search

Home  >  Article  >  Web Front-end  >  CSS and JS realize the beautiful starry sky trajectory movement effect

CSS and JS realize the beautiful starry sky trajectory movement effect

小云云
小云云Original
2018-01-31 11:16:492804browse

This article mainly shares with you a beautiful starry sky trajectory motion effect realized using CSS+JS. The effect is very realistic. The editor below brings you an example code. Friends who need it can refer to it. I hope it can help you.

Let me share with you the renderings first:

Let me share with you a beautiful starry sky trajectory motion effect achieved using CSS+JS. This effect is not inferior to Flash . The relevant codes are as follows: 


<!doctype html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>cloth</title>
  <style>
   body {
  background: #000; 
}
img {
  display: block;
 float: left; 
  margin: 0 1px 0 0;
}
canvas {
  background: #131c35 linear-gradient(#192853, #131c35);
 display: block;
  float: left;
  /* uncomment to test overlay */
  /*
  position: absolute;
  left: 0;
  opacity: .5;
  top: 0;
  */  
}
  </style>
</head>
<body>
  <p id="container"></p>
  <script type="text/javascript" src="http://cdn.gbtags.com/jquery/1.11.1/jquery.min.js"></script>
  <canvas id="c"></canvas>
  <img src="http://dribbble.s3.amazonaws.com/users/36991/screenshots/674715/game.png" />
  <script>
    var c = document.getElementById(&#39;c&#39;),
    ctx = c.getContext(&#39;2d&#39;),
    cw = c.width = 400,
  ch = c.height = 300,
    rand = function(a,b){return ~~((Math.random()*(b-a+1))+a);},
    dToR = function(degrees){
        return degrees * (Math.PI / 180);
    },
    circle = {
      x: (cw / 2) + 5,
      y: (ch / 2) + 22,
      radius: 90,
      speed: 2,
      rotation: 0,
      angleStart: 270,
      angleEnd: 90,
      hue: 220,
      thickness: 18,
      blur: 25
    },
    particles = [],
    particleMax = 100,
    updateCircle = function(){
      if(circle.rotation < 360){
       circle.rotation += circle.speed;
      } else {
       circle.rotation = 0; 
      }
    },
    renderCircle = function(){
      ctx.save();
      ctx.translate(circle.x, circle.y);
      ctx.rotate(dToR(circle.rotation));
      ctx.beginPath();
      ctx.arc(0, 0, circle.radius, dToR(circle.angleStart), dToR(circle.angleEnd), true);
      ctx.lineWidth = circle.thickness;    
      ctx.strokeStyle = gradient1;
      ctx.stroke();
      ctx.restore();
    },
    renderCircleBorder = function(){
      ctx.save();
      ctx.translate(circle.x, circle.y);
      ctx.rotate(dToR(circle.rotation));
      ctx.beginPath();
      ctx.arc(0, 0, circle.radius + (circle.thickness/2), dToR(circle.angleStart), dToR(circle.angleEnd), true);
      ctx.lineWidth = 2;  
      ctx.strokeStyle = gradient2;
      ctx.stroke();
      ctx.restore();
    },
  renderCircleFlare = function(){
      ctx.save();
      ctx.translate(circle.x, circle.y);
      ctx.rotate(dToR(circle.rotation+185));
      ctx.scale(1,1);
      ctx.beginPath();
      ctx.arc(0, circle.radius, 30, 0, Math.PI *2, false);
      ctx.closePath();
      var gradient3 = ctx.createRadialGradient(0, circle.radius, 0, 0, circle.radius, 30);      
      gradient3.addColorStop(0, &#39;hsla(330, 50%, 50%, .35)&#39;);
      gradient3.addColorStop(1, &#39;hsla(330, 50%, 50%, 0)&#39;);
      ctx.fillStyle = gradient3;
      ctx.fill();     
      ctx.restore();
    },
    renderCircleFlare2 = function(){
      ctx.save();
      ctx.translate(circle.x, circle.y);
      ctx.rotate(dToR(circle.rotation+165));
      ctx.scale(1.5,1);
      ctx.beginPath();
