laTimer.cpp

/*

Jump'n'Run Engine
http://www.atanaslaskov.com/jnr/

BSD LICENSE
Copyright (c) 2007-2013, Atanas Laskov
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL ATANAS LASKOV BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*/

//
// FILE: laTimer.cpp
// This class facilitates per-frame timing (delta, fps, etc)
//
// Copyright (C) 2007-2013 Atanas Laskov, <latanas@gmail.com>
//

#include "stdafx.h"
#include "jnr.h"

double laTimer::_dTimeMultiplier = 1;   // NOTE: Replace this to enforce some delta and slow down / speed up for debugging

laTimer::laTimer(void)
{
    _dwTickCount = GetTickCount();
    QueryPerformanceFrequency(&fr);

    _ttSampleFPS.parameters(1);
    _ttSampleFPS.enable(M_TRUE);

    _bFirstFrame = M_TRUE;
    _bStatisticsOn = M_FALSE;

    _dFPS = _dFPS_Min = _dFPS_Max = 60;
    _dSPF = 1/_dFPS;
    _dFPS_Sampled = _dFPS_Avg = _dFPS;
    _nsamples = 1;
}

laTimer::~laTimer(void)
{
}

void laTimer::frameForce(double fps)
{
    _dFPS = fps;
    _dSPF = 1/_dFPS;
}

void laTimer::frameStart()
{
    QueryPerformanceCounter(&f_start);
}

// Update timer
// NOTE: This is called only 1-ce per frame, and even if there are some additinal timers,
// it's probably not perfromance critical
//
//
void laTimer::frameEnd()
{
    LARGE_INTEGER f_end;
    QueryPerformanceCounter(&f_end);

    double delta = (f_end.QuadPart - f_start.QuadPart)/((double)fr.QuadPart);

    if( _bFirstFrame )  _bFirstFrame = M_FALSE;
    else {

        _dSPF = delta * _dTimeMultiplier;           // NOTE: Replace this to enforce some delta and slow down / speed up for debugging
        _dFPS = (1.0/_dSPF) * _dTimeMultiplier; // NOTE: Comment multipler for FPS equivalence; Uncomment for real FPS

        if( _bStatisticsOn ) {
            if( _dFPS < _dFPS_Min) _dFPS_Min = _dFPS;
            if( _dFPS > _dFPS_Max) _dFPS_Max = _dFPS;

            _dFPS_Avg = ( _dFPS_Avg * _nsamples + _dFPS ) / ( _nsamples + 1.0 );
            _nsamples += 1;
        }

    }

    _ttSampleFPS.animate(*this);
    if(_ttSampleFPS.isElapsed() /*&& _bStatisticsOn*/ )
    {
        _dFPS_Sampled = _dFPS;
        _ttSampleFPS.reset();
    }
}

void laTimer::statistics_log()
{
    MLOG("FPS Statistics: min( %.1lf FPS ), max( %.1lf FPS ), avg( %.1lf FPS, %.1lf samples )",
        fps_min(), fps_max(), fps_avg(), _nsamples);
}