A Pen By
dissimulate
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

` ````
<canvas></canvas>
```

` ````
body {
margin: 0;
}
```

` ````
const MAX_AGE = 80;
const LEAF_DISTANCE = 6;
const DIAMETER = 10;
const LEAFE_SIZE = 3;
const TREE_VARIANCE = 2;
const BRANCH_VARIANCE = 30;
const DRAW_DISTANCE = 3;
const canvas = document.querySelector('canvas');
const ctx = canvas.getContext('2d', { alpha: false });
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
/* ~~~~~ */
class PerlinNoise {
static grad3 = [
[1, 1, 0], [-1, 1, 0], [1, -1, 0], [-1, -1, 0],
[1, 0, 1], [-1, 0, 1], [1, 0, -1], [-1, 0, -1],
[0, 1, 1], [0, -1, 1], [0, 1, -1], [0, -1, -1],
];
constructor () {
this.p = [];
for (let i = 0; i < 256; i++) {
this.p[i] = ~~(Math.random() * 256);
}
this.perm = [];
for (let i = 0; i < 512; i++) {
this.perm[i] = this.p[i & 255];
}
}
static dot (g, x, y, z) {
return g[0] * x + g[1] * y + g[2] * z;
}
static mix (a, b, t) {
return (1.0 - t) * a + t * b;
}
static fade (t) {
return t * t * t * (t * (t * 6.0 - 15.0) + 10.0);
}
at (x = 0, y = 0, z = 0) {
let X = ~~x;
let Y = ~~y;
let Z = ~~z;
x = x - X;
y = y - Y;
z = z - Z;
X = X & 255;
Y = Y & 255;
Z = Z & 255;
const gi000 = this.perm[X + this.perm[Y + this.perm[Z]]] % 12;
const gi001 = this.perm[X + this.perm[Y + this.perm[Z + 1]]] % 12;
const gi010 = this.perm[X + this.perm[Y + 1 + this.perm[Z]]] % 12;
const gi011 = this.perm[X + this.perm[Y + 1 + this.perm[Z + 1]]] % 12;
const gi100 = this.perm[X + 1 + this.perm[Y + this.perm[Z]]] % 12;
const gi101 = this.perm[X + 1 + this.perm[Y + this.perm[Z + 1]]] % 12;
const gi110 = this.perm[X + 1 + this.perm[Y + 1 + this.perm[Z]]] % 12;
const gi111 = this.perm[X + 1 + this.perm[Y + 1 + this.perm[Z + 1]]] % 12;
const n000 = PerlinNoise.dot(PerlinNoise.grad3[gi000], x, y, z);
const n100 = PerlinNoise.dot(PerlinNoise.grad3[gi100], x - 1, y, z);
const n010 = PerlinNoise.dot(PerlinNoise.grad3[gi010], x, y - 1, z);
const n110 = PerlinNoise.dot(PerlinNoise.grad3[gi110], x - 1, y - 1, z);
const n001 = PerlinNoise.dot(PerlinNoise.grad3[gi001], x, y, z - 1);
const n101 = PerlinNoise.dot(PerlinNoise.grad3[gi101], x - 1, y, z - 1);
const n011 = PerlinNoise.dot(PerlinNoise.grad3[gi011], x, y - 1, z - 1);
const n111 = PerlinNoise.dot(PerlinNoise.grad3[gi111], x - 1, y - 1, z - 1);
const u = PerlinNoise.fade(x);
const v = PerlinNoise.fade(y);
const w = PerlinNoise.fade(z);
const nx00 = PerlinNoise.mix(n000, n100, u);
const nx01 = PerlinNoise.mix(n001, n101, u);
const nx10 = PerlinNoise.mix(n010, n110, u);
const nx11 = PerlinNoise.mix(n011, n111, u);
const nxy0 = PerlinNoise.mix(nx00, nx10, v);
const nxy1 = PerlinNoise.mix(nx01, nx11, v);
const nxyz = PerlinNoise.mix(nxy0, nxy1, w);
return nxyz;
}
}
/* ~~~~~ */
const radians = (degrees) => degrees * Math.PI / 180;
const noise = new PerlinNoise();
const trees = [];
class Point {
constructor (x, y, colour, age = 0, degrees = 0, variance = 0) {
this.x = x;
this.y = y;
this.opacity = (MAX_AGE - age) / MAX_AGE;
this.colour = colour;
this.radius = DIAMETER;
this.age = age;
this.degrees = degrees;
this.variance = variance;
}
}
const addLeaf = (tree, point) => {
const leaf = new Point(
point.x + (-LEAF_DISTANCE + Math.random() * (LEAF_DISTANCE * 2)),
