统计帧率的几种方法

class CFpsSta
{public:
    time_t m_start_time;
    bool flag;
    float m_count;
    float m_last_fps;
    CFpsSta();
    void checkFps();
};

void CFpsSta::checkFps()
{
    time_t current_time=time(NULL);
    double diff=difftime(current_time,m_start_time);
    
    if (diff>=5 && !flag)
    {
        m_last_fps=m_count/diff;
        cout<<m_last_fps<<endl;
        flag=true;
        m_start_time=current_time;
        m_count=0;
    }
    if ( flag)
    {
        flag=false;
    }

    
}

每5秒计算一次平均帧率，并清空数值，重新计数；下一次调用时，重设flag；  其中m_count在绘制函数后++。

class CFpsSta2
{public:

queue<time_t> counts;

CFpsSta2();
void checkFps();
};

void CFpsSta2::checkFps()
{
    time_t current_time=time(NULL);
    counts.push(current_time);

    double diff=current_time-counts.front();
    //cout<<diff<<endl;
    if(diff>=1)
    {
        cout<<counts.size()/diff<<endl;
        while(!counts.empty())
            counts.pop();    
    }
}