Merge remote-tracking branch 'qt-gerrit/wip/refactor' into HEAD

Change-Id: Id73bbecd18edaf46ba481aa018e837a336860223

22 files changed, 421 insertions, 455 deletions

diff --git a/src/core/aspects/aspects.pri b/src/core/aspects/aspects.pri
index ced33f310..5e8327192 100644
--- a/src/core/aspects/aspects.pri
+++ b/src/core/aspects/aspects.pri
@@ -4,8 +4,7 @@ SOURCES += \
         $$PWD/qabstractaspect.cpp \
         $$PWD/qaspectengine.cpp \
         $$PWD/qaspectfactory.cpp \
-        $$PWD/qaspectmanager.cpp \
-        $$PWD/qaspectthread.cpp
+        $$PWD/qaspectmanager.cpp
 
 HEADERS += \
         $$PWD/qabstractaspect.h \
@@ -13,8 +12,7 @@ HEADERS += \
         $$PWD/qabstractaspect_p.h \
         $$PWD/qaspectengine_p.h \
         $$PWD/qaspectfactory_p.h \
-        $$PWD/qaspectmanager_p.h \
-        $$PWD/qaspectthread_p.h
+        $$PWD/qaspectmanager_p.h
 
 INCLUDEPATH += $$PWD
 
diff --git a/src/core/aspects/qabstractaspect.cpp b/src/core/aspects/qabstractaspect.cpp
index 7b08dec81..7636fd666 100644
--- a/src/core/aspects/qabstractaspect.cpp
+++ b/src/core/aspects/qabstractaspect.cpp
@@ -40,6 +40,9 @@
 #include "qabstractaspect.h"
 #include "qabstractaspect_p.h"
 
+#include <QMetaObject>
+#include <QMetaProperty>
+
 #include <Qt3DCore/qentity.h>
 #include <Qt3DCore/qpropertyupdatedchange.h>
 
@@ -48,6 +51,7 @@
 #include <Qt3DCore/private/qaspectmanager_p.h>
 #include <Qt3DCore/private/qchangearbiter_p.h>
 #include <Qt3DCore/private/qnodevisitor_p.h>
+#include <Qt3DCore/private/qnode_p.h>
 #include <Qt3DCore/private/qscene_p.h>
 
 QT_BEGIN_NAMESPACE
@@ -170,7 +174,14 @@ QNodeId QAbstractAspect::rootEntityId() const Q_DECL_NOEXCEPT
 void QAbstractAspect::registerBackendType(const QMetaObject &obj, const QBackendNodeMapperPtr &functor)
 {
     Q_D(QAbstractAspect);
-    d->m_backendCreatorFunctors.insert(&obj, functor);
+    d->m_backendCreatorFunctors.insert(&obj, {functor, QAbstractAspectPrivate::DefaultMapper});
+}
+
+void QAbstractAspect::registerBackendType(const QMetaObject &obj, const QBackendNodeMapperPtr &functor, bool supportsSyncing)
+{
+    Q_D(QAbstractAspect);
+    const auto f = supportsSyncing ? QAbstractAspectPrivate::SupportsSyncing : QAbstractAspectPrivate::DefaultMapper;
+    d->m_backendCreatorFunctors.insert(&obj, {functor, f});
 }
 
 void QAbstractAspect::unregisterBackendType(const QMetaObject &obj)
@@ -203,12 +214,96 @@ QVector<QAspectJobPtr> QAbstractAspect::jobsToExecute(qint64 time)
     return QVector<QAspectJobPtr>();
 }
 
+void QAbstractAspect::syncDirtyFrontEndNodes(const QVector<QNode *> &nodes)
+{
+    Q_D(QAbstractAspect);
+    d->syncDirtyFrontEndNodes(nodes);
+}
+
+void QAbstractAspectPrivate::syncDirtyFrontEndNodes(const QVector<QNode *> &nodes)
+{
+    for (auto node: qAsConst(nodes)) {
+        const QMetaObject *metaObj = node->metaObject();
+        QBackendNodeMapperPtr backendNodeMapper;
+        bool supportsSyncing = false;
+        while (metaObj != nullptr && backendNodeMapper.isNull()) {
+            auto v = m_backendCreatorFunctors.value(metaObj);
+            backendNodeMapper = v.first;
+            supportsSyncing = v.second & SupportsSyncing;
+            metaObj = metaObj->superClass();
+        }
+
+        if (!backendNodeMapper)
+            continue;
+
+        QBackendNode *backend = backendNodeMapper->get(node->id());
+        if (!backend)
+            continue;
+        if (supportsSyncing)
+            syncDirtyFrontEndNode(node, backend, false);
+        else
+            sendPropertyMessages(node, backend);
+    }
+}
+
+void QAbstractAspectPrivate::syncDirtyFrontEndNode(QNode *node, QBackendNode *backend, bool firstTime) const
+{
+    Q_UNUSED(firstTime);
+    Q_ASSERT(false); // overload in derived class
+    sendPropertyMessages(node, backend);
+}
+
+void QAbstractAspectPrivate::sendPropertyMessages(QNode *node, QBackendNode *backend) const
+{
+    const int offset = QNode::staticMetaObject.propertyOffset();
+    const auto metaObj = node->metaObject();
+    const int count = metaObj->propertyCount();
+
+    const auto toBackendValue = [](const QVariant &data) -> QVariant
+    {
+        if (data.canConvert<QNode*>()) {
+            QNode *node = data.value<QNode*>();
+
+            // Ensure the node and all ancestors have issued their node creation changes.
+            // We can end up here if a newly created node with a parent is immediately set
+            // as a property on another node. In this case the deferred call to
+            // _q_postConstructorInit() will not have happened yet as the event
+            // loop will still be blocked. We need to do this for all ancestors,
+            // since the subtree of this node otherwise can end up on the backend
+            // with a reference to a non-existent parent.
+            if (node)
+                QNodePrivate::get(node)->_q_ensureBackendNodeCreated();
+
+            const QNodeId id = node ? node->id() : QNodeId();
+            return QVariant::fromValue(id);
+        }
+
+        return data;
+    };
+
+    QPropertyUpdatedChange change(node->id());
+    QPropertyUpdatedChangePtr pchange(&change, [](QPropertyUpdatedChange *) { });
+    for (int index = offset; index < count; index++) {
+        const QMetaProperty pro = metaObj->property(index);
+        change.setPropertyName(pro.name());
+        change.setValue(toBackendValue(pro.read(node)));
+        backend->sceneChangeEvent(pchange);
+    }
+
+    auto const dynamicProperties = node->dynamicPropertyNames();
+    for (const QByteArray &name: dynamicProperties) {
+        change.setPropertyName(name.data());
+        change.setValue(toBackendValue(node->property(name.data())));
+        backend->sceneChangeEvent(pchange);
+    }
+}
+
 QBackendNode *QAbstractAspectPrivate::createBackendNode(const QNodeCreatedChangeBasePtr &change) const
 {
     const QMetaObject *metaObj = change->metaObject();
     QBackendNodeMapperPtr backendNodeMapper;
     while (metaObj != nullptr && backendNodeMapper.isNull()) {
-        backendNodeMapper = m_backendCreatorFunctors.value(metaObj);
+        backendNodeMapper = m_backendCreatorFunctors.value(metaObj).first;
         metaObj = metaObj->superClass();
     }
 
