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/****************************************************************************
**
** Copyright (C) 2014 Klaralvdalens Datakonsult AB (KDAB).
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt3D module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qtickclock_p.h"
#include <QtCore/QThread>
#include <Qt3DCore/private/corelogging_p.h>
QT_BEGIN_NAMESPACE
namespace Qt3DCore {
QTickClock::QTickClock()
: m_tickInterval(1000000000 / 60) // Nanoseconds
, m_time(0)
{
}
void QTickClock::setTickFrequency(float frequency)
{
Q_ASSERT(frequency > 0.0f);
m_tickInterval = static_cast<qint64>(1000000000 / frequency);
}
void QTickClock::start()
{
m_timer.start();
m_time = m_timer.nsecsElapsed();
qCDebug(ChangeArbiter) << "tickInterval =" << m_tickInterval << "ns";
}
void QTickClock::reset()
{
m_time = 0;
}
qint64 QTickClock::waitForNextTick()
{
qint64 t = m_timer.nsecsElapsed();
qint64 dt = t - m_time;
qint64 timeToSleep = m_tickInterval - dt;
// If we are lagging behind don't delay
// TODO: Do we want a mode where if we are lagging we instead wait
// for the next tick instead?
if (timeToSleep < 0) {
qCDebug(ChangeArbiter) << "Lagging behind desired tick interval";
m_time = t;
return m_time;
}
unsigned long sleepTimeMicroSeconds = static_cast<unsigned long>(timeToSleep / 1000);
//qCDebug(ChangeArbiter) << "sleeping for" << sleepTimeMicroSeconds << "us";
QThread::usleep(sleepTimeMicroSeconds);
#if defined(QT3DCORE_DEBUG_TICKCLOCK)
qint64 expectedWakeTime = t + sleepTimeMicroSeconds * 1000;
qint64 wakeTime = m_timer.nsecsElapsed();
qCDebug(ChangeArbiter) << "t =" << t / 1000000 << "timeToSleep =" << timeToSleep / 1000000
<< "due to wake at =" << expectedWakeTime / 1000000
<< "actually woke at" << wakeTime / 1000000
<< "delta =" << (expectedWakeTime - wakeTime) / 1000000;
#endif
m_time = m_timer.nsecsElapsed();
return m_time;
}
} // namespace Qt3DCore
QT_END_NAMESPACE
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