fps property

double get fps

Implementation

static double get fps {
  int sum = 0;
  for (FrameTiming timing in lastFrames) {
    // 计算渲染耗时
    int duration = timing.timestampInMicroseconds(FramePhase.rasterFinish) -
        timing.timestampInMicroseconds(FramePhase.buildStart);
    // 判断耗时是否在 Vsync 信号周期内
    if (duration < frameInterval.inMicroseconds) {
      sum += 1;
    } else {
      // 有丢帧，向上取整
      int count = (duration / frameInterval.inMicroseconds).ceil();
      sum += count;
    }
  }
  return lastFrames.length / sum * 60;
}