HTML5 Canvas实现烟花绽放特效
本文为大家带来了一款，免费而又安全环保的HTML5 Canvas实现的放烟花特效。
效果如下：
代码如下：
XML/HTML Code复制内容到剪贴板 <!DOCTYPE HTML> <html> <head> <title>Canvas 实现放烟花特效</title> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width,height=device-height,inital-scale=1.0,maximum-scale=1.0,user-scalable=no"> <style type="text/css"> html,body{height:100%;margin:0;padding:0} ul,li{text-indent:0;text-decoration:none;margin:0;padding:0} img{border:0} body{background-color:#000;color:#999;font:100%/18px helvetica, arial, sans-serif} canvas{cursor:crosshair;display:block;left:0;position:absolute;top:0;z-index:20} #header img{width:100%; height:20%;} #bg img{width:100%; height:80%;} #header,#bg{position:fixed;left:0;right:0;z-index:10} #header{top:0} #bg{position:fixed;z-index:1;bottom:0} audio{position:fixed;display:none;bottom:0;left:0;right:0;width:100%;z-index:5} </style> </head> <body> <div id="bg"> <img id="bgimg" src="http://img.ivsky.com/img/tupian/pre/201508/02/yuzhou_xingkong_yu_yueliang-006.jpg"> </div> <script src="http://cdn.bootcss.com/jquery/2.2.0/jquery.min.js"></script> <script> $(function(){ var Fireworks = function(){ var self = this; // 产生烟花随机数 var rand = function(rMi, rMa){ //按位取反运算符 return ~~((Math.random()*(rMa-rMi+1))+rMi); },hitTest = function(x1, y1, w1, h1, x2, y2, w2, h2){ return !(x1 + w1 < x2 || x2 + w2 < x1 || y1 + h1 < y2 || y2 + h2 < y1); }; //请求动画帧 window.requestAnimFrame=function(){ return window.requestAnimationFrame ||window.webkitRequestAnimationFrame ||window.mozRequestAnimationFrame ||window.oRequestAnimationFrame ||window.msRequestAnimationFrame ||function(callback){ window.setTimeout(callback,1000/60); } }(); self.init = function(){ self.canvas = document.createElement('canvas'); //canvas 全屏 selfself.canvas.width = self.cw = $(window).innerWidth(); selfself.canvas.height = self.ch = $(window).innerHeight(); self.particles = []; self.partCount = 150; self.fireworks = []; selfself.mx = self.cw/2; selfself.my = self.ch/2; self.currentHue = 30; self.partSpeed = 5; self.partSpeedVariance = 10; self.partWind = 50; self.partFriction = 5; self.partGravity = 1; self.hueMin = 0; self.hueMax = 360; self.fworkSpeed = 4; self.fworkAccel = 10; self.hueVariance = 30; self.flickerDensity = 25; self.showShockwave = true; self.showTarget = false; self.clearAlpha = 25; $(document.body).append(self.canvas); selfself.ctx = self.canvas.getContext('2d'); self.ctx.lineCap = 'round'; self.ctx.lineJoin = 'round'; self.lineWidth = 1; self.bindEvents(); self.canvasLoop(); self.canvas.onselectstart = function() { return false; }; }; // 创建粒子 self.createParticles = function(x,y, hue){ var countdown = self.partCount; while(countdown--){ var newParticle = { x: x, y: y, coordLast: [ {x: x, y: y}, {x: x, y: y}, {x: x, y: y} ], angle: rand(0, 360), speed: rand(((self.partSpeed - self.partSpeedVariance) <= 0) ? 