| 标题 | html5使用canvas实现跟随光标跳动的火焰效果 |
| 范文 | 本效果的完整代码如下,把代码保存到HTML文件中打开也能查看效果,火焰会跟随光标: 代码如下: <!DOCTYPE HTML> <head> <meta charset=utf-8" /> <title>HTML5 Canvas火焰效果</title> <style type="text/css"> body{margin: 0; padding: 0;} #canvas-keleyi-com {display: block;} </style> </head> <body> <canvas id="canvas-keleyi-com"></canvas> <script type="text/javascript"> window.onload = function(){ var keleyi_canvas = document.getElementById("canvas-kel"+"eyi-com"); var ctx = keleyi_canvas.getContext("2d"); var W = window.innerWidth, H = window.innerHeight; keleyi_canvas.width = W; keleyi_canvas.height = H;</p> <p>var particles = []; var mouse = {};</p> <p>//Lets create some particles now var particle_count = 100; for(var i = 0; i < particle_count; i++) { particles.push(new particle()); } keleyi_canvas.addEventListener('mousemove', track_mouse, false);</p> <p>function track_mouse(e) { mouse.x = e.pageX; mouse.y = e.pageY; }</p> <p>function particle() { this.speed = {x: -2.5+Math.random()*5, y: -15+Math.random()*10}; //location = mouse coordinates //Now the flame follows the mouse coordinates if(mouse.x && mouse.y) { this.location = {x: mouse.x, y: mouse.y}; } else { this.location = {x: W/2, y: H/2}; } //radius range = 10-30 this.radius = 10+Math.random()*20; //life range = 20-30 this.life = 20+Math.random()*10; this.remaining_life = this.life; //colors this.r = Math.round(Math.random()*255); this.g = Math.round(Math.random()*255); this.b = Math.round(Math.random()*255); }</p> <p>function draw() { ctx.globalCompositeOperation = "source-over"; ctx.fillStyle = "black"; ctx.fillRect(0, 0, W, H); ctx.globalCompositeOperation = "lighter";</p> <p>for(var i = 0; i < particles.length; i++) { var p = particles[i]; ctx.beginPath(); p.opacity = Math.round(p.remaining_life/p.life*100)/100 var gradient = ctx.createRadialGradient(p.location.x, p.location.y, 0, p.location.x, p.location.y, p.radius); gradient.addColorStop(0, "rgba("+p.r+", "+p.g+", "+p.b+", "+p.opacity+")"); gradient.addColorStop(0.5, "rgba("+p.r+", "+p.g+", "+p.b+", "+p.opacity+")"); gradient.addColorStop(1, "rgba("+p.r+", "+p.g+", "+p.b+", 0)"); ctx.fillStyle = gradient; ctx.arc(p.location.x, p.location.y, p.radius, Math.PI*2, false); ctx.fill();</p> <p> p.remaining_life--; p.radius--; p.location.x += p.speed.x; p.location.y += p.speed.y;</p> <p>if(p.remaining_life < 0 || p.radius < 0) { particles[i] = new particle(); } } }</p> <p>setInterval(draw, 86); } </script> </body> </html> |
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