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3** Copyright (C) 2015 Paul Lemire
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39
40#include "vsyncframeadvanceservice_p.h"
41#include <Qt3DRender/private/renderlogging_p.h>
42#include <Qt3DCore/private/qabstractframeadvanceservice_p.h>
43#include <Qt3DCore/private/qabstractframeadvanceservice_p_p.h>
44#include <QSemaphore>
45#include <QElapsedTimer>
46
47QT_BEGIN_NAMESPACE
48
49namespace Qt3DRender {
50namespace Render {
51
52class VSyncFrameAdvanceServicePrivate final : public Qt3DCore::QAbstractFrameAdvanceServicePrivate
53{
54public:
55 explicit VSyncFrameAdvanceServicePrivate(bool drivenByRenderThread)
56 : QAbstractFrameAdvanceServicePrivate(QStringLiteral("Renderer Aspect Frame Advance Service - aligned with vsync"))
57 , m_semaphore(0)
58 , m_elapsedTimeSincePreviousFrame(0)
59 , m_drivenByRenderThread(drivenByRenderThread)
60 {
61 }
62
63 QSemaphore m_semaphore;
64 QElapsedTimer m_elapsed;
65 qint64 m_elapsedTimeSincePreviousFrame;
66 bool m_drivenByRenderThread;
67};
68
69VSyncFrameAdvanceService::VSyncFrameAdvanceService(bool drivenByRenderThread)
70 : QAbstractFrameAdvanceService(*new VSyncFrameAdvanceServicePrivate(drivenByRenderThread))
71{
72}
73
74VSyncFrameAdvanceService::~VSyncFrameAdvanceService()
75{
76}
77
78// Main Thread
79qint64 VSyncFrameAdvanceService::waitForNextFrame()
80{
81 Q_D(VSyncFrameAdvanceService);
82
83 d->m_semaphore.acquire(n: std::max(a: d->m_semaphore.available(), b: 1));
84
85 const qint64 currentTime = d->m_elapsed.nsecsElapsed();
86 qCDebug(VSyncAdvanceService) << "Elapsed nsecs since last call " << currentTime - d->m_elapsedTimeSincePreviousFrame;
87 d->m_elapsedTimeSincePreviousFrame = currentTime;
88 return currentTime;
89}
90
91void VSyncFrameAdvanceService::start()
92{
93 Q_D(VSyncFrameAdvanceService);
94 d->m_elapsed.start();
95}
96
97/*!
98 \internal
99
100 Stops the VSyncFrameAdvanceService, releases the semaphore to allow the
101 renderer to cleanup without having to call waitForNextFrame.
102 */
103void VSyncFrameAdvanceService::stop()
104{
105 Q_D(VSyncFrameAdvanceService);
106 d->m_semaphore.release(n: 1);
107 qCDebug(VSyncAdvanceService) << "Terminating VSyncFrameAdvanceService";
108}
109
110// Render Thread
111void VSyncFrameAdvanceService::proceedToNextFrame()
112{
113 Q_D(VSyncFrameAdvanceService);
114 d->m_semaphore.release(n: 1);
115}
116
117} // namespace Render
118} // namespace Qt3DRender
119
120QT_END_NAMESPACE
121

source code of qt3d/src/render/services/vsyncframeadvanceservice.cpp