requestanimationframe

炫彩字and鼠标爱心

阅读更多关于炫彩字and鼠标爱心

<!DOCTYPE html> <style type="text/css"> body{ background-color: black; } #zx { font-weight: 600; font-size: 28px; font-family: "黑体"; color: #8c888b; background: -webkit-linear-gradient(45deg, #70f7fe, #fbd7c6, #fdefac, #bfb5dd, #bed5f5); color: transparent; /*设置字体颜色透明*/ -webkit-background-clip: text; /*背景裁剪为文本形式*/ animation: ran 10s linear infinite; /*动态10s展示*/ } @keyframes ran { from { backgroud-position: 0 0; } to { background-position: 2000px 0; } } </style> <script type="text/javascript"> function changeColor(){ //var color="#f00|#0f0|#00f|#880|#808|#088|#bcc8ed|#|#|#|#234|#534";/

Up to date polyfill for requestAnimationFrame

阅读更多关于 Up to date polyfill for requestAnimationFrame

http://updates.html5rocks.com/2012/05/requestAnimationFrame-API-now-with-sub-millisecond-precision tells me that recently (Chrome 20) requestAnimationFrame has gained a new sub-millisecond precision timer, and that I have to update my code to support it. Looking around at the various polyfills around, they all seem to pre-date this update. Are they somehow functional (I don't think so), or is there simply not an up-to-date one available? Should I just do the timing myself (seems a bit wasteful). I had just read that article too and was curious to try this myself. I've taken a stab at adding a

Up to date polyfill for requestAnimationFrame

阅读更多关于 Up to date polyfill for requestAnimationFrame

问题 http://updates.html5rocks.com/2012/05/requestAnimationFrame-API-now-with-sub-millisecond-precision tells me that recently (Chrome 20) requestAnimationFrame has gained a new sub-millisecond precision timer, and that I have to update my code to support it. Looking around at the various polyfills around, they all seem to pre-date this update. Are they somehow functional (I don't think so), or is there simply not an up-to-date one available? Should I just do the timing myself (seems a bit

使用 window.requestAnimationFrame 实现动画效果

阅读更多关于使用 window.requestAnimationFrame 实现动画效果

1. 简介原生 JavaScript 中，我们可以通过 setTimeout() 或是 setInterval() 来不断更新元素状态以实现动画效果。要看到流畅的动画效果，就需要在更新元素状态时以一定的频率进行，我们先来了解一下“帧”的概念。以下是百度百科是关于“帧”的说明：为了更好地说明帧的概念，我们先来看看电影播放的基本原理。在放映电影的过程中，画面被一幅幅地放映在银幕上。画幅移开时，光线就被遮住，幕上便出现短暂的黑暗；每放映一个画幅后，幕上就黑暗一次。但这一次次极短暂的黑暗，被人的视觉生理现象“视觉暂留”所弥补。人眼在观察景物时，光信号传入大脑神经需经过一段短暂时间，光的作用结束时，视觉也不立即消失。视觉的这一现象称为“视觉暂留”。当电影画面换幅频率达到每秒15幅~30幅时，观众便见不到黑暗的间隔了，这时人“看到”的就是运动的事物，这就是电影的基本原理。这里的一幅画面就是电影的一帧，实际上就是电影胶片中的一格。帧——就是影像动画中最小单位的单幅影像画面。一帧就是一副静止的画面，连续的帧就形成动画，如电视图象等。我们通常说帧数，简单地说，就是在1秒钟时间里传输的图片的帧数，也可以理解为图形处理器每秒钟能够刷新几次，通常用 FPS（Frames Per Second）表示。每一帧都是静止的图象，快速连续地显示帧便形成了运动的假象。高的帧率可以得到更流畅、更逼真的动画

requestAnimationFrame [now] vs performance.now() time discrepancy

阅读更多关于 requestAnimationFrame [now] vs performance.now() time discrepancy

Assumptions: rAF now time is calculated at the time the set of callbacks are all triggered. Therefore any blocking that happens before the first callback of that frame is called doesn't affect the rAF now and it's accurate--at least for that first callback. Any performance.now() measurements made before a rAF set is triggered should be earlier than rAF now . Test: Record before (a baseline time before anything happens). Set the next rAF. Compare rAF now and actual performance.now() to before to see how different they are. Expected results: var before = performance.now(), frames = ["with

Is wanting to control the FPS of my animation a good reason to continue using setTimeout in stead of requestAnimationFrame?

