计算FPS小例子

uint FPS()
{
    static uint fps = 0;
    /* 从1970-01-01到现在的毫秒数 */
    static uint prevMSecs = QDateTime::currentMSecsSinceEpoch();
    static uint frame = 0;

    frame++;

    uint curMSecs = QDateTime::currentMSecsSinceEpoch();
    /* 计算1秒内的帧数 */
    if (curMSecs - prevMSecs >= 1000) {
        fps = frame;
        frame = 0;
        prevMSecs = curMSecs;
    }

    return fps;
}

for (uint i = 0; i < 1000; i++) {
    qDebug() << FPS();
    QThread::msleep(50);
}