HTML5 CSS3银河系星空闪耀网页背景动画特效

蓝星世界 發表於 2021-1-3 00:26:00

HTML5 CSS3银河系星空闪耀网页背景动画特效

<h2>HTML5 CSS3银河系星空闪耀网页背景动画特效，运行本效果后，一幅像银河系的星空图展现眼前，远处星空闪耀，星空整体上同样也具有动画效果，可很好的应用于网页背景中，本背景动画的生成依赖Canvas技术，运行时请选择支持Canvas技术的浏览器，IE就免谈了，推荐Chrome。提示：若不能运行，请将代码保存到本地HTML文件中，然后使用Chrome打开。</h2>
<img src="https://img2020.cnblogs.com/blog/2176794/202101/2176794-20210103002509163-1527367996.gif" alt="" loading="lazy">
 
【源代码展示】
<div class="cnblogs_code">
<pre><!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>HTML5 Canvas全屏背景动画</title>
<style>
body {
background: #060e1b;
overflow: hidden;
}
.codrops-demos {
font-size: 0.8em;
text-align:center;
position:absolute;
z-index:99;
width:96%;
}
.codrops-demos a {
display: inline-block;
margin: 0.35em 0.1em;
padding: 0.5em 1.2em;
outline: none;
text-decoration: none;
text-transform: uppercase;
letter-spacing: 1px;
font-weight: 700;
border-radius: 2px;
font-size: 110%;
border: 2px solid transparent;
color:#fff;
}
.codrops-demos a:hover,
.codrops-demos a.current-demo {
border-color: #383a3c;
}
</style>
</head>
<body>
<canvas id="canvas"></canvas>
<script>
"use strict";
var canvas = document.getElementById('canvas'),
ctx = canvas.getContext('2d'),
w = canvas.width = window.innerWidth,
h = canvas.height = window.innerHeight,
hue = 217,
stars = [],
count = 0,
maxStars = 1400;
var canvas2 = document.createElement('canvas'),
ctx2 = canvas2.getContext('2d');
canvas2.width = 100;
canvas2.height = 100;
var half = canvas2.width/2,
 gradient2 = ctx2.createRadialGradient(half, half, 0, half, half, half);
gradient2.addColorStop(0.025, '#fff');
gradient2.addColorStop(0.1, 'hsl(' + hue + ', 61%, 33%)');
gradient2.addColorStop(0.25, 'hsl(' + hue + ', 64%, 6%)');
gradient2.addColorStop(1, 'transparent');
ctx2.fillStyle = gradient2;
ctx2.beginPath();
ctx2.arc(half, half, half, 0, Math.PI * 2);
ctx2.fill();
// End cache
function random(min, max) {
if (arguments.length < 2) {
max = min;
min = 0;
}
if (min > max) {
var hold = max;
max = min;
min = hold;
}
return Math.floor(Math.random() * (max - min + 1)) + min;
}
var Star = function() {
this.orbitRadius = random(w / 2 - 50);
this.radius = random(100, this.orbitRadius) / 10;
this.orbitX = w / 2;
this.orbitY = h / 2;
this.timePassed = random(0, maxStars);
this.speed = random(this.orbitRadius) / 900000;
this.alpha = random(2, 10) / 10;
count++;
stars = this;
}
Star.prototype.draw = function() {
var x = Math.sin(this.timePassed + 1) * this.orbitRadius + this.orbitX,
y = Math.cos(this.timePassed) * this.orbitRadius/2 + this.orbitY,
 twinkle = random(10);
if (twinkle === 1 && this.alpha > 0) {
this.alpha -= 0.05;
} else if (twinkle === 2 && this.alpha < 1) {
this.alpha += 0.05;
}
ctx.globalAlpha = this.alpha;
ctx.drawImage(canvas2, x - this.radius / 2, y - this.radius / 2, this.radius, this.radius);
this.timePassed += this.speed;
}
for (var i = 0; i < maxStars; i++) {
new Star();
}
function animation() {
ctx.globalCompositeOperation = 'source-over';
ctx.globalAlpha = 0.8;
ctx.fillStyle = 'hsla(' + hue + ', 64%, 6%, 1)';
ctx.fillRect(0, 0, w, h)
ctx.globalCompositeOperation = 'lighter';
for (var i = 1, l = stars.length; i < l; i++) {
stars.draw();
};
window.requestAnimationFrame(animation);
}
animation();
</script>
</body>
</html></pre>
</div>
 
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来源：https://www.cnblogs.com/varchar-pig/p/14224566.html

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HTML5 CSS3银河系星空闪耀网页背景动画特效