      ctx.arc(0, circle.radius, 25, 0, Math.PI *2, false);
      ctx.closePath();
      var gradient4 = ctx.createRadialGradient(0, circle.radius, 0, 0, circle.radius, 25);
      gradient4.addColorStop(0, &#39;hsla(30, 100%, 50%, .2)&#39;);
      gradient4.addColorStop(1, &#39;hsla(30, 100%, 50%, 0)&#39;);
      ctx.fillStyle = gradient4;
      ctx.fill();     
      ctx.restore();
    },
     createParticles = function(){
      if(particles.length < particleMax){
        particles.push({
          x: (circle.x + circle.radius * Math.cos(dToR(circle.rotation-85))) + (rand(0, circle.thickness*2) - circle.thickness),
          y: (circle.y + circle.radius * Math.sin(dToR(circle.rotation-85))) + (rand(0, circle.thickness*2) - circle.thickness),
          vx: (rand(0, 100)-50)/1000,
          vy: (rand(0, 100)-50)/1000,
          radius: rand(1, 6)/2,
          alpha: rand(10, 20)/100
        });
      }
    },
    updateParticles = function(){
      var i = particles.length;
      while(i--){
       var p = particles[i];
        p.vx += (rand(0, 100)-50)/750;
        p.vy += (rand(0, 100)-50)/750;
        p.x += p.vx;
        p.y += p.vy;
        p.alpha -= .01;
        if(p.alpha < .02){
          particles.splice(i, 1)
        }
      }
    },
    renderParticles = function(){
      var i = particles.length;
      while(i--){
       var p = particles[i];
        ctx.beginPath();
        ctx.fillRect(p.x, p.y, p.radius, p.radius);
        ctx.closePath();
        ctx.fillStyle = &#39;hsla(0, 0%, 100%, &#39;+p.alpha+&#39;)&#39;;
      }
    },
    clear = function(){
      ctx.globalCompositeOperation = &#39;destination-out&#39;;
      ctx.fillStyle = &#39;rgba(0, 0, 0, .1)&#39;;
      ctx.fillRect(0, 0, cw, ch);
      ctx.globalCompositeOperation = &#39;lighter&#39;;  
    }
    loop = function(){
      clear();
      updateCircle();
      renderCircle();
      renderCircleBorder();
      renderCircleFlare();
      renderCircleFlare2();
      createParticles();
      updateParticles();
      renderParticles();
    }
/* Append Canvas */
//document.body.appendChild(c);
/* Set Constant Properties */
ctx.shadowBlur = circle.blur;
ctx.shadowColor = &#39;hsla(&#39;+circle.hue+&#39;, 80%, 60%, 1)&#39;;
ctx.lineCap = &#39;round&#39;
var gradient1 = ctx.createLinearGradient(0, -circle.radius, 0, circle.radius);
gradient1.addColorStop(0, &#39;hsla(&#39;+circle.hue+&#39;, 60%, 50%, .25)&#39;);
gradient1.addColorStop(1, &#39;hsla(&#39;+circle.hue+&#39;, 60%, 50%, 0)&#39;);
var gradient2 = ctx.createLinearGradient(0, -circle.radius, 0, circle.radius);
gradient2.addColorStop(0, &#39;hsla(&#39;+circle.hue+&#39;, 100%, 50%, 0)&#39;);
gradient2.addColorStop(.1, &#39;hsla(&#39;+circle.hue+&#39;, 100%, 100%, .7)&#39;);
gradient2.addColorStop(1, &#39;hsla(&#39;+circle.hue+&#39;, 100%, 50%, 0)&#39;);
/* Loop It, Loop It Good */
setInterval(loop, 16);
  </script>
</body>
</html>
 -

Related recommendations:

Canvas Bessel formula derivation and objects following complex curve trajectories

Two JS methods to realize the parabolic trajectory motion of the ball

Realization of circular motion trajectory in css3 animation

The above is the detailed content of CSS and JS realize the beautiful starry sky trajectory movement effect. For more information, please follow other related articles on the PHP Chinese website!

css css3 JS canvas
Statement：
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Previous article：Detailed explanation of CSS code refactoringNext article：Detailed explanation of CSS code refactoring

Related articles

See more