JavaScript 火焰

港控/mmm° 2022-07-13 13:41 123阅读 0赞

<html>
        <head>
            <meta charset="utf8" />
            <title>火焰效果</title>
            <style type="text/css"> body { background-color:black; } p { color:white; text-align:center; } #canvas { border:1px dashed #333; display:block; margin:0 auto; background-color:black; } </style>
        </head>
        <body>
            <script> var vendors = ["", "ms", "moz", "webkit", "o"]; for (var i=0; i<vendors.length; i++) { var key = vendors[i] + "RequestAnimationFrame"; if(window[key]) { console.log(key + "<br/>"); } key = vendors[i] + "CancelAnimationFrame"; if(window[key]) { console.log(key + "<br/>"); } key = vendors[i] + "CancelRequestAnimationFrame"; if(window[key]) { console.log(key + "<br/>"); } } </script>
            <canvas id="canvas" width="320px" height="480px">您的浏览器不支持canvas</canvas>
            <p>低俗的人一定没有高雅需求，高雅的人往往会有低俗的需求</p>
            <script type="text/javascript"> var c = document.getElementById("canvas"); var ctx = c.getContext("2d"); //自动调整渲染间隔，来最佳匹配60fps。同时当标签不可见时暂停渲染 function setupRAF() { window.requestAnimationFrame = ( window.requestAnimationFrame || window.webkitRequestAnimationsFrame || window.msRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame ); } //清除画布上的内容 function clearCanvas() { ctx.globalCompositeOperation = "source-over"; ctx.clearRect(0, 0, c.width, c.height); } var CanvasController = function() { //火焰粒子 var FireParticle = function(locationX, locationY, speedX, speedY) { this.location = { x: locationX, y: locationY, } //半径 this.radius = .5 + Math.random() * 1; //颜色 this.color = { r: 255, g: Math.round(Math.random() * 150), b: 0, } //速度 this.speed = { x: (-1 + Math.random() * 2) + speedX, y: (Math.random() - 1) * speedY, }; //生命总值 this.healthPoint = 10 + Math.random() * 10; //当前生命值 this.hp = this.healthPoint; //将各个颜色分量组成颜色值 this.makeupColor = function(opacity) { return "rgba(" + this.color.r + "," + this.color.g + "," + this.color.b + "," + opacity + ")"; } //更新 this.update = function() { this.location.x += this.speed.x; this.location.y += this.speed.y; this.hp--; this.radius++; } //渲染 this.render = function() { ctx.beginPath(); var opacity = Math.round(this.hp / this.healthPoint * 100) / 100; var gradient = ctx.createRadialGradient(this.location.x, this.location.y, 0, this.location.x, this.location.y, this.radius); gradient.addColorStop(0, this.makeupColor(opacity)); gradient.addColorStop(0.5, this.makeupColor(opacity)); gradient.addColorStop(1, this.makeupColor(0)); ctx.fillStyle = gradient; ctx.arc(this.location.x, this.location.y, this.radius, 0, 2 * Math.PI); ctx.fill(); } } //火焰 var Fire = function(locationX, locationY, speedX, speedY) { var count = Math.round(30 * speedY); //火焰粒子数组 var particles = []; for(var i=0; i<count; i++) { particles.push(new FireParticle(locationX, locationY, speedX, speedY)); } //更新 this.update = function() { for(var i=0; i < particles.length; i++) { particles[i].update(); if(particles[i].hp < 0) { particles[i] = new FireParticle(locationX, locationY, speedX, speedY); } } } //渲染 this.render = function() { ctx.globalCompositeOperation = "lighter"; ctx.save(); ctx.scale(1, 3); for(var i=0; i < particles.length; i++) { particles[i].render(); } ctx.restore(); } } //火焰群 var Fires = function(locationX, locationY) { var span = 15; var speedX = 0; var speedY = 5; var otherScaleY = 0.5; var leftFire = new Fire(locationX - span, locationY, speedX, speedY * otherScaleY); var middleFire = new Fire(locationX, locationY, speedX, speedY); var rightFire = new Fire(locationX + span, locationY, speedX, speedY * otherScaleY); //更新 function update() { leftFire.update(); middleFire.update(); rightFire.update(); } //渲染 function render() { leftFire.render(); middleFire.render(); rightFire.render(); } this.init = function() { function loop() { clearCanvas(); update(); render(); requestAnimationFrame(loop); } loop(); } } this.init = function() { var location = { x: c.width / 2, y: c.height / 6 + 35, }; var fires = new Fires(location.x, location.y); setupRAF(); fires.init(); } } new CanvasController().init(); </script>
        </body>
    </html>

![这里写图片描述][20170111144242478]

[20170111144242478]: /images/20220713/352c1d2bbd284b8185a98a37f356f7e4.png