point.y + (-LEAF_DISTANCE + Math.random() * (LEAF_DISTANCE * 2)),
[point.colour[0] + 25, point.colour[1], point.colour[2]],
);
leaf.opacity = 0;
leaf.spawned = true;
leaf.radius = LEAFE_SIZE + Math.random() * (LEAFE_SIZE * 2);
tree.leaves.push(leaf);
};
class Tree {
constructor (x = 0, y = 0, colour) {
this.x = x;
this.y = y;
this.points = [
new Point(x, y, colour, 0, -90, TREE_VARIANCE),
];
this.leaves = [];
}
}
const update = (tree) => {
if (tree.done) return;
let done = true;
tree.points.forEach((point) => {
if (point.spawned || point.age >= MAX_AGE) {
return;
}
done = false;
++point.age;
const branch = (variance) => {
const reduce = 0.01;
const n = (noise.at((point.x + point.age) * reduce, (point.y + point.age) * reduce) - 0.5) * 4 * Math.PI;
const mag = noise.at((point.y + point.age) * reduce, (point.x + point.age) * reduce);
const dirX = Math.cos(n) * mag;
const dirY = Math.sin(n) * mag;
const diff = variance * point.opacity;
const degrees = point.degrees + (-diff + Math.random() * diff * 2);
const randX = Math.cos(radians(degrees)) * DRAW_DISTANCE;
const randY = Math.sin(radians(degrees)) * DRAW_DISTANCE;
const x = point.x + dirX + randX;
const y = point.y + dirY + randY;
tree.points.push(new Point(
x,
y,
point.colour,
point.age,
degrees,
variance,
));
};
if (point.age > MAX_AGE * 0.2 &&
point.age < MAX_AGE * 0.8 &&
Math.random() < 0.07 * (1 - point.opacity * 0.4)) {
branch(point.variance + BRANCH_VARIANCE);
}
if (Math.random() < 0.2 && point.age > MAX_AGE * 0.8) {
addLeaf(tree, point);
addLeaf(tree, point);
addLeaf(tree, point);
}
branch(point.variance);
point.spawned = true;
});
tree.done = done;
};
const addTree = (x, y) => {
ctx.fillStyle = 'rgba(255, 255, 255, 0.1)';
ctx.fillRect(0, 0, canvas.width, canvas.height);
const colour = [
Math.random() * 360,
80,
80
];
trees.push(new Tree(x, y, colour));
};
const drawPoint = (point, radius, opacity = 1) => {
ctx.beginPath();
ctx.arc(point.x, point.y, radius || (point.radius * point.opacity), 0, Math.PI * 2);
ctx.fillStyle = `hsla(${point.colour[0]}, ${point.colour[1]}%, ${point.colour[2] + 20 * point.opacity}%, ${opacity})`;
ctx.fill();
};
const draw = (tree) => {
let done = true;
tree.points.forEach((point) => {
if (point.drawn) return;
done = false;
drawPoint(point);
point.drawn = true;
});
done && tree.leaves.forEach((point) => {
if (point.drawn) return;
done = false;
drawPoint(point, point.radius, 0.15);
point.drawn = true;
});
done && trees.splice(trees.indexOf(tree), 1);
};
const loop = () => {
trees.forEach(update);
trees.forEach(draw);
window.requestAnimationFrame(loop);
};
ctx.fillStyle = '#fff';
ctx.fillRect(0, 0, canvas.width, canvas.height);
ctx.font = 'normal normal 100 30px Helvetica';
ctx.textAlign = 'center';
ctx.textSize = 20;
ctx.fillStyle = 'rgba(0, 0, 0, 0.1)';
ctx.fillText('Click to plant some trees.', canvas.width / 2, canvas.height / 2);
loop();
canvas.onmousedown = (e) => {
addTree(e.offsetX, e.offsetY, 1);
};
addTree(canvas.width * 0.1, canvas.height * 0.8, 1);
addTree(canvas.width * 0.9, canvas.height * 0.8, 1);
```

999px

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

Alt F
Opt F
Find & Replace

Also see: Tab Triggers