HTML5 Canvas实现3D色相球动画的JavaScript实例

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<title>JS canvas标签制作色相球</title>
</head>
<body>
<canvas></canvas>
<script type="text/javascript">
var canvas,ctx,max,p,count;
window.onload=function(){
 var a,b,r;
 canvas = document.getElementsByTagName('canvas')[0];
 ctx = canvas.getContext('2d');
 canvas.width=canvas.height=400;
 ctx.fillRect(0,0,400,400);
 max=80;
 count=150;
 p=[];
 r=0;
 for(a=0;a<max;a++){
  p.push([Math.cos(r),Math.sin(r),0]);
  r+=Math.PI*2/max;
 }
 for(a=0;a<max;a++)p.push([0,p[a][0],p[a][1]]);
 for(a=0;a<max;a++)p.push([p[a][1],0,p[a][0]]);
 rus();
};
function rus(){
 var a,b,c,d,e,s,tim,p2,xp,yp,xp2,yp2,x,y,z,x1,y1,z1;
 ctx.globalCompositeOperation = "source-over";
 ctx.fillStyle="rgba(0,0,0,0.03)";
 ctx.fillRect(0,0,canvas.width,canvas.height);
 ctx.globalCompositeOperation = "lighter";
 tim=count/5;
 for(e=0;e<3;e++){
  tim*=1.7;
  s=1-e/3;
  a=tim/59;
  yp=Math.cos(a);
  yp2=Math.sin(a);
  a=tim/23;
  xp=Math.cos(a);
  xp2=Math.sin(a);
  p2=[];
  for(a=0;a<p.length;a++){
   x=p[a][0];y=p[a][1];z=p[a][2];
   y1=y*yp+z*yp2;
   z1=y*yp2-z*yp;
   x1=x*xp+z1*xp2;
   z=x*xp2-z1*xp;
   z1=Math.pow(2,z*s);
   x=x1*z1;
   y=y1*z1;
   p2.push([x,y,z]);
  }
  s*=120;
  for(d=0;d<3;d++){
   for(a=0;a<max;a++){
    b=p2[d*max+a];
    c=p2[((a+1)%max)+d*max];
    ctx.beginPath();
    ctx.strokeStyle="hsla("+((a/max*360)|0)+",70%,60%,0.15)";
    ctx.lineWidth=Math.pow(6,b[2]);
    ctx.lineTo(b[0]*s+200,b[1]*s+200);
    ctx.lineTo(c[0]*s+200,c[1]*s+200);
    ctx.stroke();
   }
  }
 }
 count++;
 requestAnimationFrame(rus);
}
</script>
</body>
</html>