55 lines
1.5 KiB
Dart
55 lines
1.5 KiB
Dart
// ignore_for_file: avoid_print, prefer_typing_uninitialized_variables
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import 'dart:ui';
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class Frame {
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static var orginalCallback;
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static init() {
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orginalCallback = window.onReportTimings;
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window.onReportTimings = onReportTimings;
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}
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// 仅缓存最近 25 帧绘制耗时
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static const maxframes = 25;
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static final List<FrameTiming> lastFrames = [];
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// 基准 VSync 信号周期
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static const frameInterval =
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Duration(microseconds: Duration.microsecondsPerSecond ~/ 60);
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static void onReportTimings(List<FrameTiming> timings) {
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lastFrames.addAll(timings);
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// 仅保留 25 帧
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if (lastFrames.length > maxframes) {
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lastFrames.removeRange(0, lastFrames.length - maxframes);
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}
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// 如果有原始帧回调函数，则执行
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if (orginalCallback != null) {
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orginalCallback(timings);
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}
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print("fps: $fps");
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}
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static double get fps {
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int sum = 0;
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for (FrameTiming timing in lastFrames) {
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// 计算渲染耗时
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int duration = timing.timestampInMicroseconds(FramePhase.rasterFinish) -
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timing.timestampInMicroseconds(FramePhase.buildStart);
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// 判断耗时是否在 Vsync 信号周期内
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if (duration < frameInterval.inMicroseconds) {
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sum += 1;
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} else {
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// 有丢帧，向上取整
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int count = (duration / frameInterval.inMicroseconds).ceil();
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sum += count;
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}
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}
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return lastFrames.length / sum * 60;
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}
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static destroy() {
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window.onReportTimings = null;
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}
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}
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