特效描述：html5 canvas 粒子波浪动画特效。html5基于canvas绘制波涛汹涌的粒子波浪动画。

代码结构

1. HTML代码

'use strict';

var FastRandom = function()

{

this.getNextFloat = function()

{

return Math.random();

};

};

var ParticleWave = function()

{

var me = this;

var config = {

colors : {

background : 0x000000,

particle : 0x477cc2

},

alpha : {

particle : 1

},

particleCount : 30000

};

var TAU = Math.PI * 2;

var random = new FastRandom();

var particle;

var particleFillStyle;

var particleColorRGB = new Float32Array(3);

var smoothGradient;

var waterGradient;

var canvas;

var engine;

var width;

var height;

var particleWaveWalker = 0;

var randomWalker = 0;

var requestTick = function()

{

window.requestAnimationFrame(tick);

};

var initParticle = function()

{

particle = new Float32Array(config.particleCount * 2);

eachParticle(function(x, z) {

particle[x] = random.getNextFloat();

particle[z] = random.getNextFloat();

});

};

var initCanvas = function()

{

var cs = document.getElementsByTagName('canvas');

canvas = cs[0];

engine = canvas.getContext('2d');

width = window.innerWidth;

height = window.innerHeight;

canvas.setAttribute('width', width);

canvas.setAttribute('height', height);

};

var initParticleColor = function()

{

particleColorRGB[0] = config.colors.particle >> 16 & 0xff;

particleColorRGB[1] = config.colors.particle >> 8 & 0xff;

particleColorRGB[2] = config.colors.particle & 0xff;

particleFillStyle = 'rgb(' + particleColorRGB[0] + ',' + particleColorRGB[1] + ',' + particleColorRGB[2] + ')';

};

var initSmoothGradient = function()

{

smoothGradient = engine.createLinearGradient(

width / 2,

0,

width / 2,

height

);

smoothGradient.addColorStop(0.25, 'rgba(0, 0, 0, 0)');

smoothGradient.addColorStop(0.45, 'rgba(0, 0, 0, 0.9)');

smoothGradient.addColorStop(0.5 , 'rgba(0, 0, 0, 1)');

smoothGradient.addColorStop(0.55, 'rgba(0, 0, 0, 0.9)');

smoothGradient.addColorStop(0.75, 'rgba(0, 0, 0, 0)');

};

var initWaterGradient = function()

{

waterGradient = engine.createLinearGradient(

width / 2,

height / 2,

width / 2,

height

);

waterGradient.addColorStop(0, 'rgba(0, 0, 30, 0)');

waterGradient.addColorStop(1, 'rgba(30, 0, 60, 0.5)');

};

var init = function()

{

initCanvas();

initParticle();

initParticleColor();

initSmoothGradient();

initWaterGradient();

};

var eachParticle = function(cb)

{

for (var i = 0; i < particle.length; i += 2) {

cb(i, i + 1);

}

};

var renderParticle = function()

{

randomWalker += (Math.random() - 0.5) * 0.1;

particleWaveWalker += 0.03;

var radius = {

min : 1,

add : 5

};

var midY = height / 2;

var midX = width / 2;

var spreadX = 5;

var spreadZ = 0.0;

var modZ = 0.0;

var addX = 0;

var addY = 0;

var p = {

x : 0.0,

y : 0.0,

r : 0.0

};

engine.fillStyle = particleFillStyle;

// engine.beginPath();

var waveControl = 10;

for (var i = 0, xIndex, zIndex; i < particle.length; i += 2) {

xIndex = i;

zIndex = i + 1;

particle[zIndex] += 0.003;

if (particle[zIndex] > 1) {

particle[zIndex] = 0;

particle[xIndex] = random.getNextFloat();

}

if (particle[zIndex] < 0.3) {

continue;

}

modZ = Math.pow(particle[zIndex], 2);

spreadZ = 1 + (spreadX - 1) * modZ;

//bottom

addX = (0.5 - particle[xIndex]) * width * spreadZ;

addY = midY * modZ * (1 + 3 / waveControl);

p.x = midX + addX;

p.y = midY + addY;

p.r = radius.min + modZ * radius.add;

p.y += Math.sin(particle[xIndex] * 50 + particleWaveWalker) * addY / waveControl;

p.y += Math.cos(particle[zIndex] * 10 + particleWaveWalker) * addY / waveControl;

p.y -= Math.cos(particle[zIndex] + particle[xIndex] * 10 + particleWaveWalker) * addY / waveControl;

p.y -= Math.cos(particle[xIndex] * 50 + particleWaveWalker) * addY / waveControl;

p.y -= Math.sin(particle[zIndex] * 10 + particleWaveWalker) * addY / waveControl;

if (p.x < 0 || p.x > width) {

continue;

}

engine.fillRect(p.x, p.y, p.r, p.r);

// engine.moveTo(p.x, p.y);

// engine.arc(p.x, p.y, p.r, 0, TAU);

//top

// p.y = height - p.y;

//

// engine.moveTo(p.x, p.y);

// engine.arc(p.x, p.y, p.r, 0, TAU);

}

engine.fillStyle = particleFillStyle;

// engine.closePath();

// engine.fill();

};

var colorIntToHexString = function(color)

{

var s = color.toString(16);

return '0'.repeat(6 - s.length) + s;

};

var clear = function()

{

engine.fillStyle = '#' + colorIntToHexString(config.colors.background);

engine.fillRect(0, 0, width, height);

};

var drawSmooth = function()

{

engine.fillStyle = smoothGradient;

engine.fillRect(0, 0, width, height);

};

var drawWater = function()

{

engine.fillStyle = waterGradient;

engine.fillRect(0, height / 2, width, height / 2);

};

var tick = function()

{

clear();

drawWater();

renderParticle();

drawSmooth();

requestTick();

};

this.run = function()

{

init();

tick();

};

};

var pw = new ParticleWave();

pw.run();