changevent == true) {
        var girouette = setInterval(wind, 4250);
    }
    if (changechute == true) {
        var intesite = setInterval(fall, 7130);
    }
}

function wind() {
    drift = vent[forceH]
    forceH++
    forceH = (forceH > vent.length) ? 0 : forceH;
}

function fall() {
    vitesseV = chute[forceV]
    forceV++
    forceV = (forceV > chute.length - 1) ? 0 : forceV;
}

function snow() {

    //doc_width = document.body.offsetWidth; 
    //doc_height = document.body.offsetHeight;  
    doc_width = (self != top) ? top.frames[0].document.body.offsetWidth : document.body.offsetWidth;
    doc_height = (self != top) ? top.frames[0].document.body.offsetHeight : document.body.offsetHeight;

    var i = 0;
    while (i < densite) {
        yp[i] += vy[i];
        if (yp[i] > doc_height - 20) {
            xp[i] = (Math.random() * (doc_width - am[i] - 30));
            yp[i] = 0;
            vx[i] = (0.02 + Math.random() / 10) * vitesseH;
            vy[i] = (0.7 + Math.random()) * vitesseV;
        }

        dx[i] += vx[i];
        document.getElementById("flocon" + i).style.display = "block"
        document.getElementById("flocon" + i).style.top = yp[i] + "px";
        if (drift > 0) {
            xp[i] = ((xp[i] + drift / 10) > doc_width) ? -40 : xp[i] + drift / 10;
        }
        if (drift < 0) {
            xp[i] = ((xp[i] + drift / 10) < -40) ? doc_width : xp[i] + drift / 10;
        }
        document.getElementById("flocon" + i).style.left = xp[i] + am[i] * Math.sin(dx[i]) + "px";
        i++
    }

}