@@ -248,6 +343,7 @@ QBackendNode *QAbstractAspectPrivate::createBackendNode(const QNodeCreatedChange
     return backend;
 }
 
+
 void QAbstractAspectPrivate::clearBackendNode(const QNodeDestroyedChangePtr &change) const
 {
     // Each QNodeDestroyedChange may contain info about a whole sub-tree of nodes that
@@ -259,7 +355,7 @@ void QAbstractAspectPrivate::clearBackendNode(const QNodeDestroyedChangePtr &cha
 
         // Find backend node mapper for this type
         while (metaObj != nullptr && backendNodeMapper.isNull()) {
-            backendNodeMapper = m_backendCreatorFunctors.value(metaObj);
+            backendNodeMapper = m_backendCreatorFunctors.value(metaObj).first;
             metaObj = metaObj->superClass();
         }
 
diff --git a/src/core/aspects/qabstractaspect.h b/src/core/aspects/qabstractaspect.h
index 1ae85e4e6..a9f4f03fc 100644
--- a/src/core/aspects/qabstractaspect.h
+++ b/src/core/aspects/qabstractaspect.h
@@ -77,12 +77,17 @@ protected:
 
     template<class Frontend>
     void registerBackendType(const QBackendNodeMapperPtr &functor);
-    void registerBackendType(const QMetaObject &, const QBackendNodeMapperPtr &functor);
+    template<class Frontend, bool supportsSyncing>
+    void registerBackendType(const QBackendNodeMapperPtr &functor);
+    void registerBackendType(const QMetaObject &obj, const QBackendNodeMapperPtr &functor);
     template<class Frontend>
     void unregisterBackendType();
     void unregisterBackendType(const QMetaObject &);
 
 private:
+    void syncDirtyFrontEndNodes(const QVector<QNode *> &nodes);
+    void registerBackendType(const QMetaObject &obj, const QBackendNodeMapperPtr &functor, bool supportsSyncing);
+
     virtual QVariant executeCommand(const QStringList &args);
 
     virtual QVector<QAspectJobPtr> jobsToExecute(qint64 time);
@@ -104,6 +109,12 @@ void QAbstractAspect::registerBackendType(const QBackendNodeMapperPtr &functor)
     registerBackendType(Frontend::staticMetaObject, functor);
 }
 
+template<class Frontend, bool supportsSyncing>
+void QAbstractAspect::registerBackendType(const QBackendNodeMapperPtr &functor)
+{
+    registerBackendType(Frontend::staticMetaObject, functor, supportsSyncing);
+}
+
 template<class Frontend>
 void QAbstractAspect::unregisterBackendType()
 {
diff --git a/src/core/aspects/qabstractaspect_p.h b/src/core/aspects/qabstractaspect_p.h
index e743dc63a..668b9670c 100644
--- a/src/core/aspects/qabstractaspect_p.h
+++ b/src/core/aspects/qabstractaspect_p.h
@@ -121,6 +121,9 @@ public:
 
     QBackendNode *createBackendNode(const QNodeCreatedChangeBasePtr &change) const override;
     void clearBackendNode(const QNodeDestroyedChangePtr &change) const;
+    void syncDirtyFrontEndNodes(const QVector<QNode *> &nodes);
+    virtual void syncDirtyFrontEndNode(QNode *node, QBackendNode *backend, bool firstTime) const;
+    void sendPropertyMessages(QNode *node, QBackendNode *backend) const;
 
     void sceneNodeAdded(Qt3DCore::QSceneChangePtr &e) override;
     void sceneNodeRemoved(Qt3DCore::QSceneChangePtr &e) override;
@@ -134,12 +137,17 @@ public:
 
     Q_DECLARE_PUBLIC(QAbstractAspect)
 
+    enum NodeMapperInfo {
+        DefaultMapper = 0,
+        SupportsSyncing = 1 << 0
+    };
+
     QEntity *m_root;
     QNodeId m_rootId;
     QAspectManager *m_aspectManager;
     QAbstractAspectJobManager *m_jobManager;
     QChangeArbiter *m_arbiter;
-    QHash<const QMetaObject*, QBackendNodeMapperPtr> m_backendCreatorFunctors;
+    QHash<const QMetaObject*, QPair<QBackendNodeMapperPtr, NodeMapperInfo>> m_backendCreatorFunctors;
     QMutex m_singleShotMutex;
     QVector<QAspectJobPtr> m_singleShotJobs;
 
diff --git a/src/core/aspects/qaspectengine.cpp b/src/core/aspects/qaspectengine.cpp
index 222c4c2af..c5e4b2b26 100644
--- a/src/core/aspects/qaspectengine.cpp
+++ b/src/core/aspects/qaspectengine.cpp
@@ -47,7 +47,6 @@
 #include <QtCore/QMetaObject>
 
 #include <Qt3DCore/private/corelogging_p.h>
-#include <Qt3DCore/private/qaspectthread_p.h>
 #include <Qt3DCore/private/qaspectmanager_p.h>
 #include <Qt3DCore/private/qchangearbiter_p.h>
 #include <Qt3DCore/private/qeventfilterservice_p.h>
@@ -74,9 +73,11 @@ QAspectEnginePrivate *QAspectEnginePrivate::get(QAspectEngine *q)
 
 QAspectEnginePrivate::QAspectEnginePrivate()
     : QObjectPrivate()
+    , m_aspectManager(nullptr)
     , m_postman(nullptr)
     , m_scene(nullptr)
     , m_initialized(false)
+    , m_runMode(QAspectEngine::Automatic)
     #if QT_CONFIG(qt3d_profile_jobs)
     , m_commandDebugger(new Debug::AspectCommandDebugger(q_func()))
     #endif
@@ -119,12 +120,6 @@ void QAspectEnginePrivate::initEntity(QEntity *entity)
     }
 }
 
-void QAspectEnginePrivate::generateCreationChanges(QNode *root)
-{
-    const QNodeCreatedChangeGenerator generator(root);
-    m_creationChanges = generator.creationChanges();
-}
-
 /*!
  * \class Qt3DCore::QAspectEngine
  * \inheaderfile Qt3DCore/QAspectEngine
@@ -185,8 +180,7 @@ QAspectEngine::QAspectEngine(QObject *parent)
     d->m_scene = new QScene(this);
     d->m_postman = new QPostman(this);
     d->m_postman->setScene(d->m_scene);
-    d->m_aspectThread = new QAspectThread(this);
-    d->m_aspectThread->waitForStart(QThread::HighestPriority);
+    d->m_aspectManager = new QAspectManager(this);
 }
 
 /*!
@@ -206,11 +200,6 @@ QAspectEngine::~QAspectEngine()
     for (auto aspect : aspects)
         unregisterAspect(aspect);
 
