var $ = require('jquery');

​

​

$(document).ready(() => {

jsCanvasSnow.init();

jsCanvasSnow.start();

}, false);

​

function jsParticle(origin, velocity, size, amplitude) {

this.origin = origin;

this.position = new Vector2(origin.x, origin.y);

this.velocity = velocity || new Vector2(0, 0);

this.size = size;

this.amplitude = amplitude;

​

this.dx = Math.random() * 100;

this.update = function(delta_time) {

this.position.y = this.velocity.y * delta_time;

this.dx = this.velocity.x * delta_time;

this.position.x = this.origin.x * (this.amplitude * Math.sin(this.dx));

};

}

​

var jsCanvasSnow =

{

canvas : null,

ctx : null,

particles : \[\],

running : false,

​

start\_time : 0,

frame\_time : 0,

​

init : function( )

{

    // use the container width and height

    this.canvas = document.getElementById('particle\_canvas');

    this.ctx = this.canvas.getContext('2d');

this.resize(window.innerWidth, window.innerHeight);

​

    // change these values

// the 2 element arrays represent min and max values

    this.pAmount = 5000;         // amount of particles

    this.pSize = \[0.5 , 1.5\];    // min and max size

    this.pSwing = \[0.1, 1\];      // min and max oscilation speed for x movement

    this.pSpeed = \[40, 100\],     // min and max y speed

    this.pAmplitude = \[25, 50\];  // min and max distance for x movement

​

this._init_particles();

},

​

start : function()

{

    this.running = true;

    this.start\_time = this.frame\_time = microtime();

    this.\_loop();

},

​

stop : function()

{

    this.running = false;

},

​

resize : function(w, h)

{

this.canvas.width = w;

this.canvas.height = h;

},

​

\_loop : function()

{

    if ( jsCanvasSnow.running )

    {

        jsCanvasSnow.\_clear();

        jsCanvasSnow.\_update();

        jsCanvasSnow.\_draw();

        jsCanvasSnow.\_queue();

    }

},

​

\_init\_particles : function()

{

    // clear the particles array

    this.particles.length = 0;

​

    for ( var i = 0 ; i < this.pAmount ; i  )

    {

        var origin = new Vector2(frand(0, this.canvas.width), frand(-this.canvas.height, 0));

        var velocity = new Vector2(frand(this.pSwing\[0\],this.pSwing\[1\]), frand(this.pSpeed\[0\],this.pSpeed\[1\]));

        var size = frand(this.pSize\[0\], this.pSize\[1\]);

        var amplitude = frand(this.pAmplitude\[0\], this.pAmplitude\[1\]);

​

        this.particles.push(new jsParticle(origin, velocity, size, amplitude));

    }

},

​

\_update : function()

{

    // calculate the time since the last frame

    var now\_time = microtime();

    var delta\_time = now\_time - this.frame\_time;

​

    for ( var i = 0 ; i < this.particles.length ; i  )

    {

        var particle = this.particles\[i\];

        particle.update(delta\_time);

​

        if (particle.position.y-particle.size > this.canvas.height)

        {

// reset the particle to the top and a random x position

particle.position.y = -particle.size;

particle.position.x = particle.origin.x = Math.random() * this.canvas.width;

particle.dx = Math.random() * 100;

        }

    }

​

    // save this time for the next frame

    this.frame\_time = now\_time;

},

​

\_draw : function()

{

    this.ctx.fillStyle = 'rgb(255,255,255)';

​

    for ( var i = 0 ; i < this.particles.length ; i  )

    {

        var particle = this.particles\[i\];

        this.ctx.fillRect(particle.position.x, particle.position.y, particle.size, particle.size);

    }

},

​

\_clear : function()

{

    this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);

},

​

\_queue : function()

{

    window.requestAnimationFrame( jsCanvasSnow.\_loop );

}

};