Canvas 实现七彩喷泉

时间：2021-12-22 05:04:52
<!DOCTYPE html>

<html>

<head>

    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

    <title>小球 喷泉运动</title>

    <meta name="Keywords" content="关键词1,关键词2">

    <meta name="description" content="果断，是一种教养和能力">

    <!--响应式mate标签-->

    <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no, minimal-ui">

    <meta name="apple-mobile-web-app-capable" content="yes">

    <meta name="apple-mobile-web-app-status-bar-style" content="black">

    <style>

        * {

            padding:0;margin:0;

        }

        body{font-size: 14px;}

    </style>

</head>

<body>

    <canvas id="canvas"></canvas>

    <script type="text/javascript">

        window.onload = function(){

            var canvas = document.getElementById("canvas");

            var context = canvas.getContext("2d");

            //定义画布样式

            canvas.width = window.innerWidth;

            canvas.height = window.innerHeight;

            canvas.style.background = "#333";

            var cw = canvas.width;

            var ch = canvas.height;

            //定义小球个数

            var ballNum = 360;

            var r = 0.2;

            //

            var balls = [];

            for(var i=0;i<ballNum;i++){

                var ball = new Ball();

                ball.x = cw/2;

                ball.y = ch;

                ball.vy = Math.random()*-10-10;

                ball.vx = Math.random()*2-1;

                ball.color = getRgb16();

                ball.radius = rangeRandom(1,6);

                balls.push(ball);

            }

            function drawCanvas(ball){

                cw = window.innerWidth;

                ch = window.innerHeight;

                //每个小球方向的改变

                ball.vy += r;

                //每个小球的位置

                ball.x += ball.vx;

                ball.y += ball.vy;

                ball.color = getRgb16();

                ball.radius = rangeRandom(1,6);

                //边界的控制

                if(ball.y-ball.radius > ch ||

                        ball.y+ball.radius<0 ||

                        ball.x-ball.radius > cw ||

                        ball.x+ball.radius<0

                ){

                    //从新初始化

                    ball.x = cw/2;

                    ball.y = ch;

                    ball.vy = Math.random()*-10-10;

                    ball.vx = Math.random()*2-1;

                }

                ball.draw(context);

            }

            setInterval(function () {

                context.clearRect(0,0,cw,ch);

                balls.forEach(function(ball){

                    drawCanvas(ball);

                });

            },33);

        };

        function Ball(){

            this.x = 0;

            this.y = 0;

            this.vx = 0;

            this.vy = 0;

            this.radius = 6;

        }

        Ball.prototype.draw = function(context){

            context.beginPath();

            context.fillStyle = this.color;

            context.arc(this.x,this.y,this.radius,0,Math.PI*2);

            context.fill();

        };

        function getRgb(){

            //0-255

            var r = tRandom(256);

            var g = tRandom(256);

            var b = tRandom(256);

            return "rgb("+r+","+g+","+b+")";

        }

        function getRgb16(){

            //0-255

            var r = tRandom(256).toString(16);

            var g = tRandom(256).toString(16);

            var b = tRandom(256).toString(16);

            if(r.length<2)r=r+""+r;

            if(g.length<2)g=g+""+g;

            if(b.length<2)b=b+""+b;

            return "#"+r+""+g+""+b;

        }

        function rangeRandom(start,end){

            return Math.floor(Math.random()*(end-start+1)+start);

        }

        function tRandom(start){

            return Math.floor(Math.random()*start);

        }

    </script>

</body>

</html>

效果图：

Canvas 实现七彩喷泉

IT技术和行业交流群 417691667

相关文章