實例詳解jQuery與HTML5實現WebGL高性能煙火綻放動畫效果-js教程-PHP中文網

本文主要介紹了jQuery+HTML5實現WebGL高性能煙火綻放動畫效果,可實現煙火升空爆炸的絢麗動畫效果,完成以後非常好看，希望能幫助到大家掌握jQuery和HTML5實現WebGL高性能煙火綻放動畫效果。
運行效果：
完整程式碼如下：
<!DOCTYPE html>
<html class=" -webkit- js flexbox canvas canvastext webgl no-touch geolocation postmessage websqldatabase indexeddb hashchange history draganddrop websockets rgba hsla multiplebgs backgroundsize borderimage borderradius boxshadow textshadow opacity cssanimations csscolumns cssgradients cssreflections csstransforms csstransforms3d csstransitions fontface generatedcontent video audio localstorage sessionstorage webworkers applicationcache svg inlinesvg smil svgclippaths">
<head>
<meta charset="UTF-8">
<meta name="viewport" content=" initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
<meta name="format-detection" content="telephone=no">
<title>HTML5/WebGL高性能烟花绽放动画</title>
<meta name="description" content="HTML5/WebGL高性能烟花绽放动画">
<meta name="keywords" content="HTML5/WebGL高性能烟花绽放动画">
<style>
canvas {
  position: absolute;
  top: 0;
  left: 0;
  background-color: #111;
}
</style>
</head>
<body>
<script src="jquery-1.11.1.min.js"></script>
<canvas id="c" width="1440" height="304"></canvas><script src="prefixfree.min.js"></script><script src="modernizr.js"></script><script>var gl = c.getContext(&#39;webgl&#39;, {
    preserveDrawingBuffer: true
  }),
  w = c.width = window.innerWidth,
  h = c.height = window.innerHeight
, webgl = {}, opts = {
  projectileAlpha: .8,
  projectileLineWidth: 1.3,
  fireworkAngleSpan: .5,
  baseFireworkVel: 3,
  addedFireworkVel: 3,
  gravity: .03,
  lowVelBoundary: -.2,
  xFriction: .995,
  baseShardVel: 1,
  addedShardVel: .2,
  fireworks: 1000,
  baseShardsParFirework: 10,
  addedShardsParFirework: 10,
  shardFireworkVelMultiplier: .3,
  initHueMultiplier: 1 / 360,
  runHueAdder: .1 / 360
}
webgl.vertexShaderSource = `
uniform int u_mode;
uniform vec2 u_res;
attribute vec4 a_data;
varying vec4 v_color;
vec3 h2rgb( float h ){
 return clamp( abs( mod( h * 6. + vec3( 0, 4, 2 ), 6. ) - 3. ) -1., 0., 1. );
}
void clear(){
 gl_Position = vec4( a_data.xy, 0, 1 );
 v_color = vec4( 0, 0, 0, a_data.w );
}
void draw(){
 gl_Position = vec4( vec2( 1, -1 ) * ( ( a_data.xy / u_res ) * 2. - 1. ), 0, 1 );
 v_color = vec4( h2rgb( a_data.z ), a_data.w );
}
void main(){
 if( u_mode == 0 )
 draw();
 else
 clear();
}
`;
webgl.fragmentShaderSource = `
precision mediump float;
varying vec4 v_color;
void main(){
 gl_FragColor = v_color;
}
`;
webgl.vertexShader = gl.createShader(gl.VERTEX_SHADER);
gl.shaderSource(webgl.vertexShader, webgl.vertexShaderSource);
gl.compileShader(webgl.vertexShader);
webgl.fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
gl.shaderSource(webgl.fragmentShader, webgl.fragmentShaderSource);
gl.compileShader(webgl.fragmentShader);
webgl.shaderProgram = gl.createProgram();
gl.attachShader(webgl.shaderProgram, webgl.vertexShader);
gl.attachShader(webgl.shaderProgram, webgl.fragmentShader);
gl.linkProgram(webgl.shaderProgram);
gl.useProgram(webgl.shaderProgram);
webgl.dataAttribLoc = gl.getAttribLocation(webgl.shaderProgram, &#39;a_data&#39;);
webgl.dataBuffer = gl.createBuffer();
gl.enableVertexAttribArray(webgl.dataAttribLoc);
gl.bindBuffer(gl.ARRAY_BUFFER, webgl.dataBuffer);
gl.vertexAttribPointer(webgl.dataAttribLoc, 4, gl.FLOAT, false, 0, 0);
webgl.resUniformLoc = gl.getUniformLocation(webgl.shaderProgram, &#39;u_res&#39;);
webgl.modeUniformLoc = gl.getUniformLocation(webgl.shaderProgram, &#39;u_mode&#39;);
gl.viewport(0, 0, w, h);
gl.uniform2f(webgl.resUniformLoc, w, h);
gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA);
gl.enable(gl.BLEND);
gl.lineWidth(opts.projectileLineWidth);
webgl.data = [];
webgl.clear = function() {
  gl.uniform1i(webgl.modeUniformLoc, 1);
  var a = .1;
  webgl.data = [-1, -1, 0, a,
    1, -1, 0, a, -1, 1, 0, a, -1, 1, 0, a,
    1, -1, 0, a,
    1, 1, 0, a
  ];
  webgl.draw(gl.TRIANGLES);