-    // Wait for thread to have completed it's final loop of execution
-    d->m_aspectThread->aspectManager()->quit();
-    d->m_aspectThread->wait();
-
-    delete d->m_aspectThread;
     delete d->m_postman;
     delete d->m_scene;
 }
@@ -225,15 +214,12 @@ void QAspectEnginePrivate::initNodeTree(QNode *node)
 
 void QAspectEnginePrivate::initialize()
 {
-    QChangeArbiter *arbiter = m_aspectThread->aspectManager()->changeArbiter();
+    m_aspectManager->initialize();
+    QChangeArbiter *arbiter = m_aspectManager->changeArbiter();
     m_scene->setArbiter(arbiter);
     QChangeArbiter::createUnmanagedThreadLocalChangeQueue(arbiter);
-    QMetaObject::invokeMethod(arbiter,
-                              "setPostman",
-                              Q_ARG(Qt3DCore::QAbstractPostman*, m_postman));
-    QMetaObject::invokeMethod(arbiter,
-                              "setScene",
-                              Q_ARG(Qt3DCore::QScene*, m_scene));
+    arbiter->setPostman(m_postman);
+    arbiter->setScene(m_scene);
     m_initialized = true;
 #if QT_CONFIG(qt3d_profile_jobs)
     m_commandDebugger->setAspectEngine(q_func());
@@ -263,14 +249,14 @@ void QAspectEnginePrivate::shutdown()
 
     // Cleanup the scene before quitting the backend
     m_scene->setArbiter(nullptr);
-    QChangeArbiter *arbiter = m_aspectThread->aspectManager()->changeArbiter();
+    QChangeArbiter *arbiter = m_aspectManager->changeArbiter();
     QChangeArbiter::destroyUnmanagedThreadLocalChangeQueue(arbiter);
     m_initialized = false;
 }
 
 void QAspectEnginePrivate::exitSimulationLoop()
 {
-    m_aspectThread->aspectManager()->exitSimulationLoop();
+    m_aspectManager->exitSimulationLoop();
 }
 
 /*!
@@ -285,12 +271,8 @@ void QAspectEngine::registerAspect(QAbstractAspect *aspect)
     // AspectManager::registerAspect is called in the context
     // of the AspectThread. This is turns call aspect->onInitialize
     // still in the same AspectThread context
-    aspect->moveToThread(d->m_aspectThread);
     d->m_aspects << aspect;
-    QMetaObject::invokeMethod(d->m_aspectThread->aspectManager(),
-                              "registerAspect",
-                              Qt::BlockingQueuedConnection,
-                              Q_ARG(Qt3DCore::QAbstractAspect*, aspect));
+    d->m_aspectManager->registerAspect(aspect);
 }
 
 /*!
@@ -327,10 +309,7 @@ void QAspectEngine::unregisterAspect(QAbstractAspect *aspect)
 
     // Tell the aspect manager to give the aspect a chance to do some cleanup
     // in its QAbstractAspect::onUnregistered() virtual
-    QMetaObject::invokeMethod(d->m_aspectThread->aspectManager(),
-                              "unregisterAspect",
-                              Qt::BlockingQueuedConnection,
-                              Q_ARG(Qt3DCore::QAbstractAspect*, aspect));
+    d->m_aspectManager->unregisterAspect(aspect);
 
     // Remove from our collection of named aspects (if present)
     const auto it = std::find_if(d->m_namedAspects.begin(), d->m_namedAspects.end(),
@@ -409,6 +388,19 @@ QVariant QAspectEngine::executeCommand(const QString &command)
 }
 
 /*!
+ * If using the manual run mode, this function executes the jobs for each aspect.
+ * It is blocking and won't return until all jobs have been completed.
+ *
+ * If you are using the QRenderAspect,
+ */
+void QAspectEngine::processFrame()
+{
+    Q_D(QAspectEngine);
+    Q_ASSERT(d->m_runMode == QAspectEngine::Manual);
+    d->m_aspectManager->processFrame();
+}
+
+/*!
  * Sets the \a root entity for the aspect engine.
  */
 void QAspectEngine::setRootEntity(QEntityPtr root)
@@ -446,7 +438,11 @@ void QAspectEngine::setRootEntity(QEntityPtr root)
     d->initNodeTree(root.data());
 
     // Traverse tree to generate a vector of creation changes
-    d->generateCreationChanges(root.data());
+    const QNodeCreatedChangeGenerator generator(root.data());
+    auto creationChanges = generator.creationChanges();
+
+    // Specify if the AspectManager should be driving the simulation loop or not
+    d->m_aspectManager->setRunMode(d->m_runMode);
 
     // Finally, tell the aspects about the new scene object tree. This is done
     // in a blocking manner to allow the aspects to get synchronized before the
@@ -455,14 +451,9 @@ void QAspectEngine::setRootEntity(QEntityPtr root)
     // TODO: Pass the creation changes via the arbiter rather than relying upon
     // an invokeMethod call.
     qCDebug(Aspects) << "Begin setting scene root on aspect manager";
-    QMetaObject::invokeMethod(d->m_aspectThread->aspectManager(),
-                              "setRootEntity",
-                              Qt::BlockingQueuedConnection,
-                              Q_ARG(Qt3DCore::QEntity*, root.data()),
-                              Q_ARG(QVector<Qt3DCore::QNodeCreatedChangeBasePtr>, d->m_creationChanges));
+    d->m_aspectManager->setRootEntity(root.data(), creationChanges);
     qCDebug(Aspects) << "Done setting scene root on aspect manager";
-
-    d->m_aspectThread->aspectManager()->enterSimulationLoop();
+    d->m_aspectManager->enterSimulationLoop();
 }
 
 /*!
@@ -474,6 +465,20 @@ QEntityPtr QAspectEngine::rootEntity() const
     return d->m_root;
 }
 
+void QAspectEngine::setRunMode(QAspectEngine::RunMode mode)
+{
+    Q_D(QAspectEngine);
+    d->m_runMode = mode;
+    if (d->m_aspectManager)
+        d->m_aspectManager->setRunMode(mode);
+}
+
+QAspectEngine::RunMode QAspectEngine::runMode() const
+{
+    Q_D(const QAspectEngine);
+    return d->m_runMode;
+}
+
 } // namespace Qt3DCore
 
 QT_END_NAMESPACE
diff --git a/src/core/aspects/qaspectengine.h b/src/core/aspects/qaspectengine.h
index 7f900ad52..1d5d7e220 100644
--- a/src/core/aspects/qaspectengine.h
+++ b/src/core/aspects/qaspectengine.h
@@ -60,12 +60,21 @@ class Q_3DCORESHARED_EXPORT QAspectEngine : public QObject
 {
     Q_OBJECT
 public:
+    enum RunMode {
+        Manual = 0,
+        Automatic
+    };
+    Q_ENUM(RunMode)
+
     explicit QAspectEngine(QObject *parent = nullptr);
     ~QAspectEngine();
 
     void setRootEntity(QEntityPtr root);
     QEntityPtr rootEntity() const;
 
+    void setRunMode(RunMode mode);
+    RunMode runMode() const;
+
     void registerAspect(QAbstractAspect *aspect);
     void registerAspect(const QString &name);
     void unregisterAspect(QAbstractAspect *aspect);
@@ -75,6 +84,8 @@ public:
 
     QVariant executeCommand(const QString &command);
 
