JavaScript preprocessors can help make authoring JavaScript easier and more convenient. For instance, CoffeeScript can help prevent easy-to-make mistakes and offer a cleaner syntax and Babel can bring ECMAScript 6 features to browsers that only support ECMAScript 5.

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.

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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.

` ````
* {
margin: 0;
border: none;
}
html,
body {
height: 100%;
width: 100%;
overflow: hidden;
}
body {
background: black;
position: relative;
}
canvas {
position: absolute;
top: 0;
left: 0;
}
canvas.flash {
filter: blur(1px) contrast(3);
}
```

` ````
/**
* Had fun with particles again, this time for the #CodePenChallenge!
*
* @author Alexandre Andrieux <alex@icosacid.com>
* @since 2018-03-05
*/
var Stargate = {};
Stargate.init = function() {
// Create canvas node
var flashCanvas = document.createElement('canvas'),
permanentCanvas = document.createElement('canvas');
flashCanvas.className += 'flash';
permanentCanvas.className = 'permanent';
flashCanvas.width = permanentCanvas.width = window.innerWidth;
flashCanvas.height = permanentCanvas.height = window.innerHeight;
this.fCtx = flashCanvas.getContext('2d');
this.pCtx = permanentCanvas.getContext('2d');
this.width = flashCanvas.width;
this.height = flashCanvas.height;
this.baseDim = Math.min(this.width, this.height);
// Append canvas to body
document.getElementsByTagName('body')[0].appendChild(permanentCanvas);
document.getElementsByTagName('body')[0].appendChild(flashCanvas);
// Set global composite operation
this.fCtx.globalCompositeOperation = 'lighter';
this.xC = this.width / 2;
this.yC = this.height / 2;
this.r = 0.8 * this.baseDim / 2;
this.particles = [];
this.population = 20;
this.stepCount = 0;
// Give birth
for (var i = 0; i < this.population; i++) {
Stargate.birth(i);
}
};
Stargate.birth = function(i) {
var r = this.r,
angle = i/4 * 2 * Math.PI,
x = this.xC + r * Math.cos(angle),
y = this.yC + r * Math.sin(angle),
speed = 0.1 * (-0.5 + Math.random());
var particle = {
x: x,
y: y,
r: r,
size: 30,
angle: angle,
speed: speed
};
this.particles.push(particle);
};
Stargate.evolve = function() {
this.stepCount++;
this.move();
this.draw();
};
Stargate.move = function() {
for (var i = 0; i < this.particles.length; i++) {
var p = this.particles[i];
p.angle += p.speed;
p.x = this.xC + p.r * Math.cos(p.angle);
p.y = this.yC + p.r * Math.sin(p.angle);
}
};
Stargate.draw = function() {
// Clear canvases
this.pCtx.clearRect(0, 0, this.width, this.height);
this.fCtx.clearRect(0, 0, this.width, this.height);
// Draw background circles
for (var k = 0; k < this.baseDim * 0.8; k += 15) {
var rad = 0.002 * k * k * (1.5 + 0.5 * Math.sin(this.stepCount / 50)) * (1 + Math.cos(k / 20));
this.pCtx.beginPath();
this.pCtx.arc(this.xC, this.yC, rad, 0, 2 * Math.PI, true);
this.pCtx.lineWidth = 300 / Math.max(8, rad);
var hue = 180 + rad / 4,
color = 'hsla(' + hue + ', 83%, 43%, 1)';
this.pCtx.strokeStyle = color;
this.pCtx.shadowBlur = 10;
this.pCtx.shadowColor = color;
this.pCtx.stroke();
this.pCtx.closePath();
}
// Draw particles
for (var i = 0; i < this.particles.length; i++) {
var p = this.particles[i];
// Draw line between me and my right neighbour on the list
if (i < this.particles.length - 1) {
var randomIndex = Math.floor((this.particles.length) * Math.random());
//var nextParticle = this.particles[randomIndex];
var nextParticle = this.particles[i + 1];
this.fCtx.moveTo(p.x, p.y);
this.fCtx.lineTo(nextParticle.x, nextParticle.y);
// Add circle somewhere on the way
var prop = 0.5;//Math.random(),
x = prop * p.x + (1 - prop) * nextParticle.x,
y = prop * p.y + (1 - prop) * nextParticle.y;
this.fCtx.arc(x, y, 10, 0, 2 * Math.PI, true);
this.fCtx.lineWidth = 0.5;
this.fCtx.strokeStyle = 'white';
this.fCtx.stroke();
this.fCtx.closePath();
}
// Draw triangles around the particle position
this.fCtx.beginPath();
for (var j = 0; j < 5; j++) {
var angle = j * 2/3 * Math.PI + p.angle + Math.PI / 3;
var x = p.x + p.size * Math.cos(angle),
y = p.y + p.size * Math.sin(angle);
if (j == 0) this.fCtx.moveTo(x, y);
else {
this.fCtx.lineTo(x, y);
}
}
//this.fCtx.arc(p.x, p.y, p.size, 0, 2 * Math.PI, true);
this.fCtx.fillStyle = 'rgba(0, 0, 0, 1)';
this.fCtx.strokeStyle = 'hsla(260, 83%, 52%, 1)';
this.fCtx.lineWidth = 6;
this.fCtx.fill();
this.fCtx.stroke();
this.fCtx.closePath();
}
}
document.addEventListener('DOMContentLoaded', function() {
Stargate.init();
Stargate.draw();
setInterval(function() {
Stargate.evolve();
}, 50);
});
```

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