Canvas 绘制粒子动画背景_H5之家 - 中国HTML5教程资源分享第一站

Canvas 绘制粒子动画背景

代码如下：

<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <style> *{ margin:0px; padding:0px; } body{ background:#000; } canvas{ position:absolute; width:100%; height:100%; } </style> <body> <canvas>您的浏览器不支持，请升级最新的版本!</canvas> <script>window.requestAnimFrame = ( function() { return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || function( callback ) { window.setTimeout( callback, 1000 / 60 ); }; })(); var can = document.getElementById("canvas"); var cxt = can.getContext("2d"); can.width = window.innerWidth; can.height = window.innerHeight; cxt.lineWidth = 0.3; //初始链接线条显示位置 var mousePosition = { x : 30*can.width/100, y : 30*can.height/100 } //圆形粒子对象参数 var dots = { n : 500,//圆形粒子个数 distance : 50,//圆形粒子之间的距离 d_radius : 80,//粒子距离鼠标点的距离 array : []//保存n个圆形粒子对象 } //创建随机颜色值 function colorValue(min){ return Math.floor(Math.random()*255 + min); } function createColorStyle(r,g,b){ return "rgba("+r+","+g+","+b+", 1)"; } //混合两个圆形粒子的颜色 function mixConnect(c1,r1,c2,r2){//圆的颜色半径 return (c1*r1+c2*r2)/(r1+r2); }; //生成线条的颜色 function lineColor(dot1,dot2){//获取具体的圆的颜色再计算 var color1 = dot1.color, color2 = dot2.color; var r = mixConnect(color1.r,dot1.radius,color2.r,dot2.radius); var g = mixConnect(color1.g,dot1.radius,color2.g,dot2.radius); var b = mixConnect(color1.b,dot1.radius,color2.b,dot2.radius); return createColorStyle(Math.floor(r),Math.floor(g),Math.floor(b)); } //生成圆形粒子的颜色对象 function Color(min){ min = min || 0; this.r = colorValue(min); this.g = colorValue(min); this.b = colorValue(min); this.style = createColorStyle(this.r,this.g,this.b); } //创建圆形粒子对象 function Dot(){ //圆形粒子随机圆心坐标点 this.x = Math.random()*can.width; this.y = Math.random()*can.height; //x y 方向运动的速度值 this.vx = -0.5 + Math.random(); this.vy = -0.5 + Math.random(); this.radius = Math.random()*5; //this.color = "#ff3333"; this.color = new Color(); } //绘制出圆形粒子 Dot.prototype.draw = function(){ cxt.beginPath(); cxt.fillStyle = this.color.style; cxt.arc(this.x,this.y,this.radius,0,Math.PI*2,false); cxt.fill(); } //添加圆形粒子 function createCircle(){ for (var i=0;i<dots.n ;i++ ) { dots.array.push(new Dot()); } } //绘制出圆形粒子 function drawDots(){ for (var i=0;i<dots.n ;i++ ) { var dot = dots.array[i]; dot.draw(); } } //drawDots(); //移动 function moveDots(){ for (var i=0;i<dots.n ;i++ ){ var dot = dots.array[i]; //当圆形粒子对象碰壁的时候就反弹回来 if (dot.y < 0 || dot.y > can.height) { dot.vx = dot.vx; dot.vy = -dot.vy; }else if (dot.x < 0 || dot.x > can.width) { dot.vx = -dot.vx; dot.vy = dot.vy; } //给圆形粒子圆心坐标加上速度值移动圆形粒子 dot.x += dot.vx; dot.y += dot.vy; } } //链接粒子对象 function connectDots(){ for (var i=0;i<dots.n ; i++) { for ( var j=0;j<dots.n ; j++) { iDot = dots.array[i]; jDot = dots.array[j]; if ((iDot.x - jDot.x) < dots.distance && (iDot.y - jDot.y) < dots.distance && (iDot.x - jDot.x) > -dots.distance && (iDot.y - jDot.y) > -dots.distance) { if ((iDot.x - mousePosition.x) < dots.d_radius && (iDot.y - mousePosition.y) < dots.d_radius && (iDot.x - mousePosition.x) > -dots.d_radius && (iDot.y - mousePosition.y) > -dots.d_radius) { cxt.beginPath(); //cxt.strokeStyle = "yellow"; cxt.strokeStyle = lineColor(iDot,jDot); cxt.moveTo(iDot.x,iDot.y); cxt.lineTo(jDot.x,jDot.y); cxt.closePath(); cxt.stroke(); } } } } } createCircle(); //让圆形粒子不断的移动 function animateDots(){ cxt.clearRect(0,0,can.width,can.height); moveDots(); connectDots() drawDots(); requestAnimFrame(animateDots); } animateDots(); can.onmousemove = function(ev){ var ev = ev || window.event; mousePosition.x = ev.pageX; mousePosition.y = ev.pageY; } can.onmouseout = function(){ mousePosition.x = can.width/2; mousePosition.y = can.height/2; } </script> </body> </html>

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