下面是整體代碼，按鍵Ctrl+C複製，複製完粘貼到記事本里面，把.txt後綴改成.html然後打開就可以看到這個炫酷的特效了。
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>編程特趣</title>
<style>
html,body {
margin:0;
padding:0;
overflow:hidden;
background-color:#000000
}
body {
height:100vh;
display:flex;
align-items:center;
justify-content:center;
}
.canvas {
display:block;
border-radius:50%;
}
.canvas-pattern {
display:none;
}
</style>
</head>
<body>
<canvas class="canvas canvas-pattern js-canvas" width="500" height="500"></canvas>
<canvas class="canvas js-duplicate" width="500" height="500"></canvas>
<script type="text/javascript">
const canvas = document.querySelector('.js-canvas');
const ctx = canvas.getContext('2d');
const canvas2 = document.querySelector('.js-duplicate');
const ctx2 = canvas2.getContext('2d');
const dim = Math.min(window.innerWidth, window.innerHeight) * 0.95;
const w = dim;
const h = dim;
const midX = w >> 1;
const midY = h >> 1;
const PI = Math.PI;
const TO_RADIAN = PI / 180;
const maxDepth = 5;
const maxSpread = 90 * TO_RADIAN;
let autoAnimate = true;
let divergeAt = 0.5;
let spread = 45 * TO_RADIAN;
let tick = 0;
let autoSpeed = 0.004;
let autoTick = 0;
canvas.width = canvas2.width = w;
canvas.height = canvas2.height = h;
class Branch {
constructor(position = {x : 0, y: 0}, length = 100, divergeAt = 0.5, angle = 0, depth = 0, spread = 45 * TO_RADIAN) {
this.position = position;
this.length = length;
this.divergeAt = divergeAt;
this.angle = angle;
this.depth = depth;
this.color = '#000';
this.spread = spread;
this.branches = [];
this.grow();
}
grow() {
if (!this.canBranch) {
return;
}
this.branches = [];
const nextLength = this.length * 0.75;
const nextDepth = this.depth + 1;
this.branches.push(
new Branch(
this.growPosition,
nextLength,
this.divergeAt,
this.angle + this.spread,
nextDepth,
this.spread
),
new Branch(
this.growPosition,
nextLength,
this.divergeAt,
this.angle - this.spread,
nextDepth,
this.spread
)
);
}
update(spread, divergeAt) {
this.spread = spread;
this.divergeAt = divergeAt;
this.grow();
}
get growPosition() {
const dl = this.length * this.divergeAt;
return {
x: this.position.x + (Math.cos(this.angle) * dl),
y: this.position.y + (Math.sin(this.angle) * dl),
};
}
get canBranch() {
return this.depth < maxDepth;
}
}
const rootBranch = new Branch(
{ x: midX, y: midY },
midY * 0.5,
divergeAt,
-90 * TO_RADIAN,
0,
spread
);
const drawBranch = (branch, phase) => {
const h = ~~(200 + (160 * phase));
const l = 50 + ~~(((branch.depth / (maxDepth + 1))) * 50);
const endX = branch.length;
const endY = 0;
const r = 2;
ctx.save();
ctx.strokeStyle = `hsl(${h}, 100%, ${l}%)`;
ctx.translate(branch.position.x, branch.position.y);
ctx.rotate(branch.angle);
ctx.beginPath();
ctx.moveTo(0, 0);
ctx.lineTo(endX, endY);
ctx.stroke();
ctx.closePath();
ctx.beginPath();
ctx.fillStyle = `hsl(${h}, 100%, 50%)`;
ctx.arc(endX, endY, r, 0, PI * 2, false);
ctx.fill();
ctx.closePath();
ctx.restore();
branch.branches.forEach((b) => {
drawBranch(b, phase);
});
};
const map = (value, start1, stop1, start2, stop2) => ((value - start1) / (stop1 - start1)) * (stop2 - start2) + start2;
const clear = () => {
ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
ctx2.clearRect(0, 0, ctx2.canvas.width, ctx2.canvas.height);
};
const loop = () => {
let phase = rootBranch.spread / maxSpread;
clear(phase);
if (autoAnimate) {
phase = map(Math.sin(autoTick), -1, 1, 0, 1);
spread = phase * maxSpread;
divergeAt = map(Math.sin(autoTick), -1, 1, 0, 0.5);
autoTick += autoSpeed;
}
rootBranch.update(spread, divergeAt);
drawBranch(rootBranch, phase);
const numSegments = 12;
const angleInc = PI * 2 / numSegments;
let angle = tick;
for (let i = 0; i < numSegments; i++) {
ctx2.save();
ctx2.translate(midX, midY);
ctx2.rotate(angle);
ctx2.drawImage(canvas, -w / 2, -h / 2);
ctx2.restore();
angle += angleInc;
}
tick += 0.002;
requestAnimationFrame(loop);
};
const onPointerMove = (e) => {
if (autoAnimate) {
return;
}
const target = (e.touches && e.touches.length) ? e.touches[0] : e;
const { clientX: x, clientY: y } = target;
const width = window.innerWidth;
const height = window.innerHeight;
spread = (x / width) * maxSpread;
divergeAt = y / height;
};
document.body.addEventListener('mousemove', onPointerMove);
document.body.addEventListener('touchmove', onPointerMove);
document.addEventListener('mouseenter', () => {
autoAnimate = false;
});
document.addEventListener('mouseleave', () => {
autoAnimate = true;
});
loop();
</script>
</body>
</html>
一起來看效果！！！