+    void processFrame();
+
 private:
     Q_DECLARE_PRIVATE(QAspectEngine)
 };
diff --git a/src/core/aspects/qaspectengine_p.h b/src/core/aspects/qaspectengine_p.h
index 2d7d0fe93..7dad2a352 100644
--- a/src/core/aspects/qaspectengine_p.h
+++ b/src/core/aspects/qaspectengine_p.h
@@ -56,6 +56,7 @@
 #include <QtCore/qsharedpointer.h>
 
 #include <Qt3DCore/private/qaspectfactory_p.h>
+#include <Qt3DCore/private/qaspectengine_p.h>
 #include <QtCore/private/qobject_p.h>
 
 QT_BEGIN_NAMESPACE
@@ -64,8 +65,7 @@ namespace Qt3DCore {
 
 class QEntity;
 class QNode;
-class QAspectEngine;
-class QAspectThread;
+class QAspectManager;
 class QPostman;
 class QScene;
 
@@ -84,13 +84,14 @@ public:
     Q_DECLARE_PUBLIC(QAspectEngine)
 
     QAspectFactory m_factory;
-    QAspectThread *m_aspectThread;
+    QAspectManager *m_aspectManager;
     QPostman *m_postman;
     QScene *m_scene;
     QSharedPointer<QEntity> m_root;
     QVector<QAbstractAspect*> m_aspects;
     QHash<QString, QAbstractAspect *> m_namedAspects;
     bool m_initialized;
+    QAspectEngine::RunMode m_runMode;
 
 #if QT_CONFIG(qt3d_profile_jobs)
     Debug::AspectCommandDebugger *m_commandDebugger;
@@ -105,9 +106,6 @@ public:
     void initNode(QNode *node);
     void initEntity(QEntity *entity);
 
-    void generateCreationChanges(QNode *rootNode);
-    QVector<QNodeCreatedChangeBasePtr> m_creationChanges;
-
     static QAspectEnginePrivate *get(QAspectEngine *engine);
 };
 
diff --git a/src/core/aspects/qaspectmanager.cpp b/src/core/aspects/qaspectmanager.cpp
index e9642116a..0c16de882 100644
--- a/src/core/aspects/qaspectmanager.cpp
+++ b/src/core/aspects/qaspectmanager.cpp
@@ -61,6 +61,8 @@
 #include <Qt3DCore/private/qtickclock_p.h>
 #include <Qt3DCore/private/qtickclockservice_p.h>
 
+#include <QtCore/QCoreApplication>
+
 #if defined(QT3D_CORE_JOB_TIMING)
 #include <QElapsedTimer>
 #endif
@@ -69,6 +71,26 @@ QT_BEGIN_NAMESPACE
 
 namespace Qt3DCore {
 
+namespace  {
+
+class RequestFrameEvent : public QEvent
+{
+public:
+    RequestFrameEvent()
+        : QEvent(static_cast<QEvent::Type>(RequestFrameEvent::requestEventType))
+    {}
+
+    static int eventType() { return RequestFrameEvent::requestEventType; }
+
+private:
+    static int requestEventType;
+};
+
+int RequestFrameEvent::requestEventType = QEvent::registerEventType();
+
+} // anonymous
+
+
 /*!
     \class Qt3DCore::QAspectManager
     \internal
@@ -80,14 +102,10 @@ QAspectManager::QAspectManager(QObject *parent)
     , m_jobManager(new QAspectJobManager(this))
     , m_changeArbiter(new QChangeArbiter(this))
     , m_serviceLocator(new QServiceLocator())
-    , m_waitForEndOfSimulationLoop(0)
-    , m_waitForStartOfSimulationLoop(0)
-    , m_waitForEndOfExecLoop(0)
-    , m_waitForQuit(0)
+    , m_simulationLoopRunning(false)
+    , m_driveMode(QAspectEngine::Automatic)
 {
     qRegisterMetaType<QSurface *>("QSurface*");
-    m_runSimulationLoop.fetchAndStoreOrdered(0);
-    m_runMainLoop.fetchAndStoreOrdered(1);
     qCDebug(Aspects) << Q_FUNC_INFO;
 }
 
@@ -98,19 +116,37 @@ QAspectManager::~QAspectManager()
     delete m_scheduler;
 }
 
+void QAspectManager::setRunMode(QAspectEngine::RunMode mode)
+{
+    qCDebug(Aspects) << Q_FUNC_INFO << "Running Loop Drive Mode set to" << mode;
+    m_driveMode = mode;
+}
+
 // Main thread (called by QAspectEngine)
 void QAspectManager::enterSimulationLoop()
 {
     qCDebug(Aspects) << Q_FUNC_INFO;
-    m_runSimulationLoop.fetchAndStoreOrdered(1);
+    m_simulationLoopRunning = true;
+
+    // Retrieve the frame advance service. Defaults to timer based if there is no renderer.
+    QAbstractFrameAdvanceService *frameAdvanceService =
+            m_serviceLocator->service<QAbstractFrameAdvanceService>(QServiceLocator::FrameAdvanceService);
 
-    // Wake up QAspectThread's event loop
-    thread()->eventDispatcher()->wakeUp();
+    // Start the frameAdvanceService
+    frameAdvanceService->start();
 
-    // We wait for the setRootEntity on the aspectManager to have completed
-    // This ensures we cannot shutdown before the aspects have had a chance
-    // to be initialized
-    m_waitForStartOfSimulationLoop.acquire(1);
+    // We are about to enter the simulation loop. Give aspects a chance to do any last
+    // pieces of initialization
+    qCDebug(Aspects) << "Calling onEngineStartup() for each aspect";
+    for (QAbstractAspect *aspect : qAsConst(m_aspects)) {
+        qCDebug(Aspects) << "\t" << aspect->objectName();
+        aspect->onEngineStartup();
+    }
+    qCDebug(Aspects) << "Done calling onEngineStartup() for each aspect";
+
+    // Start running loop if Qt3D is in charge of driving it
+    if (m_driveMode == QAspectEngine::Automatic)
+        requestNextFrame();
 }
 
 // Main thread (called by QAspectEngine)
@@ -119,7 +155,7 @@ void QAspectManager::exitSimulationLoop()
     qCDebug(Aspects) << Q_FUNC_INFO;
 
     // If this fails, simulation loop is already exited so nothing to do
-    if (!m_runSimulationLoop.testAndSetOrdered(1, 0)) {
+    if (!m_simulationLoopRunning) {
         qCDebug(Aspects) << "Simulation loop was not running. Nothing to do";
         return;
     }
@@ -141,17 +177,26 @@ void QAspectManager::exitSimulationLoop()
     for (QAbstractAspect *aspect : qAsConst(m_aspects))
         aspect->d_func()->onEngineAboutToShutdown();
 
+    // Process any pending changes from the frontend before we shut the aspects down
+    m_changeArbiter->syncChanges();
+
+    // Give aspects a chance to perform any shutdown actions. This may include unqueuing
+    // any blocking work on the main thread that could potentially deadlock during shutdown.
+    qCDebug(Aspects) << "Calling onEngineShutdown() for each aspect";
+    for (QAbstractAspect *aspect : qAsConst(m_aspects)) {
+        qCDebug(Aspects) << "\t" << aspect->objectName();
+        aspect->onEngineShutdown();
+    }
+    qCDebug(Aspects) << "Done calling onEngineShutdown() for each aspect";
 
