Użytkownik:SH3VEK/common.js

// KOD NA ŚNIEG
(function() {
    'use strict';
    var NUM_FLAKES = 40;
    var flakes, Flake, PI_2, canvas, context, drawCircle, i, range, resizeWindow, xpos;
    PI_2 = 2 * Math.PI;
    canvas = $('<canvas style="z-index: 500; pointer-events: none; position: fixed; top: 0; left: 0;" id="snieg"></canvas>').appendTo("body")[0];
    context = canvas.getContext("2d");
    window.w = 0;
    window.h = 0;
    resizeWindow = function() {
        window.w = canvas.width = window.innerWidth;
        return (window.h = canvas.height = window.innerHeight);
    };
    window.addEventListener('resize', resizeWindow, false);
    $(function() {return setTimeout(resizeWindow, 0);});
    range = function(a, b) {return (b - a) * Math.random() + a;};
    drawCircle = function(x, y, r) {
        context.beginPath();
        context.arc(x, y, r, 0, PI_2, false);
        context.fill();
        context.stroke();
    };
    xpos = 0.5;
    document.onmousemove = function(e) {return (xpos = e.pageX / w);};
    window.requestAnimationFrame = (function() {
        return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function(callback) {
            return window.setTimeout(callback, 1000 / 60);
        };
    })();
    Flake = (function() {
        function Flake() {
            this.r = ~~range(4, 8);
            this.r2 = 2 * this.r;
            this.replace();
        }
        Flake.prototype.replace = function() {
            this.x = range(-this.r2, w - this.r2);
            this.y = range(-20, h - this.r2);
            this.xmax = w - this.r;
            this.ymax = h - this.r;
            this.vx = range(0, 2) + 8 * xpos - 5;
            this.vy = 0.5 * this.r + range(-0.5, 0.5);
        };
        Flake.prototype.draw = function() {
            var f;
            this.x += this.vx;
            this.y += this.vy;
            if (this.y > this.ymax) {
                this.replace();
            }
            if (!((0 < (f = this.x) && f < this.xmax))) {
                this.x = (this.x + this.xmax) % this.xmax;
            }
            drawCircle(~~this.x, ~~this.y, this.r);
        };
        return Flake;
    })();
    flakes = (function() {
        var i, a = [];
        for (i = 0; i < NUM_FLAKES; i++)
            a.push(new Flake());
        return a;
    })();
    window.step = function() {
        var i, len;
        requestAnimationFrame(step);
        context.clearRect(0, 0, w, h);
        context.fillStyle = "rgba(255,255,255,1)";
        context.lineWidth = 2;
        context.strokeStyle = "rgba(0,0,0,0.25)";
        for (i = 0, len = flakes.length; i < len; i++)
            flakes[i].draw();
    };
    step();
    console.log("Załadowano śnieg");
})();