1 : self.partSpeed - self.partSpeedVariance, (self.partSpeed + self.partSpeedVariance)), friction: 1 - self.partFriction/100, gravity: self.partGravity/2, hue: rand(hue-self.hueVariance, hue+self.hueVariance), brightness: rand(50, 80), alpha: rand(40,100)/100, decay: rand(10, 50)/1000, wind: (rand(0, self.partWind) - (self.partWind/2))/25, lineWidth: self.lineWidth }; self.particles.push(newParticle); } }; // 更新粒子 self.updateParticles = function(){ var i = self.particles.length; while(i--){ var p = self.particles[i]; var radians = p.angle * Math.PI / 180; var vx = Math.cos(radians) * p.speed; var vy = Math.sin(radians) * p.speed; p.speed *= p.friction; p.coordLast[2].x = p.coordLast[1].x; p.coordLast[2].y = p.coordLast[1].y; p.coordLast[1].x = p.coordLast[0].x; p.coordLast[1].y = p.coordLast[0].y; p.coordLast[0].x = p.x; p.coordLast[0].y = p.y; p.x += vx; p.y += vy; p.y += p.gravity; p.angle += p.wind; p.alpha -= p.decay; if(!hitTest(0,0,self.cw,self.ch,p.x-p.radius, p.y-p.radius, p.radius*2, p.radius*2) || p.alpha < .05){ self.particles.splice(i, 1); } }; }; // 绘制粒子 self.drawParticles = function(){ var i = self.particles.length; while(i--){ var p = self.particles[i]; var coordRand = (rand(1,3)-1); self.ctx.beginPath(); self.ctx.moveTo(Math.round(p.coordLast[coordRand].x), Math.round(p.coordLast[coordRand].y)); self.ctx.lineTo(Math.round(p.x), Math.round(p.y)); self.ctx.closePath(); self.ctx.strokeStyle = 'hsla('+p.hue+', 100%, '+p.brightness+'%, '+p.alpha+')'; self.ctx.stroke(); if(self.flickerDensity > 0){ var inverseDensity = 50 - self.flickerDensity; if(rand(0, inverseDensity) === inverseDensity){ self.ctx.beginPath(); self.ctx.arc(Math.round(p.x), Math.round(p.y), rand(p.lineWidth,p.lineWidth+3)/2, 0, Math.PI*2, false) self.ctx.closePath(); var randrandAlpha = rand(50,100)/100; self.ctx.fillStyle = 'hsla('+p.hue+', 100%, '+p.brightness+'%, '+randAlpha+')'; self.ctx.fill(); } } }; }; // 创建烟花 self.createFireworks = function(startX, startY, targetX, targetY){ var newFirework = { x: startX, y: startY, startX: startX, startY: startY, hitX: false, hitY: false, coordLast: [ {x: startX, y: startY}, {x: startX, y: startY}, {x: startX, y: startY} ], targetX: targetX, targetY: targetY, speed: self.fworkSpeed, angle: Math.atan2(targetY - startY, targetX - startX), shockwaveAngle: Math.atan2(targetY - startY, targetX - startX)+(90*(Math.PI/180)), acceleration: self.fworkAccel/100, hue: self.currentHue, brightness: rand(50, 80), alpha: rand(50,100)/100, lineWidth: self.lineWidth }; self.fireworks.push(newFirework); }; // 更新烟花 self.updateFireworks = function(){ var i = self.fireworks.length; while(i--){ var f = self.fireworks[i]; self.ctx.lineWidth = f.lineWidth; vx = Math.cos(f.angle) * f.speed, vy = Math.sin(f.angle) * f.speed; f.speed *= 1 + f.acceleration; f.coordLast[2].x = f.coordLast[1].x; f.coordLast[2].y = f.coordLast[1].y; f.coordLast[1].x = f.coordLast[0].x; f.coordLast[1].y = f.coordLast[0].y; f.coordLast[0].x = f.x; f.coordLast[0].y = f.y; if(f.startX >= f.targetX){ if(f.x + vx <= f.targetX){ ff.x = f.targetX; f.hitX = true; } else { f.x += vx; } } else { if(f.x + vx >= f.targetX){ ff.x = f.targetX; f.hitX = true; } else { f.x += vx; } } if(f.startY >= f.targetY){ if(f.y + vy <= f.targetY){ ff.y = f.targetY; f.hitY = true; } else { f.y += vy; } } else { if(f.y + vy >= f.targetY){ ff.y = f.targetY; f.hitY = true; } else { f.y += vy; } } if(f.hitX && f.hitY){ self.createParticles(f.targetX, f.targetY, f.hue); self.fireworks.splice(i, 1); } }; }; // 绘制烟花 self.drawFireworks = function(){ var i = self.fireworks.length; self.ctx.globalCompositeOperation = 'lighter'; while(i--){ var f = self.fireworks[i]; self.ctx.lineWidth = f.lineWidth; var coordRand = (rand(1,3)-1); self.ctx.beginPath(); self.ctx.moveTo(Math.round(f.coordLast[coordRand].x), Math.round(f.coordLast[coordRand].y)); self.ctx.lineTo(Math.round(f.x), Math.round(f.y)); self.ctx.closePath(); self.ctx.strokeStyle = 'hsla('+f.hue+', 100%, '+f.brightness+'%, '+f.alpha+')'; self.ctx.stroke(); if(self.showTarget){ self.ctx.save(); self.ctx.beginPath(); self.ctx.arc(Math.round(f.targetX), Math.round(f.targetY), rand(1,8), 0, Math.PI*2, false) self.ctx.closePath(); self.ctx.lineWidth = 1; self.ctx.stroke(); self.ctx.restore(); } if(self.showShockwave){ self.ctx.save(); self.ctx.translate(Math.round(f.x), Math.round(f.y)); self.ctx.rotate(f.shockwaveAngle); self.ctx.beginPath(); self.ctx.arc(0, 0, 1*(f.speed/5), 0, Math.PI, true); self.ctx.strokeStyle = 'hsla('+f.hue+', 100%, '+f.brightness+'%, '+rand(25, 60)/100+')'; self.ctx.lineWidth = f.lineWidth; self.ctx.stroke(); self.ctx.restore(); } }; }; // 绑定事件 self.bindEvents = function(){ $(window).on('resize', function(){ clearTimeout(self.timeout); self.timeout = setTimeout(function() { selfself.canvas.width = self.cw = $(window).innerWidth(); selfself.canvas.height = self.ch = $(window).innerHeight(); self.ctx.lineCap = 'round'; self.ctx.lineJoin = 'round'; }, 100); }); $(self.canvas).on('mousedown', function(e){ self.mx = e.pageX - self.canvas.offsetLeft; self.my = e.pageY - self.canvas.offsetTop; self.currentHue = rand(self.hueMin, self.hueMax); self.createFireworks(self.cw/2, self.ch, self.mx, self.my); $(self.canvas).on('mousemove.fireworks', function(e){ self.mx = e.pageX - self.canvas.offsetLeft; self.my = e.pageY - self.canvas.offsetTop; self.currentHue = rand(self.hueMin, self.hueMax); self.createFireworks(self.cw/2, self.ch, self.mx, self.my); }); }); $(self.canvas).on('mouseup', function(e){ $(self.canvas).off('mousemove.fireworks'); }); }; self.clear = function(){ self.particles = []; self.fireworks = []; self.ctx.clearRect(0, 0, self.cw, self.ch); }; self.canvasLoop = function(){ requestAnimFrame(self.canvasLoop, self.canvas); self.ctx.globalCompositeOperation = 'destination-out'; self.ctx.fillStyle = 'rgba(0,0,0,'+self.clearAlpha/100+')'; self.ctx.fillRect(0,0,self.cw,self.ch); self.updateFireworks(); self.updateParticles(); self.drawFireworks(); self.drawParticles(); }; self.init(); } var fworks = new Fireworks(); $('#info-toggle').on('click', function(e){ $('#info-inner').stop(false, true).slideToggle(100); e.preventDefault(); }); }); </script> <canvas width="1400" height="449"></canvas> </body> </html>是不是被HTML5强大的效果惊呆了，一饱眼福了吧。