-    qCDebug(Aspects) << "exitSimulationLoop waiting for exec loop to terminate";
-    // Wait until the simulation loop is fully exited and the aspects are done
-    // processing any final changes and have had onEngineShutdown() called on them
-    m_waitForEndOfSimulationLoop.acquire(1);
+
+    m_simulationLoopRunning = false;
     qCDebug(Aspects) << "exitSimulationLoop completed";
 }
 
 bool QAspectManager::isShuttingDown() const
 {
-    return !m_runSimulationLoop.load();
+    return !m_simulationLoopRunning;
 }
 
 /*!
@@ -184,7 +229,7 @@ void QAspectManager::shutdown()
     // Aspects must be deleted in the Thread they were created in
 }
 
-// QAspectThread:: queued invoked by QAspectEngine::setRootEntity
+// MainThread called by QAspectEngine::setRootEntity
 void QAspectManager::setRootEntity(Qt3DCore::QEntity *root, const QVector<Qt3DCore::QNodeCreatedChangeBasePtr> &changes)
 {
     qCDebug(Aspects) << Q_FUNC_INFO;
@@ -251,118 +296,6 @@ void QAspectManager::unregisterAspect(Qt3DCore::QAbstractAspect *aspect)
     qCDebug(Aspects) << "Completed unregistering aspect";
 }
 
-void QAspectManager::exec()
-{
-    // Gentlemen, start your engines
-    QEventLoop eventLoop;
-
-    // Enter the engine loop
-    qCDebug(Aspects) << Q_FUNC_INFO << "***** Entering main loop *****";
-    while (m_runMainLoop.load()) {
-        // Process events until we're told to start the simulation loop
-        while (m_runMainLoop.load() && !m_runSimulationLoop.load())
-            eventLoop.processEvents(QEventLoop::AllEvents | QEventLoop::WaitForMoreEvents);
-
-        if (!m_runSimulationLoop.load())
-            break;
-
-        // Retrieve the frame advance service. Defaults to timer based if there is no renderer.
-        QAbstractFrameAdvanceService *frameAdvanceService =
-                m_serviceLocator->service<QAbstractFrameAdvanceService>(QServiceLocator::FrameAdvanceService);
-
-        // Start the frameAdvanceService
-        frameAdvanceService->start();
-
-        // We are about to enter the simulation loop. Give aspects a chance to do any last
-        // pieces of initialization
-        qCDebug(Aspects) << "Calling onEngineStartup() for each aspect";
-        for (QAbstractAspect *aspect : qAsConst(m_aspects)) {
-            qCDebug(Aspects) << "\t" << aspect->objectName();
-            aspect->onEngineStartup();
-        }
-        qCDebug(Aspects) << "Done calling onEngineStartup() for each aspect";
-        m_waitForStartOfSimulationLoop.release(1);
-
-        // Only enter main simulation loop once the renderer and other aspects are initialized
-        while (m_runSimulationLoop.load()) {
-            qint64 t = frameAdvanceService->waitForNextFrame();
-
-            // Distribute accumulated changes. This includes changes sent from the frontend
-            // to the backend nodes. We call this before the call to m_scheduler->update() to ensure
-            // that any property changes do not set dirty flags in a data race with the renderer's
-            // submission thread which may be looking for dirty flags, acting upon them and then
-            // clearing the dirty flags.
-            //
-            // Doing this as the first call in the new frame ensures the lock free approach works
-            // without any such data race.
-#if QT_CONFIG(qt3d_profile_jobs)
-            const quint32 arbiterId = 4096;
-            JobRunStats changeArbiterStats;
-            changeArbiterStats.jobId.typeAndInstance[0] = arbiterId;
-            changeArbiterStats.jobId.typeAndInstance[1] = 0;
-            changeArbiterStats.threadId = reinterpret_cast<quint64>(QThread::currentThreadId());
-            changeArbiterStats.startTime = QThreadPooler::m_jobsStatTimer.nsecsElapsed();
-#endif
-            m_changeArbiter->syncChanges();
-#if QT_CONFIG(qt3d_profile_jobs)
-            changeArbiterStats.endTime = QThreadPooler::m_jobsStatTimer.nsecsElapsed();
-            QThreadPooler::addJobLogStatsEntry(changeArbiterStats);
-#endif
-
-            // For each Aspect
-            // Ask them to launch set of jobs for the current frame
-            // Updates matrices, bounding volumes, render bins ...
-#if defined(QT3D_CORE_JOB_TIMING)
-            QElapsedTimer timer;
-            timer.start();
-#endif
-            m_scheduler->scheduleAndWaitForFrameAspectJobs(t);
-#if defined(QT3D_CORE_JOB_TIMING)
-            qDebug() << "Jobs took" << timer.nsecsElapsed() / 1.0e6;
-#endif
-
-            // Process any pending events
-            eventLoop.processEvents();
-        } // End of simulation loop
-
-        // Process any pending changes from the frontend before we shut the aspects down
-        m_changeArbiter->syncChanges();
-
-        // Give aspects a chance to perform any shutdown actions. This may include unqueuing
-        // any blocking work on the main thread that could potentially deadlock during shutdown.
-        qCDebug(Aspects) << "Calling onEngineShutdown() for each aspect";
-        for (QAbstractAspect *aspect : qAsConst(m_aspects)) {
-            qCDebug(Aspects) << "\t" << aspect->objectName();
-            aspect->onEngineShutdown();
-        }
-        qCDebug(Aspects) << "Done calling onEngineShutdown() for each aspect";
-
-        // Wake up the main thread which is waiting for us inside of exitSimulationLoop()
-        m_waitForEndOfSimulationLoop.release(1);
-    } // End of main loop
-    qCDebug(Aspects) << Q_FUNC_INFO << "***** Exited main loop *****";
-
-    m_waitForEndOfExecLoop.release(1);
-    m_waitForQuit.acquire(1);
-}
-
-void QAspectManager::quit()
-{
-    qCDebug(Aspects) << Q_FUNC_INFO;
-
-    Q_ASSERT_X(m_runSimulationLoop.load() == 0, "QAspectManagr::quit()", "Inner loop is still running");
-    m_runMainLoop.fetchAndStoreOrdered(0);
-
-    // Wake up QAspectThread's event loop if needed
-    thread()->eventDispatcher()->wakeUp();
-
-    // We need to wait for the QAspectManager exec loop to terminate
-    m_waitForEndOfExecLoop.acquire(1);
-    m_waitForQuit.release(1);
-
-    qCDebug(Aspects) << Q_FUNC_INFO << "Exiting";
-}
-
 const QVector<QAbstractAspect *> &QAspectManager::aspects() const
 {
     return m_aspects;
@@ -383,7 +316,88 @@ QServiceLocator *QAspectManager::serviceLocator() const
     return m_serviceLocator.data();
 }
 
