1 /*

     2  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)

     3  *

     4  * All rights reserved.

     5  *

     6  * Redistribution and use in source and binary forms, with or without

     7  * modification, are permitted provided that the following conditions

     8  * are met:

     9  * 1. Redistributions of source code must retain the above copyright

    10  *    notice, this list of conditions and the following disclaimer.

    11  * 2. Redistributions in binary form must reproduce the above copyright

    12  *    notice, this list of conditions and the following disclaimer in the

    13  *    documentation and/or other materials provided with the distribution.

    14  *

    15  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY

    16  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

    17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

    18  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR

    19  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

    20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

    21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

    22  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

    23  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

    24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

    25  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    26  */

    27 

    28 #include "fpstimer.h"

    29 

    30 #include <QDateTime>

    31 #include <QTimerEvent>

    32 

    33 // We save a maximum of 10000 frames, and purge 2000 at a time

    34 #define MAX_FRAMES_SAVED 10000

    35 #define FRAMES_TO_PURGE_WHEN_FULL 2000

    36 // 60 FPS

    37 #define FPS_MEASURE_INTERVAL 1000 / 60

    38 

    39 FpsTimer::FpsTimer(QObject* parent)

    40         : QObject(parent)

    41 {

    42 }

    43 

    44 int FpsTimer::numFrames(int spanMillis)

    45 {

    46     const QTime now = QTime::currentTime();

    47 

    48     int count = 0;

    49     for (int i = m_frames.length() - 1; i >= 0; --i, ++count) {

    50         int msecs = m_frames[i].msecsTo(now);

    51         if (msecs < 0)

    52             msecs += 24 * 60 * 60 * 1000;

    53         if (msecs > spanMillis)

    54             break;

    55     }

    56     return count;

    57 }

    58 

    59 void FpsTimer::start()

    60 {

    61     m_timer = startTimer(FPS_MEASURE_INTERVAL);

    62 }

    63 

    64 void FpsTimer::stop()

    65 {

    66     killTimer(m_timer);

    67     m_frames.clear();

    68 }

    69 

    70 void FpsTimer::timerEvent(QTimerEvent* event)

    71 {

    72     if (event->timerId() !=  m_timer)

    73         return;

    74     m_frames.append(QTime::currentTime());

    75     if (m_frames.length() > MAX_FRAMES_SAVED)

    76         m_frames.erase(m_frames.begin(), m_frames.begin() + FRAMES_TO_PURGE_WHEN_FULL);

    77 }