| 1 | // Copyright (C) 2014 Klaralvdalens Datakonsult AB (KDAB). |
|---|---|
| 2 | // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only |
| 3 | |
| 4 | #include "qtickclock_p.h" |
| 5 | |
| 6 | #include <QtCore/QThread> |
| 7 | |
| 8 | #include <Qt3DCore/private/corelogging_p.h> |
| 9 | |
| 10 | QT_BEGIN_NAMESPACE |
| 11 | |
| 12 | namespace Qt3DCore { |
| 13 | |
| 14 | QTickClock::QTickClock() |
| 15 | : m_tickInterval(1000000000 / 60) // Nanoseconds |
| 16 | , m_time(0) |
| 17 | { |
| 18 | } |
| 19 | |
| 20 | void QTickClock::setTickFrequency(float frequency) |
| 21 | { |
| 22 | Q_ASSERT(frequency > 0.0f); |
| 23 | m_tickInterval = static_cast<qint64>(1000000000 / frequency); |
| 24 | } |
| 25 | |
| 26 | void QTickClock::start() |
| 27 | { |
| 28 | m_timer.start(); |
| 29 | m_time = m_timer.nsecsElapsed(); |
| 30 | qCDebug(ChangeArbiter) << "tickInterval ="<< m_tickInterval << "ns"; |
| 31 | } |
| 32 | |
| 33 | void QTickClock::reset() |
| 34 | { |
| 35 | m_time = 0; |
| 36 | } |
| 37 | |
| 38 | qint64 QTickClock::waitForNextTick() |
| 39 | { |
| 40 | qint64 t = m_timer.nsecsElapsed(); |
| 41 | qint64 dt = t - m_time; |
| 42 | qint64 timeToSleep = m_tickInterval - dt; |
| 43 | |
| 44 | // If we are lagging behind don't delay |
| 45 | // TODO: Do we want a mode where if we are lagging we instead wait |
| 46 | // for the next tick instead? |
| 47 | if (timeToSleep < 0) { |
| 48 | qCDebug(ChangeArbiter) << "Lagging behind desired tick interval"; |
| 49 | m_time = t; |
| 50 | return m_time; |
| 51 | } |
| 52 | |
| 53 | unsigned long sleepTimeMicroSeconds = static_cast<unsigned long>(timeToSleep / 1000); |
| 54 | //qCDebug(ChangeArbiter) << "sleeping for" << sleepTimeMicroSeconds << "us"; |
| 55 | QThread::usleep(sleepTimeMicroSeconds); |
| 56 | |
| 57 | #if defined(QT3DCORE_DEBUG_TICKCLOCK) |
| 58 | qint64 expectedWakeTime = t + sleepTimeMicroSeconds * 1000; |
| 59 | qint64 wakeTime = m_timer.nsecsElapsed(); |
| 60 | qCDebug(ChangeArbiter) << "t ="<< t / 1000000 << "timeToSleep ="<< timeToSleep / 1000000 |
| 61 | << "due to wake at ="<< expectedWakeTime / 1000000 |
| 62 | << "actually woke at"<< wakeTime / 1000000 |
| 63 | << "delta ="<< (expectedWakeTime - wakeTime) / 1000000; |
| 64 | #endif |
| 65 | |
| 66 | m_time = m_timer.nsecsElapsed(); |
| 67 | return m_time; |
| 68 | } |
| 69 | |
| 70 | } // namespace Qt3DCore |
| 71 | |
| 72 | QT_END_NAMESPACE |
| 73 |