+/*!
+    \internal
+    \brief Drives the Qt3D simulation loop in the main thread
+ */
+bool QAspectManager::event(QEvent *e)
+{
+    if (e->type() == RequestFrameEvent::eventType()) {
+
+        // Process current frame
+        processFrame();
+
+        // Request next frame if we are still running and if Qt3D is driving
+        // the loop
+        if (m_simulationLoopRunning && m_driveMode == QAspectEngine::Automatic)
+            requestNextFrame();
+    }
+
+    return QObject::event(e);
+}
+
+void QAspectManager::requestNextFrame()
+{
+    qCDebug(Aspects) << "Requesting new Frame";
+    // Post event in the event loop to force
+    // next frame to be processed
+    qApp->postEvent(this, new RequestFrameEvent());
+}
+
+void QAspectManager::processFrame()
+{
+    qCDebug(Aspects) << "Processing Frame";
+
+    // Retrieve the frame advance service. Defaults to timer based if there is no renderer.
+    QAbstractFrameAdvanceService *frameAdvanceService =
+            m_serviceLocator->service<QAbstractFrameAdvanceService>(QServiceLocator::FrameAdvanceService);
+
+    const qint64 t = frameAdvanceService->waitForNextFrame();
+
+    // Distribute accumulated changes. This includes changes sent from the frontend
+    // to the backend nodes. We call this before the call to m_scheduler->update() to ensure
+    // that any property changes do not set dirty flags in a data race with the renderer's
+    // submission thread which may be looking for dirty flags, acting upon them and then
+    // clearing the dirty flags.
+    //
+    // Doing this as the first call in the new frame ensures the lock free approach works
+    // without any such data race.
+#if QT_CONFIG(qt3d_profile_jobs)
+    const quint32 arbiterId = 4096;
+    JobRunStats changeArbiterStats;
+    changeArbiterStats.jobId.typeAndInstance[0] = arbiterId;
+    changeArbiterStats.jobId.typeAndInstance[1] = 0;
+    changeArbiterStats.threadId = reinterpret_cast<quint64>(QThread::currentThreadId());
+    changeArbiterStats.startTime = QThreadPooler::m_jobsStatTimer.nsecsElapsed();
+#endif
+    const auto dirtyFrontEndNodes = m_changeArbiter->takeDirtyFrontEndNodes();
+    if (dirtyFrontEndNodes.size())
+        for (QAbstractAspect *aspect : qAsConst(m_aspects))
+           aspect->syncDirtyFrontEndNodes(dirtyFrontEndNodes);
+    // TO DO: Having this done in the main thread actually means aspects could just
+    // as simply read info out of the Frontend classes without risk of introducing
+    // races. This could therefore be removed for Qt 6.
+    m_changeArbiter->syncChanges();
+#if QT_CONFIG(qt3d_profile_jobs)
+    changeArbiterStats.endTime = QThreadPooler::m_jobsStatTimer.nsecsElapsed();
+    QThreadPooler::addJobLogStatsEntry(changeArbiterStats);
+#endif
+
+    // For each Aspect
+    // Ask them to launch set of jobs for the current frame
+    // Updates matrices, bounding volumes, render bins ...
+#if defined(QT3D_CORE_JOB_TIMING)
+    QElapsedTimer timer;
+    timer.start();
+#endif
+    m_scheduler->scheduleAndWaitForFrameAspectJobs(t);
+#if defined(QT3D_CORE_JOB_TIMING)
+    qDebug() << "Jobs took" << timer.nsecsElapsed() / 1.0e6;
+#endif
+
+    // TODO sync backend changes to frontend
+}
+
 } // namespace Qt3DCore
 
 QT_END_NAMESPACE
-
diff --git a/src/core/aspects/qaspectmanager_p.h b/src/core/aspects/qaspectmanager_p.h
index de978b8e9..d654f7b5a 100644
--- a/src/core/aspects/qaspectmanager_p.h
+++ b/src/core/aspects/qaspectmanager_p.h
@@ -52,6 +52,7 @@
 //
 
 #include <Qt3DCore/qnodecreatedchange.h>
+#include <Qt3DCore/qaspectengine.h>
 #include <QtCore/QObject>
 #include <QtCore/QScopedPointer>
 #include <QtCore/QSemaphore>
@@ -82,6 +83,7 @@ public:
     explicit QAspectManager(QObject *parent = 0);
     ~QAspectManager();
 
+    void setRunMode(QAspectEngine::RunMode mode);
     void enterSimulationLoop();
     void exitSimulationLoop();
 
@@ -90,14 +92,12 @@ public:
 public Q_SLOTS:
     void initialize();
     void shutdown();
+    void processFrame();
 
     void setRootEntity(Qt3DCore::QEntity *root, const QVector<Qt3DCore::QNodeCreatedChangeBasePtr> &changes);
     void registerAspect(Qt3DCore::QAbstractAspect *aspect);
     void unregisterAspect(Qt3DCore::QAbstractAspect *aspect);
 
-    void exec();
-    void quit();
-
 public:
     const QVector<QAbstractAspect *> &aspects() const;
     QAbstractAspectJobManager *jobManager() const;
@@ -105,19 +105,20 @@ public:
     QServiceLocator *serviceLocator() const;
 
 private:
+    bool event(QEvent *event) override;
+    void requestNextFrame();
+
     QVector<QAbstractAspect *> m_aspects;
     QEntity *m_root;
     QVariantMap m_data;
     QScheduler *m_scheduler;
     QAbstractAspectJobManager *m_jobManager;
     QChangeArbiter *m_changeArbiter;
-    QAtomicInt m_runSimulationLoop;
-    QAtomicInt m_runMainLoop;
     QScopedPointer<QServiceLocator> m_serviceLocator;
-    QSemaphore m_waitForEndOfSimulationLoop;
-    QSemaphore m_waitForStartOfSimulationLoop;
-    QSemaphore m_waitForEndOfExecLoop;
-    QSemaphore m_waitForQuit;
+    bool m_mainLoopRunning;
+    bool m_simulationLoopRunning;
+    QAspectEngine::RunMode m_driveMode;
+
 };
 
