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
FpsTimer(QObject * parent)39 FpsTimer::FpsTimer(QObject* parent)
40 : QObject(parent)
41 , m_timer(0)
42 {
43 }
44
numFrames(int spanMillis) const45 int FpsTimer::numFrames(int spanMillis) const
46 {
47 const QTime now = QTime::currentTime();
48
49 int count = 0;
50 for (int i = m_frames.length() - 1; i >= 0; --i, ++count) {
51 int msecs = m_frames[i].msecsTo(now);
52 if (msecs < 0)
53 msecs += 24 * 60 * 60 * 1000;
54 if (msecs > spanMillis)
55 break;
56 }
57 return count;
58 }
59
start()60 void FpsTimer::start()
61 {
62 m_timer = startTimer(FPS_MEASURE_INTERVAL);
63 }
64
stop()65 void FpsTimer::stop()
66 {
67 if (!m_timer)
68 return;
69 killTimer(m_timer);
70 m_frames.clear();
71 }
72
timerEvent(QTimerEvent * event)73 void FpsTimer::timerEvent(QTimerEvent* event)
74 {
75 if (event->timerId() != m_timer)
76 return;
77 m_frames.append(QTime::currentTime());
78 if (m_frames.length() > MAX_FRAMES_SAVED)
79 m_frames.erase(m_frames.begin(), m_frames.begin() + FRAMES_TO_PURGE_WHEN_FULL);
80 }
81