A Pen By
Gerard Ferrandez
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.

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.

You can apply a script from anywhere on the web to your Pen. Just put a URL to it here and we'll add it, in the order you have them, before the JavaScript in the Pen itself.

If the script you link to has the file extension of a preprocessor, we'll attempt to process it before applying.

You can also link to another Pen here, and we'll pull the JavaScript from that Pen and include it. If it's using a matching preprocessor, we'll combine the code before preprocessing, so you can use the linked Pen as a true dependency.

+ add another resource

` ````
<div id="screen"></div>
```

` ````
html, body {
overflow: hidden;
touch-action: none;
content-zooming: none;
position: absolute;
margin: 0;
padding: 0;
width: 100%;
height: 100%;
background: #000;
}
#screen {
position: absolute;
width: 100vh;
height: 100vh;
max-height: 100vw;
max-width: 100vw;
margin: auto;
top: 0;
bottom: 0;
left: 0;
right: 0;
user-select: none;
}
#screen canvas {
position: relative;
float: left;
display: block;
width: 28.7vmin;
height: 28.7vmin;
background:#222;
margin-left: 3vmin;
margin-top: 3vmin;
border-radius: 3vmin;
}
```

` ````
"use strict";
{
const Box = class {
constructor(container, i) {
this.canvas = document.createElement("canvas");
container.appendChild(this.canvas);
this.width = this.canvas.width = this.canvas.offsetWidth;
this.height = this.canvas.height = this.canvas.offsetHeight;
this.ctx = this.canvas.getContext("2d");
this.ctx.lineCap = "round";
this.points = Array.from(
{ length: 12 },
_ => new Box.Point(this.width * 0.5, this.width * 0.5)
);
this.constraints = [];
this.color = `hsl(${10 * i}, 70%, 30%)`;
// links p1, p2, length, width
const links = [
[0, 1, 6, 5],
[1, 2, 5, 4],
[3, 7, 10, 6],
[7, 8, 7, 4],
[3, 9, 10, 6],
[9, 10, 7, 4],
[0, 4, 5, 0],
[0, 3, 7, 9],
[0, 5, 6, 5],
[5, 6, 5, 4],
[4, 11, 0.1, 11]
];
// constaints: p1, p2, p3, angle, range
const p2 = Math.PI / 2;
const p3 = Math.PI / 3;
[
[0, 4, 11, 0, 0, 0],
[4, 0, 3, 0, 1, 0.05],
[3, 0, 4, 0, 1, 0.05],
[3, 0, 1, p2, p2 * 4, 0],
[0, 1, 2, -p2, p3, 0.05],
[3, 0, 5, p2, p2 * 4, 0],
[0, 5, 6, -p2, p3, 0.05],
[0, 3, 7, -p3 + 0.5, p2, 0.05],
[0, 3, 9, -p3 + 0.5, p2, 0.05],
[3, 7, 8, p2, p3, 0.05],
[3, 9, 10, p2, p3, 0.05]
].forEach(p => {
this.constraints.push(new Box.Constraint(this, links, p, this.width / 30));
});
}
run() {
this.ctx.setTransform(0, 1, 1, 0, 0, 0);
this.ctx.clearRect(0, 0, this.width + 1, this.height + 1);
this.ctx.globalCompositeOperation = "lighter";
for (const constraint of this.constraints) constraint.solve();
for (const point of this.points) point.integrate();
}
};
Box.Point = class {
constructor(x, y) {
this.x = x;
this.y = y;
this.xb = x;
this.yb = y
this.w = 0;
}
integrate() {
const vx = (this.x - this.xb) * 0.995;
const vy = (this.y - this.yb) * 0.995;
this.xb = this.x;
this.yb = this.y;
this.x += vx;
this.y += vy;
}
};
Box.Constraint = class {
constructor(box, links, p, s) {
this.ctx = box.ctx;
this.p1 = box.points[p[0]];
this.p2 = box.points[p[1]];
this.p3 = box.points[p[2]];
this.m = 0;
this.angle = p[3];
this.range = p[4];
this.force = p[5];
const link1 = this.link(links, p[0], p[1]);
const link2 = this.link(links, p[1], p[2]);
this.len1 = link1[2] * s;
this.len2 = link2[2] * s;
this.width = link2[3] * s * 0.5;
if (this.width * 0.5 > this.p3.w) this.p3.w = this.width * 0.5;
this.shape = document.createElement("canvas");
if (this.width) {
this.shape.width = this.len2 + this.width;
this.shape.height = this.width;
const ict = this.shape.getContext("2d");
ict.lineCap = "round";
ict.strokeStyle = box.color;
ict.beginPath();
ict.lineWidth = this.width * 0.9;
ict.moveTo(this.width * 0.5, this.width * 0.5);
ict.lineTo(this.len2 + this.width * 0.5, this.width * 0.5);
ict.stroke();
}
}
link(links, p0, p1) {
for (const link of links) {
if (
(p0 === link[0] && p1 === link[1]) ||
(p1 === link[0] && p0 === link[1])
)
return link;
}
}
solve() {
const a1 = Math.atan2(this.p2.y - this.p1.y, this.p2.x - this.p1.x);
const b1 = Math.atan2(this.p3.y - this.p2.y, this.p3.x - this.p2.x);
const c = this.angle - (b1 - a1);
const d = c > Math.PI ? c - 2 * Math.PI : c < -Math.PI ? c + 2 * Math.PI : c;
const e = Math.abs(d) > this.range ? (-Math.sign(d) * this.range + d) * this.force : 0;
const cos1 = Math.cos(a1 - e);
const sin1 = Math.sin(a1 - e);
const x1 = this.p1.x + (this.p2.x - this.p1.x) * 0.5;
const y1 = this.p1.y + (this.p2.y - this.p1.y) * 0.5;
this.p1.x = x1 - cos1 * this.len1 * 0.5;
this.p1.y = y1 - sin1 * this.len1 * 0.5;
this.p2.x = x1 + cos1 * this.len1 * 0.5;
this.p2.y = y1 + sin1 * this.len1 * 0.5;
this.m += 0.0005 * (Math.random() - 0.5);
this.m *= 0.99;
const a2 = this.m + Math.atan2(this.p2.y - this.p3.y, this.p2.x - this.p3.x) + e;
const cos2 = Math.cos(a2);
const sin2 = Math.sin(a2);
const x2 = this.p3.x + (this.p2.x - this.p3.x) * 0.5;
const y2 = this.p3.y + (this.p2.y - this.p3.y) * 0.5;
this.p3.x = x2 - cos2 * this.len2 * 0.5;
this.p3.y = y2 - sin2 * this.len2 * 0.5;
this.p2.x = x2 + cos2 * this.len2 * 0.5;
this.p2.y = y2 + sin2 * this.len2 * 0.5;
if (this.width) {
this.ctx.setTransform(cos2, sin2, -sin2, cos2, this.p2.x, this.p2.y);
this.ctx.drawImage(
this.shape,
-this.len2 - this.width * 0.5,
-this.width * 0.5
);
}
}
};
const screen = document.querySelector("#screen");
const boxes = Array.from({ length: 9 }, (v, i) => new Box(screen, i));
const run = () => {
requestAnimationFrame(run);
for (const box of boxes) box.run();
};
run();
}
```

999px

Loading
..................

Alt F
Opt F
Find & Replace

Also see: Tab Triggers