js实现canvas各式曲线动画效果代码-html代码-BFW代码库

代码语言：html

所属分类：动画

代码描述：js实现canvas各式曲线动画效果代码

下面为部分代码预览，完整代码请点击下载或在bfwstudio webide中打开

<!DOCTYPE html>
<html lang="en" >

<head>

  <meta charset="UTF-8">
  

  
  
  
  
<style>
body {
  font-family: Arial, Helvetica, "Liberation Sans", FreeSans, sans-serif;
  background-color: #000;
  margin:0;
  padding:0;
  border-width:0;
  cursor: pointer;
}
</style>


</head>

<body>
  


  
      <script >
"use strict";

window.addEventListener("load", function () {

  let nbDots, symm;

  let canv, ctx; // canvas and context
  let maxx, maxy; // canvas dimensions
  let xc, yc, lRef, lWidth;
  let tbSin, tbCos;

  // for animation
  let events;

  // shortcuts for Math.
  const mrandom = Math.random;
  const mfloor = Math.floor;
  const mround = Math.round;
  const mceil = Math.ceil;
  const mabs = Math.abs;
  const mmin = Math.min;
  const mmax = Math.max;

  const mPI = Math.PI;
  const mPIS2 = Math.PI / 2;
  const mPIS3 = Math.PI / 3;
  const m2PI = Math.PI * 2;
  const m2PIS3 = Math.PI * 2 / 3;
  const msin = Math.sin;
  const mcos = Math.cos;
  const matan2 = Math.atan2;

  const mhypot = Math.hypot;
  const msqrt = Math.sqrt;

  const rac3 = msqrt(3);
  const rac3s2 = rac3 / 2;

  //-----------------------------------------------------------------------------
  /*	============================================================================
  	This is based upon Johannes Baagoe's carefully designed and efficient hash
  	function for use with JavaScript.  It has a proven "avalanche" effect such
  	that every bit of the input affects every bit of the output 50% of the time,
  	which is good.	See: http://baagoe.com/en/RandomMusings/hash/avalanche.xhtml
  	============================================================================
  */
  /* This function returns a hash function depending on a seed.
  
  if no seed is provided (or a falsy value), Math.random() is used.
  The returned function always returns the same number in the range [0..1[ for the
  same value of the argument. This argument may be a String or a Number or anything else
  which can be 'toStringed'
  Two returned functions obtained with two equal seeds are equivalent.
  */

  function hashFunction(seed) {
    let n0 = 0xefc8249d;
    let n = n0;
    mash(seed || Math.random()); // pre-compute n for seed
    n0 = n; //

    function mash(data) {
      data = data.toString() + 'U';
      n = n0;
      for (let i = 0; i < data.length; i++) {
        n += data.charCodeAt(i);
        var h = 0.02519603282416938 * n;
        n = h >>> 0;
        h -= n;
        h *= n;
        n = h >>> 0;
        h -= n;
        n += h * 0x100000000; // 2^32
      } // for
      return (n >>> 0) * 2.3283064365386963e-10; // 2^-32
    } // mash
    return mash;
  } // hashFunction(seed)

  //------------------------------------------------------------------------

  function alea(mini, maxi) {
    // random number in given range

    if (typeof maxi == 'undefined') return mini * mrandom(); // range 0..mini

    return mini + mrandom() * (maxi - mini); // range mini..maxi
  }
  // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  function intAlea(mini, maxi) {
    // random integer in given range (mini..maxi - 1 or 0..mini - 1)
    //
    if (typeof maxi == 'undefined') return mfloor(mini * mrandom()); // range 0..mini - 1
    return mini + mfloor(mrandom() * (maxi - mini)); // range mini .. maxi - 1
  }
  // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

  function Noise1D(period, min = 0, max = 1, hash) {
    /* returns a 1D noise function.
       the (mandatory) hash function must return a value between 0 and 1. The hash function
       will be called with an integer number for a parameter.
      the returned function takes one parameter, and will always return the same value if called with the same parameter
      period should be > 1. The bigger period is, the smoother the output noise is
    
    suggestion : the hash parameter could be a function returned from a call to hashFunction above
    
    */

    let currx, y0, y1; // cached valued, to reduce number of calls to 'hash'
    let phase = hash(0); // to shift the phase of different generators between each other;

    return function (x) {
      let xx = x / period + phase;
      let intx = mfloor(xx);

      if (intx - 1 === currx) {// next integer interval
        ++currx;
        y0 = y1;
        y1 = min + (max - min) * hash(currx + 1);
      } else if (intx !== currx) {// unrelated interval
        currx = intx;
        y0 = min + (max - min) * hash(currx);
        y1 = min + (max - min) * hash(currx + 1);
      }
      let frac = xx - currx;
      let z = (3 - 2 * frac) * frac * frac;
      return z * y1 + (1 - z) * y0;
    };
  } // Noise1D
  //------------------------------------------------------------------------
  function Blob() {

    this.fxs = new Array(nbDots).fill(0).map(() => Noise1D(alea(15000, 30000), -1, 1, hashFunction()));
    this.fys = new Array(nbDots).fill(0).map(() => Noise1D(alea(15000, 30000), -1, 1, hashFunction()));
    this.hue = intAlea(360);
    this.dHue = Noise1D(alea(7000, 90000), -0.1, 0.1, hashFunction());

  } // Blob

  Blob.prototype.actu = function (t) {

    let dir, rad;
    let k0, k1, k2, k3;
    let x, y;

    this.nbDirs = nbDots * symm;
    this.points = [];

    let max = 0;

    for (let k = 0; k < nbDots; ++k) {
      x = this.fxs[k](t);
      y = this.fys[k](t);
      max = mmax(max, mhypot(x, y));
      this.points[k] = [x, y];
    } // for k
    max = mmax(max, 0.001); // .........完整代码请登录后点击上方下载按钮下载查看