 } // namespace Qt3DCore
diff --git a/src/core/aspects/qaspectthread.cpp b/src/core/aspects/qaspectthread.cpp
deleted file mode 100644
index 31715b04e..000000000
--- a/src/core/aspects/qaspectthread.cpp
+++ /dev/null
@@ -1,99 +0,0 @@
-/****************************************************************************
-**
-** 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 "qaspectthread_p.h"
-
-#include <QtCore/QMutexLocker>
-
-#include <Qt3DCore/private/qaspectmanager_p.h>
-#include <Qt3DCore/private/corelogging_p.h>
-
-QT_BEGIN_NAMESPACE
-
-namespace Qt3DCore {
-
-QAspectThread::QAspectThread(QObject *parent)
-    : QThread(parent),
-      m_aspectManager(nullptr),
-      m_semaphore(0)
-{
-    qCDebug(Aspects) << Q_FUNC_INFO;
-}
-
-QAspectThread::~QAspectThread()
-{
-}
-
-void QAspectThread::waitForStart(Priority priority)
-{
-    qCDebug(Aspects) << "Starting QAspectThread and going to sleep until it is ready for us...";
-    start(priority);
-    m_semaphore.acquire();
-    qCDebug(Aspects) << "QAspectThead is now ready & calling thread is now awake again";
-}
-
-void QAspectThread::run()
-{
-    qCDebug(Aspects) << "Entering void QAspectThread::run()";
-
-    m_aspectManager = new QAspectManager;
-
-    // Load and initialize the aspects and any other core services
-    // Done before releasing condition to make sure that Qml Components
-    // Are exposed prior to Qml Engine source being set
-    m_aspectManager->initialize();
-
-    // Wake up the calling thread now that our worker objects are ready for action
-    m_semaphore.release();
-
-    // Enter the main loop
-    m_aspectManager->exec();
-
-    // Clean up
-    m_aspectManager->shutdown();
-
-    // Delete the aspect manager while we're still in the thread
-    delete m_aspectManager;
-
-    qCDebug(Aspects) << "Exiting void QAspectThread::run()";
-}
-
-} // namespace Qt3DCore
-
-QT_END_NAMESPACE
diff --git a/src/core/aspects/qaspectthread_p.h b/src/core/aspects/qaspectthread_p.h
deleted file mode 100644
index 8ae9ff86d..000000000
--- a/src/core/aspects/qaspectthread_p.h
+++ /dev/null
@@ -1,88 +0,0 @@
-/****************************************************************************
-**
-** 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.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
-
-#ifndef QT3DCORE_QASPECTTHREAD_P_H
-#define QT3DCORE_QASPECTTHREAD_P_H
-
-//
-//  W A R N I N G
-//  -------------
-//
-// This file is not part of the Qt API.  It exists for the convenience
-// of other Qt classes.  This header file may change from version to
-// version without notice, or even be removed.
-//
-// We mean it.
-//
-
-#include <Qt3DCore/qt3dcore_global.h>
-#include <QtCore/QSemaphore>
-#include <QtCore/QThread>
-
-
-QT_BEGIN_NAMESPACE
-
-namespace Qt3DCore {
-
-class QAspectManager;
-
-class QAspectThread : public QThread
-{
-    Q_OBJECT
-public:
-    explicit QAspectThread(QObject *parent = 0);
-    ~QAspectThread();
-
-    void waitForStart(Priority priority);
-
-    QAspectManager *aspectManager() const { return m_aspectManager; }
-
-protected:
-    void run() override;
-
-private:
-    QAspectManager *m_aspectManager;
-    QSemaphore m_semaphore;
-};
-
-} // namespace Qt3DCore
-
-QT_END_NAMESPACE
-
-#endif // QT3DCORE_QASPECTTHREAD_P_H
diff --git a/src/core/jobs/qthreadpooler.cpp b/src/core/jobs/qthreadpooler.cpp
index ca123ddad..0e9af58dd 100644
--- a/src/core/jobs/qthreadpooler.cpp
+++ b/src/core/jobs/qthreadpooler.cpp
@@ -212,7 +212,7 @@ void QThreadPooler::addJobLogStatsEntry(JobRunStats &stats)
     jobStatsCached.localData()->push_back(stats);
 }
 
-// Called after jobs have been executed (AspectThread QAspectJobManager::enqueueJobs)
+// Called after jobs have been executed (MainThread QAspectJobManager::enqueueJobs)
 void QThreadPooler::writeFrameJobLogStats()
 {
     static QScopedPointer<QFile> traceFile;
@@ -268,7 +268,7 @@ void QThreadPooler::writeFrameJobLogStats()
     ++frameId;
 }
 
-// Called from Submission thread
+// Called from Submission thread (which can be main thread in Manual drive mode)
 void QThreadPooler::addSubmissionLogStatsEntry(JobRunStats &stats)
 {
     QMutexLocker lock(&localStoragesMutex);
@@ -276,6 +276,12 @@ void QThreadPooler::addSubmissionLogStatsEntry(JobRunStats &stats)
         submissionStorage = new QVector<JobRunStats>;
         jobStatsCached.setLocalData(submissionStorage);
     }
+
+    // Handle the case where submission thread is also the main thread (Scene/Manual drive modes with no RenderThread)
+    if (submissionStorage == nullptr && jobStatsCached.hasLocalData())
+        submissionStorage = new QVector<JobRunStats>;
+
+    // When having no submission thread this can be null
     submissionStorage->push_back(stats);
 }
 
diff --git a/src/core/nodes/qbackendnode.cpp b/src/core/nodes/qbackendnode.cpp
index f10bf5769..3eb1cd9f7 100644
--- a/src/core/nodes/qbackendnode.cpp
+++ b/src/core/nodes/qbackendnode.cpp
@@ -256,16 +256,16 @@ void QBackendNode::setEnabled(bool enabled) Q_DECL_NOTHROW
 void QBackendNode::sceneChangeEvent(const QSceneChangePtr &e)
 {
     Q_D(QBackendNode);
-    auto propertyChange = qSharedPointerCast<QPropertyUpdatedChange>(e);
 
     switch (e->type()) {
-        case PropertyUpdated: {
-            if (propertyChange->propertyName() == QByteArrayLiteral("enabled"))
-                d->m_enabled = propertyChange->value().toBool();
-            break;
-        }
-        default:
-            break;
+    case PropertyUpdated: {
+        auto propertyChange = qSharedPointerCast<QPropertyUpdatedChange>(e);
+        if (propertyChange->propertyName() == QByteArrayLiteral("enabled"))
+            d->m_enabled = propertyChange->value().toBool();
+        break;
+    }
+    default:
+        break;
     }
 }
 
diff --git a/src/core/nodes/qcomponent.cpp b/src/core/nodes/qcomponent.cpp
index f67989b1e..2fe3c8094 100644
--- a/src/core/nodes/qcomponent.cpp
+++ b/src/core/nodes/qcomponent.cpp
@@ -73,7 +73,7 @@ void QComponentPrivate::addEntity(QEntity *entity)
         m_scene->addEntityForComponent(m_id, entity->id());
     }
 
-    const auto componentAddedChange = QComponentAddedChangePtr::create(q, entity);
+    const auto componentAddedChange = QComponentAddedChangePtr::create(q, entity);  // TODOSYNC notify backend directly
     notifyObservers(componentAddedChange);
     Q_EMIT q->addedToEntity(entity);
 }
@@ -86,7 +86,7 @@ void QComponentPrivate::removeEntity(QEntity *entity)
 
     m_entities.removeAll(entity);
 
-    const auto componentRemovedChange = QComponentRemovedChangePtr::create(q, entity);
+    const auto componentRemovedChange = QComponentRemovedChangePtr::create(q, entity);  // TODOSYNC notify backend directly
     notifyObservers(componentRemovedChange);
     Q_EMIT q->removedFromEntity(entity);
 }
diff --git a/src/core/nodes/qentity.cpp b/src/core/nodes/qentity.cpp
index 1d16e828e..a1f7d2859 100644
--- a/src/core/nodes/qentity.cpp
+++ b/src/core/nodes/qentity.cpp
@@ -105,7 +105,7 @@ void QEntityPrivate::removeDestroyedComponent(QComponent *comp)
     Q_Q(QEntity);
 
     if (m_changeArbiter) {
-        const auto componentRemovedChange = QComponentRemovedChangePtr::create(q, comp);
+        const auto componentRemovedChange = QComponentRemovedChangePtr::create(q, comp);  // TODOSYNC notify backend directly
         notifyObservers(componentRemovedChange);
     }
 
