Pen Settings

CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URL's added here will be added as <link>s in order, and before the CSS in the editor. If you link to another Pen, it will include the CSS from that Pen. If the preprocessor matches, it will attempt to combine them before processing.

+ add another resource

You're using npm packages, so we've auto-selected Babel for you here, which we require to process imports and make it all work. If you need to use a different JavaScript preprocessor, remove the packages in the npm tab.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

+ add another resource

Use npm Packages

We can make npm packages available for you to use in your JavaScript. We use webpack to prepare them and make them available to import. We'll also process your JavaScript with Babel.

⚠️ This feature can only be used by logged in users.

Code Indentation


Save Automatically?

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

HTML Settings

Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

<canvas id="canvas"></canvas>
              body {
	padding: 0;
	margin: 0;
	overflow: hidden;
              //Code by: Kushagra Agarwal

// RequestAnimFrame: a browser API for getting smooth animations
window.requestAnimFrame = (function(){
  return  window.requestAnimationFrame       || 
		  window.webkitRequestAnimationFrame || 
		  window.mozRequestAnimationFrame    || 
		  window.oRequestAnimationFrame      || 
		  window.msRequestAnimationFrame     ||  
		  function( callback ){
			window.setTimeout(callback, 1000 / 60);

// Initializing the canvas
// I am using native JS here, but you can use jQuery, 
// Mootools or anything you want
var canvas = document.getElementById("canvas");

// Initialize the context of the canvas
var ctx = canvas.getContext("2d");

// Set the canvas width and height to occupy full window
var W = window.innerWidth, H = window.innerHeight;
canvas.width = W;
canvas.height = H;

// Some variables for later use
var particleCount = 100,
	particles = [],
	minDist = 70,

// Function to paint the canvas black
function paintCanvas() {
	// Set the fill color to black
	ctx.fillStyle = "rgba(0,0,0,1)";
	// This will create a rectangle of white color from the 
	// top left (0,0) to the bottom right corner (W,H)

// Now the idea is to create some particles that will attract
// each other when they come close. We will set a minimum
// distance for it and also draw a line when they come
// close to each other.

// The attraction can be done by increasing their velocity as 
// they reach closer to each other

// Let's make a function that will act as a class for
// our particles.

function Particle() {
	// Position them randomly on the canvas
	// Math.random() generates a random value between 0
	// and 1 so we will need to multiply that with the
	// canvas width and height.
	this.x = Math.random() * W;
	this.y = Math.random() * H;
	// We would also need some velocity for the particles
	// so that they can move freely across the space
	this.vx = -1 + Math.random() * 2;
	this.vy = -1 + Math.random() * 2;

	// Now the radius of the particles. I want all of 
	// them to be equal in size so no Math.random() here..
	this.radius = 4;
	// This is the method that will draw the Particle on the
	// canvas. It is using the basic fillStyle, then we start
	// the path and after we use the `arc` function to 
	// draw our circle. The `arc` function accepts four
	// parameters in which first two depicts the position
	// of the center point of our arc as x and y coordinates.
	// The third value is for radius, then start angle, 
	// end angle and finally a boolean value which decides
	// whether the arc is to be drawn in counter clockwise or 
	// in a clockwise direction. False for clockwise.
	this.draw = function() {
		ctx.fillStyle = "white";
		ctx.arc(this.x, this.y, this.radius, 0, Math.PI * 2, false);
		// Fill the color to the arc that we just created

// Time to push the particles into an array
for(var i = 0; i < particleCount; i++) {
	particles.push(new Particle());

// Function to draw everything on the canvas that we'll use when 
// animating the whole scene.
function draw() {
	// Call the paintCanvas function here so that our canvas
	// will get re-painted in each next frame
	// Call the function that will draw the balls using a loop
	for (var i = 0; i < particles.length; i++) {
		p = particles[i];
	//Finally call the update function

// Give every particle some life
function update() {
	// In this function, we are first going to update every
	// particle's position according to their velocities
	for (var i = 0; i < particles.length; i++) {
		p = particles[i];
		// Change the velocities
		p.x += p.vx;
		p.y += p.vy
		// We don't want to make the particles leave the
		// area, so just change their position when they
		// touch the walls of the window
		if(p.x + p.radius > W) 
			p.x = p.radius;
		else if(p.x - p.radius < 0) {
			p.x = W - p.radius;
		if(p.y + p.radius > H) 
			p.y = p.radius;
		else if(p.y - p.radius < 0) {
			p.y = H - p.radius;
		// Now we need to make them attract each other
		// so first, we'll check the distance between
		// them and compare it to the minDist we have
		// already set
		// We will need another loop so that each
		// particle can be compared to every other particle
		// except itself
		for(var j = i + 1; j < particles.length; j++) {
			p2 = particles[j];
			distance(p, p2);

// Distance calculator between two particles
function distance(p1, p2) {
	var dist, colorIndex;
		dx = p1.x - p2.x;
		dy = p1.y - p2.y;
	dist = Math.sqrt(dx*dx + dy*dy);
	// Draw the line when distance is smaller
	// then the minimum distance
	if(dist <= minDist) {
		// Draw the line
    colorIndex = parseInt((100.0 * dist/minDist))+25;
		ctx.strokeStyle = "hsla(2," + colorIndex + "%,50%,"+ (1.2-dist/minDist) +")";
		ctx.moveTo(p.x, p.y);
		ctx.lineTo(p2.x, p2.y);
		// Some acceleration for the partcles 
		// depending upon their distance
		var ax = dx/2000,
			ay = dy/2000;
		// Apply the acceleration on the particles
		p1.vx -= ax;
		p1.vy -= ay;
		p2.vx += ax;
		p2.vy += ay;

// Start the main animation loop using requestAnimFrame
function animloop() {

🕑 One or more of the npm packages you are using needs to be built. You're the first person to ever need it! We're building it right now and your preview will start updating again when it's ready.