阅读更多关于 Is wanting to control the FPS of my animation a good reason to continue using setTimeout in stead of requestAnimationFrame?

I'm wondering if I should switch my game over to requestAnimationFrame. If there even is still a reason to do so anymore, as I've read that setTimeout() now also pauses when you switch tabs in the major browsers. Anyway, say I want to control the FPS of my animation. Currently I can do it like this: k.state.loopinterval = window.setInterval(renderLoop(), 1000 / k.settings.engine.fps ); Where k.settings.engine.fps is the wanted fps. If I do it the requestAnimationFrame way, I lose that possibility, and it'll just give me whatever it can give: window.requestAnimFrame(k.operations.startLoop);

Call a function each x second in requestAnimationFrame

阅读更多关于 Call a function each x second in requestAnimationFrame

问题 I'm working on some personal project by Three.js. I'm using requestAnimationFrame function. I want to call a function each 2 seconds. I've search but I couldn't find anything useful. My code is like this: function render() { // each 2 seconds call the createNewObject() function if(eachTwoSecond) { createNewObject(); } requestAnimationFrame(render); renderer.render(scene, camera); } Any Idea? 回答1: requestAnimationFrame passes single parameter to your callback which indicates the current time

Adding additional arguments to a function called back by requestAnimationFrame

阅读更多关于 Adding additional arguments to a function called back by requestAnimationFrame

问题 I am looking to create a function that scrolls an image element x pixels over y time on an HTML5 canvas, using requestAnimationFrame and delta time. What I can't figure out is how to add more arguments to my function, when requestAnimationFrame allready calls back my function with one argument (a DOMHighResTimeStamp). I am pretty sure the following code doesn't work: function scroll(timestamp, distanceToScroll, secondsToScroll) { //delta = how many milliseconds have passed between this and

Is wanting to control the FPS of my animation a good reason to continue using setTimeout in stead of requestAnimationFrame?

阅读更多关于 Is wanting to control the FPS of my animation a good reason to continue using setTimeout in stead of requestAnimationFrame?

问题 I'm wondering if I should switch my game over to requestAnimationFrame. If there even is still a reason to do so anymore, as I've read that setTimeout() now also pauses when you switch tabs in the major browsers. Anyway, say I want to control the FPS of my animation. Currently I can do it like this: k.state.loopinterval = window.setInterval(renderLoop(), 1000 / k.settings.engine.fps ); Where k.settings.engine.fps is the wanted fps. If I do it the requestAnimationFrame way, I lose that

阅读更多关于 requestAnimationFrame

window.requestAnimationFrame() 告诉浏览器——你希望执行一个动画，并且要求浏览器在下次重绘之前调用指定的回调函数更新动画。该方法需要传入一个回调函数作为参数，该回调函数会在浏览器下一次重绘之前执行 requestAnimationFrame，顾名思义就是请求动画帧。屏幕刷新频率一般为60Hzs seTimeout实现动画：利用seTimeout实现的动画在某些低端机上会出现卡顿、抖动的现象　　原因一、setTimeout的执行时间并不是确定的。在Javascript中， setTimeout 任务被放进了异步队列中，只有当主线程上的任务执行完以后，才会去检查该队列里的任务是否需要开始执行，因此 setTimeout 的实际执行时间一般要比其设定的时间晚一些。　　原因二、刷新频率受屏幕分辨率和屏幕尺寸的影响，因此不同设备的屏幕刷新频率可能会不同，而 setTimeout只能设置一个固定的时间间隔，这个时间不一定和屏幕的刷新时间相同。　　上两种情况都会导致setTimeout的执行步调和屏幕的刷新步调不一致，从而引起丢帧现象。 setTimeout的执行只是在内存中对图像属性进行改变，这个变化必须要等到屏幕下次刷新时才会被更新到屏幕上。如果两者的步调不一致，就可能会导致中间某一帧的操作被跨越过去，而直接更新下一帧的图像。

订阅 requestanimationframe