AS3 - 距离下一帧/屏幕绘制还有多长时间

发布于 2025-01-04 22:35:05 字数 140 浏览 1 评论 0原文

我有一个生成艺术应用程序，我希望它在每帧中绘制尽可能多的周期而不降低帧速率。有没有办法知道屏幕更新/刷新还剩多少时间？

我想如果我可以估计每个周期需要多少毫秒，那么我可以运行周期直到剩余时间少于平均或峰值周期时间，然后让屏幕刷新，然后运行另一组周期。

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幸福还没到 2025-01-11 22:35:05

如果您希望您的应用程序以每秒 N 帧的速度运行，那么您可以循环绘制 1/N 秒*，其中 N 通常是阶段帧速率（您可以获取和设置）：

import flash.utils.getTimer;
import flash.events.Event;

private var _time_per_frame:uint;

...构造函数：

stage.frameRate = 30;
_time_per_frame = 1000 / stage.frameRate;
addEventListener(Event.ENTER_FRAME, handle_enter_frame);

...

private function handle_enter_frame(e:Event):void
{
  var t0:uint = getTimer();

  while (getTimer()-t0 < _time_per_frame) {
    // ... draw some stuff
  }
}

请注意，这在某种程度上是一种简化，并且可能会导致生成的帧速率比 stage.frameRate 指定的慢，因为 Flash 需要一些时间来在帧之间执行渲染。但是，如果您使用位图传输（在屏幕上绘制位图）而不是在矢量中绘制或将形状添加到屏幕上，那么我认为上面的内容实际上应该非常准确。

如果代码导致帧速率慢于所需的帧速率，您可以尝试一些简单的方法，例如仅花费一帧分配时间的一半，将另一半留给 Flash 渲染：

_time_per_frame = 500 / stage.frameRate;

周围还有 FPS 监视器，您可以使用它们来监视绘图时的帧速率。谷歌 as3 帧率监视器。

If you want your app to run at N frames per second, then you can draw in a loop for 1/N seconds*, where N is typically the stage framerate (which you can get and set):

import flash.utils.getTimer;
import flash.events.Event;

private var _time_per_frame:uint;

... Somewhere in your main constructor:

stage.frameRate = 30;
_time_per_frame = 1000 / stage.frameRate;
addEventListener(Event.ENTER_FRAME, handle_enter_frame);

...

private function handle_enter_frame(e:Event):void
{
  var t0:uint = getTimer();

  while (getTimer()-t0 < _time_per_frame) {
    // ... draw some stuff
  }
}

Note that this is somewhat of a simplification, and may cause a slower resultant framerate than specified by stage.frameRate, because Flash needs some time to perform the rendering in between frames. But if you're blitting (drawing to a Bitmap on screen) as opposed to drawing in vector or adding Shapes to the screen, then I think the above should actually be pretty accurate.

If the code results in slower-than-desired framerates, you could try something as simple as only taking half the allotted time for a frame, leaving the other half for Flash to render:

_time_per_frame = 500 / stage.frameRate;

There are also FPS monitors around that you could use to monitor your framerate while drawing. Google as3 framerate monitor.

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宣告ˉ结束 2025-01-11 22:35:05

将此代码放入主对象并检查 - 它将跟踪每个帧开始之间的时间。

addEventListener(Event.ENTER_FRAME , oef);
var step:Number = 0;
var last:Number = Date.getTime();
function oef(e:Event):void{
    var time:Number = Date.getTime();
    step = time - last;
    last = time;

    trace(step);
}

Put this code to main object and check - it will trace time between each frame start .

addEventListener(Event.ENTER_FRAME , oef);
var step:Number = 0;
var last:Number = Date.getTime();
function oef(e:Event):void{
    var time:Number = Date.getTime();
    step = time - last;
    last = time;

    trace(step);
}

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