HTML5 CSS3银河系星空闪耀网页背景动画特效

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。

【源代码展示】

<!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[count] = 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[i].draw();
  };
  window.requestAnimationFrame(animation);
}
animation();
</script>
</body>
</html>

----------------------------------------------------------------------------------------------------------------------------------------------感谢观看!期待您的下次光临!

原文地址:https://www.cnblogs.com/varchar-pig/p/14224566.html