  gl.uniform1i(webgl.modeUniformLoc, 0);
  webgl.data.length = 0;
}
webgl.draw = function(glType) {
  gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(webgl.data), gl.STATIC_DRAW);
  gl.drawArrays(glType, 0, webgl.data.length / 4);
}
var fireworks = [],
  tick = 0,
  sins = [],
  coss = [],
  maxShardsParFirework = opts.baseShardsParFirework + opts.addedShardsParFirework,
  tau = 6.283185307179586476925286766559;
for (var i = 0; i < maxShardsParFirework; ++i) {
  sins[i] = Math.sin(tau * i / maxShardsParFirework);
  coss[i] = Math.cos(tau * i / maxShardsParFirework);
}
function Firework() {
  this.reset();
  this.shards = [];
  for (var i = 0; i < maxShardsParFirework; ++i)
    this.shards.push(new Shard(this));
}
Firework.prototype.reset = function() {
  var angle = -Math.PI / 2 + (Math.random() - .5) * opts.fireworkAngleSpan,
    vel = opts.baseFireworkVel + opts.addedFireworkVel * Math.random();
  this.mode = 0;
  this.vx = vel * Math.cos(angle);
  this.vy = vel * Math.sin(angle);
  this.x = Math.random() * w;
  this.y = h;
  this.hue = tick * opts.initHueMultiplier;
}
Firework.prototype.step = function() {
  if (this.mode === 0) {
    var ph = this.hue,
      px = this.x,
      py = this.y;
    this.hue += opts.runHueAdder;
    this.x += this.vx *= opts.xFriction;
    this.y += this.vy += opts.gravity;
    webgl.data.push(
      px, py, ph, opts.projectileAlpha * .2,
      this.x, this.y, this.hue, opts.projectileAlpha * .2);
    if (this.vy >= opts.lowVelBoundary) {
      this.mode = 1;
      this.shardAmount = opts.baseShardsParFirework + opts.addedShardsParFirework * Math.random() | 0;
      var baseAngle = Math.random() * tau,
        x = Math.cos(baseAngle),
        y = Math.sin(baseAngle),
        sin = sins[this.shardAmount],
        cos = coss[this.shardAmount];
      for (var i = 0; i < this.shardAmount; ++i) {
        var vel = opts.baseShardVel + opts.addedShardVel * Math.random();
        this.shards[i].reset(x * vel, y * vel)
        var X = x;
        x = x * cos - y * sin;
        y = y * cos + X * sin;
      }
    }
  } else if (this.mode === 1) {
    this.ph = this.hue
    this.hue += opts.runHueAdder;
    var allDead = true;
    for (var i = 0; i < this.shardAmount; ++i) {
      var shard = this.shards[i];
      if (!shard.dead) {
        shard.step();
        allDead = false;
      }
    }
    if (allDead)
      this.reset();
  }
}
function Shard(parent) {
  this.parent = parent;
}
Shard.prototype.reset = function(vx, vy) {
  this.x = this.parent.x;
  this.y = this.parent.y;
  this.vx = this.parent.vx * opts.shardFireworkVelMultiplier + vx;
  this.vy = this.parent.vy * opts.shardFireworkVelMultiplier + vy;
  this.starty = this.y;
  this.dead = false;
  this.tick = 1;
}
Shard.prototype.step = function() {
  this.tick += .05;
  var px = this.x,
    py = this.y;
  this.x += this.vx *= opts.xFriction;
  this.y += this.vy += opts.gravity;
  var proportion = 1 - (this.y - this.starty) / (h - this.starty);
  webgl.data.push(
    px, py, this.parent.ph, opts.projectileAlpha / this.tick,
    this.x, this.y, this.parent.hue, opts.projectileAlpha / this.tick);
  if (this.y > h)
    this.dead = true;
}
function anim() {
  window.requestAnimationFrame(anim)
  webgl.clear();
  ++tick;
  if (fireworks.length < opts.fireworks)
    fireworks.push(new Firework);
  fireworks.map(function(firework) {
    firework.step();
  });
  webgl.draw(gl.LINES);
}
anim();
window.addEventListener(&#39;resize&#39;, function() {
  w = c.width = window.innerWidth;
  h = c.height = window.innerHeight;
  gl.viewport(0, 0, w, h);
  gl.uniform2f(webgl.resUniformLoc, w, h);
})
window.addEventListener(&#39;click&#39;, function(e) {
  var firework = new Firework();
  firework.x = e.clientX;
  firework.y = e.clientY;
  firework.vx = 0;
  firework.vy = 0;
  fireworks.push(firework);
});
</script>
</body>
</html>
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