A Pen By
Matei Copot
Pro

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.

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+ add another resource

` ````
<canvas id=c></canvas>
```

` ````
canvas {
position: absolute;
top: 0;
left: 0;
}
```

` ````
let w = c.width = window.innerWidth;
let h = c.height = window.innerHeight;
const ctx = c.getContext('2d');
const opts = {
hexLength: 30,
lenFn: ({ len, t }) =>
len + Math.sin(t),
radFn: ({ rad, len, t, excitement }) =>
rad + (excitement + opts.propFn({ len, t }))*2 / 4,
propFn: ({ len, t }) =>
len / opts.hexLength / 10 - t,
excitementFn: ({ len, t }) =>
Math.sin(opts.propFn({ len, t }))**2,
colorFn: ({ rad, excitement, t }) =>
`hsl(${rad / Math.TAU * 360 + t}, ${excitement * 100}%, ${20 + excitement * 50}%)`,
timeStep: .01,
randomJig: 8,
repaintColor: 'rgba(0,0,0,.1)'
};
let tick = 0;
Math.TAU = 6.28318530717958647692;
const vertices = [];
class Vertex {
constructor({ x, y }) {
this.len = Math.sqrt(x*x + y*y);
this.rad = Math.acos(x / this.len) * (y > 0 ? 1 : -1) + .13;
this.prevPoint = { x, y };
}
step() {
const excitement = opts.excitementFn({ len: this.len, t: tick });
const param = {
len: this.len,
rad: this.rad,
t: tick,
excitement
};
const nextLen = opts.lenFn(param);
const nextRad = opts.radFn(param);
const color = opts.colorFn(param);
ctx.strokeStyle = color;
ctx.lineWidth = excitement + .2;
ctx.beginPath();
ctx.moveTo(this.prevPoint.x, this.prevPoint.y);
this.prevPoint.x = nextLen * Math.cos(nextRad) +
Math.random() * (1-excitement)**2 * opts.randomJig * 2 - opts.randomJig;
this.prevPoint.y = nextLen * Math.sin(nextRad) +
Math.random() * (1-excitement)**2 * opts.randomJig * 2 - opts.randomJig;
ctx.lineTo(this.prevPoint.x, this.prevPoint.y);
ctx.stroke();
}
static gen() {
vertices.length = 0;
const hexCos = Math.cos(Math.TAU / 12) * opts.hexLength;
const hexSin = Math.sin(Math.TAU / 12) * opts.hexLength;
let alternanceX = false;
for(let x = 0; x < w; x += hexCos) {
let alternance = alternanceX = !alternanceX;
for(let y = 0; y < h; y += hexSin + opts.hexLength) {
alternance = !alternance;
vertices.push(new Vertex({
x: x - w / 2,
y: y + alternance * hexSin - h / 2
}))
}
}
}
}
Vertex.gen();
ctx.fillStyle = '#222';
ctx.fillRect(0, 0, w, h);
const anim = () => {
window.requestAnimationFrame(anim);
tick += opts.timeStep;
ctx.fillStyle = opts.repaintColor;
ctx.fillRect(0, 0, w, h);
ctx.translate(w/2, h/2);
vertices.forEach((vertex) => vertex.step());
ctx.translate(-w/2, -h/2);
}
anim();
window.addEventListener('resize', () => {
w = c.width = window.innerWidth;
h = c.height = window.innerHeight;
Vertex.gen();
tick = 0;
ctx.fillStyle = '#222';
ctx.fillRect(0, 0, w, h);
})
```

999px

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