How to use Canvas to realize the special effect of fireworks in HTML5
这篇文章主要介绍"HTML5中怎么用Canvas实现烟花绽放特效"，在日常操作中，相信很多人在HTML5中怎么用Canvas实现烟花绽放特效问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答"HTML5中怎么用Canvas实现烟花绽放特效"的疑惑有所帮助!接下来，请跟着小编一起来学习吧!
代码如下：
XML/HTML Code复制内容到剪贴板
Canvas 实现放烟花特效
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}
$(function(){
var Fireworks = function(){
var self = this;
//generate random number of fireworks
var rand = function(rMi, rMa){
//bitwise negation operator
return ~~((Math.random()*(rMa-rMi+1))+rMi);
},hitTest = function(x1, y1, w1, h2, x2, y2, w2, h3){
return ! (x1 + w1
< x2 || x2 + w2 < x1 || y1 + h2 < y2 || y2 + h3 < 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){ 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;
}
}
if(f.startY >= f.targetY){
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();
});
});
到此，关于"HTML5中怎么用Canvas实现烟花绽放特效"的学习就结束了，希望能够解决大家的疑惑。理论与实践的搭配能更好的帮助大家学习，快去试试吧!若想继续学习更多相关知识，请继续关注网站，小编会继续努力为大家带来更多实用的文章!
