eng_view_fps.hh

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/*
 * LEGAL:   COPYRIGHT (C) 2007 JIM E. BROOKS
 *          THIS SOURCE CODE IS RELEASED UNDER THE TERMS
 *          OF THE GNU GENERAL PUBLIC LICENSE VERSION 2 (GPL 2).
 *****************************************************************************/

#if ENG_VIEW_CC  // only eng_view.cc needs this
#ifndef ENG_VIEW_FPS_HH
#define ENG_VIEW_FPS_HH 1

namespace eng {

class FPS
{
friend class TimerFunctor;
private:
    class TimerFunctor : public Timer::Functor  // derived from Shared
    {
    public:
                TimerFunctor( FPS& fps ) : mFPS(fps), mSeconds(0) { }
        void    operator()(const Milliseconds millisecElapsed)
        {
            mSeconds = mSeconds + Seconds(1);
            mFPS.CalcFPS();
#if 0
            if ( (int(mSeconds) % 5) == 0 )
            {
                COUT << "FPS = " << mFPS.GetFPS() << endl;
            }
#endif
        }
    public:
        FPS&    mFPS;
        Seconds mSeconds;
    };

public:
    FPS( void )
    :   mFrameCnt(View::INVALID_FRAME_CNT),
        mFrameCntPrev(View::INVALID_FRAME_CNT),
        mFPS(0)
    {
        // Register callback to be called every second which calls CalcFPS().
        shptr<Timer::Functor> functor = new TimerFunctor( *this );  // emphasizing a SharedPtr
        Timer::GetInstance().Register( functor, Milliseconds(Seconds(1)) );
    }

    ~FPS() { }

    void IncFrameCnt( void )
    {
        ++mFrameCnt;
    }

    uint GetFPS( void )
    {
        return mFPS;
    }

private:
    void CalcFPS( void )
    {
        // Delta requires starting and ending frame counts.
        if ( mFrameCntPrev != View::INVALID_FRAME_CNT )
        {
            mFPS = mFrameCnt - mFrameCntPrev;
        }
        mFrameCntPrev = mFrameCnt;
    }

private:
    uint    mFrameCnt;      
    uint    mFrameCntPrev;  
    uint    mFPS;           
};

} // namespace eng

#endif // ENG_VIEW_HH
#endif // ENG_VIEW_CC

Palomino 3D Engine documents generated by doxygen 1.5.3 on Fri Nov 23 11:26:09 2007