[英]Is there anything faster than setTimeout and requestAnimationFrame?
[英]requestAnimationFrame only when needed runs the animation much faster than having requestAnimationFrame all the time
我试图通过“lerping”跟随鼠标的元素和鼠标位置之间的差异来创建一个“平滑”的动画。
这仅用于演示目的,滚动事件和其他类型的动画也会出现问题。
在原始代码中,一个requestAnimationFrame
“循环”在 JS 加载时开始,并且永不停止。 对我来说,这不是最佳方式,但动画与此方法完美配合。
这是原始演示: https : //codepen.io/ReGGae/pen/NQKENZ?editors=0010
let target = 0
let current = 0
const ease = 0.075
const element = document.querySelector('.js-lerp-me')
window.addEventListener('mousemove', (e) => {
target = e.clientX // Stores the mouse (X) positon
})
function animate() {
current += ((target - current) * ease) // This is where the magic happens
element.style.transform = `translate3d(${current}px, 0, 0)`
requestAnimationFrame(animate)
}
animate() // Runs 60 times per second
(这个例子由 Jesper Landberg 提供给我,以便向我解释 lerping)
在我的代码中,我尝试通过仅在mousemove
事件被触发时运行requestAnimationFrame
"loop" 来优化它,并在它接近完成时停止它(几乎是因为它永远无法完成 lerping)。
我的版本: https : //codepen.io/samuelgozi/pen/QeWzWy?editors=0010
let target = 0
let current = 0
const ease = 0.075
const element = document.querySelector('.js-lerp-me')
// Checks that both numbers are within a range.
// The default range is 1 because the units passed to this are pixels,
// and with lerping the last pixel never really arrives at the target.
function nearlyEqual(a, b, targetDiff = 1) {
return Math.abs(a - b) < targetDiff;
}
window.addEventListener('mousemove', (e) => {
target = e.clientX // Stores the mouse (X) positon
animate()
})
function animate() {
current += ((target - current) * ease)
element.style.transform = `translate3d(${current}px, 0, 0)`
if (nearlyEqual(target, current)) return // If we are close enough to the target, then dont request another animation frame.
requestAnimationFrame(animate)
}
正如您在演示中看到的那样,在我的版本中它运行得更快,并且感觉不那么“轻松”,换句话说,效果丢失了。 即使您降低ease
乘数,它仍然感觉不同。
有人可以向我解释发生了什么吗?
原始只运行一个循环。 我认为这是因为每次发生 mousemove 事件时都会启动一个新动画,然后几个将同时运行,所以我稍微修改了你的代码,只启动一个新动画,直到当前动画循环停止。
let target = 0
let current = 0
let animating = false
const ease = 0.075
const element = document.querySelector('.js-lerp-me')
// Checks that both numbers are within a range.
// The default range is 1 because the units passed to this are pixels,
// and with lerping the last pixel never really arrives at the target.
function nearlyEqual(a, b, targetDiff = 1) {
return Math.abs(a - b) < targetDiff;
}
window.addEventListener('mousemove', (e) => {
target = e.clientX // Stores the mouse (X) positon
if (!animating) {
animate()
animating = true
}
})
function animate() {
current += ((target - current) * ease) // This is where the magic happens
element.style.transform = `translate3d(${current}px, 0, 0)`
if (nearlyEqual(target, current)) {
animating = false
return
}
requestAnimationFrame(animate)
}
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