@@ -187,7 +187,7 @@ void QEntity::addComponent(QComponent *comp)
     d->registerPrivateDestructionHelper(comp, &QEntityPrivate::removeDestroyedComponent);
 
     if (d->m_changeArbiter) {
-        const auto componentAddedChange = QComponentAddedChangePtr::create(this, comp);
+        const auto componentAddedChange = QComponentAddedChangePtr::create(this, comp);     // TODOSYNC notify backend directly
         d->notifyObservers(componentAddedChange);
     }
     static_cast<QComponentPrivate *>(QComponentPrivate::get(comp))->addEntity(this);
diff --git a/src/core/nodes/qnode.cpp b/src/core/nodes/qnode.cpp
index 900c3f8ce..45d58bd8c 100644
--- a/src/core/nodes/qnode.cpp
+++ b/src/core/nodes/qnode.cpp
@@ -385,48 +385,13 @@ void QNodePrivate::unregisterNotifiedProperties()
 
 void QNodePrivate::propertyChanged(int propertyIndex)
 {
+    Q_UNUSED(propertyIndex);
+
     // Bail out early if we can to avoid the cost below
     if (m_blockNotifications)
         return;
 
-    const auto toBackendValue = [](const QVariant &data) -> QVariant
-    {
-        if (data.canConvert<QNode*>()) {
-            QNode *node = data.value<QNode*>();
-
-            // Ensure the node and all ancestors have issued their node creation changes.
-            // We can end up here if a newly created node with a parent is immediately set
-            // as a property on another node. In this case the deferred call to
-            // _q_postConstructorInit() will not have happened yet as the event
-            // loop will still be blocked. We need to do this for all ancestors,
-            // since the subtree of this node otherwise can end up on the backend
-            // with a reference to a non-existent parent.
-            if (node)
-                QNodePrivate::get(node)->_q_ensureBackendNodeCreated();
-
-            const QNodeId id = node ? node->id() : QNodeId();
-            return QVariant::fromValue(id);
-        }
-
-        return data;
-    };
-
-    Q_Q(QNode);
-
-    const QMetaProperty property = q->metaObject()->property(propertyIndex);
-
-    const QVariant data = property.read(q);
-
-    if (data.type() == QVariant::List) {
-        QSequentialIterable iterable = data.value<QSequentialIterable>();
-        QVariantList variants;
-        variants.reserve(iterable.size());
-        for (const auto &v : iterable)
-            variants.append(toBackendValue(v));
-        notifyPropertyChange(property.name(), variants);
-    } else {
-        notifyPropertyChange(property.name(), toBackendValue(data));
-    }
+    update();
 }
 
 /*!
@@ -498,8 +463,13 @@ void QNodePrivate::addEntityComponentToScene(QNode *root)
 // Called in the main thread by QScene -> following QEvent::childAdded / addChild
 void QNodePrivate::setArbiter(QLockableObserverInterface *arbiter)
 {
-    if (m_changeArbiter && m_changeArbiter != arbiter)
+    if (m_changeArbiter && m_changeArbiter != arbiter) {
         unregisterNotifiedProperties();
+
+        // Remove node from dirtyFrontendNodeList on old arbiter
+        Q_Q(QNode);
+        m_changeArbiter->removeDirtyFrontEndNode(q);
+    }
     m_changeArbiter = static_cast<QAbstractArbiter *>(arbiter);
     if (m_changeArbiter)
         registerNotifiedProperties();
@@ -626,26 +596,26 @@ QScene *QNodePrivate::scene() const
  */
 void QNodePrivate::notifyPropertyChange(const char *name, const QVariant &value)
 {
+    Q_UNUSED(name);
+    Q_UNUSED(value);
+
     // Bail out early if we can to avoid operator new
     if (m_blockNotifications)
         return;
 
-    auto e = QPropertyUpdatedChangePtr::create(m_id);
-    e->setPropertyName(name);
-    e->setValue(value);
-    notifyObservers(e);
+    update();
 }
 
 void QNodePrivate::notifyDynamicPropertyChange(const QByteArray &name, const QVariant &value)
 {
+    Q_UNUSED(name);
+    Q_UNUSED(value);
+
     // Bail out early if we can to avoid operator new
     if (m_blockNotifications)
         return;
 
-    auto e = QDynamicPropertyUpdatedChangePtr::create(m_id);
-    e->setPropertyName(name);
-    e->setValue(value);
-    notifyObservers(e);
+    update();
 }
 
 /*!
@@ -704,6 +674,14 @@ void QNodePrivate::updatePropertyTrackMode()
     }
 }
 
+void QNodePrivate::update()
+{
+    if (m_changeArbiter) {
+        Q_Q(QNode);
+        m_changeArbiter->addDirtyFrontEndNode(q);
+    }
+}
+
 /*!
     \internal
  */
diff --git a/src/core/nodes/qnode_p.h b/src/core/nodes/qnode_p.h
index 511a0e562..990c2caeb 100644
--- a/src/core/nodes/qnode_p.h
+++ b/src/core/nodes/qnode_p.h
@@ -89,6 +89,8 @@ public:
     void insertTree(QNode *treeRoot, int depth = 0);
     void updatePropertyTrackMode();
 
+    void update();
+
     Q_DECLARE_PUBLIC(QNode)
 
     // For now this just protects access to the m_changeArbiter.
diff --git a/src/core/qchangearbiter.cpp b/src/core/qchangearbiter.cpp
index 8cfc4b066..6ad72c895 100644
--- a/src/core/qchangearbiter.cpp
+++ b/src/core/qchangearbiter.cpp
@@ -266,6 +266,22 @@ void QChangeArbiter::sceneChangeEventWithLock(const QSceneChangeList &e)
     emit receivedChange();
 }
 
+void QChangeArbiter::addDirtyFrontEndNode(QNode *node)
+{
+    if (!m_dirtyFrontEndNodes.contains(node))
+        m_dirtyFrontEndNodes += node;
+}
+
+void QChangeArbiter::removeDirtyFrontEndNode(QNode *node)
+{
+    m_dirtyFrontEndNodes.removeOne(node);
+}
+
+QVector<QNode *> QChangeArbiter::takeDirtyFrontEndNodes()
+{
+    return std::move(m_dirtyFrontEndNodes);
+}
+
 // Either we have the postman or we could make the QChangeArbiter agnostic to the postman
 // but that would require adding it to every QObserverList in m_aspectObservations.
 void QChangeArbiter::setPostman(QAbstractPostman *postman)
diff --git a/src/core/qchangearbiter_p.h b/src/core/qchangearbiter_p.h
index 1f453ff56..48fc4ca8c 100644
--- a/src/core/qchangearbiter_p.h
+++ b/src/core/qchangearbiter_p.h
@@ -81,6 +81,8 @@ class Q_3DCORE_PRIVATE_EXPORT QAbstractArbiter : public QLockableObserverInterfa
 {
 public:
     virtual QAbstractPostman *postman() const = 0;
+    virtual void addDirtyFrontEndNode(QNode *node) = 0;
+    virtual void removeDirtyFrontEndNode(QNode *node) = 0;
 };
 
 class Q_3DCORE_PRIVATE_EXPORT QChangeArbiter final
@@ -89,7 +91,7 @@ class Q_3DCORE_PRIVATE_EXPORT QChangeArbiter final
 {
     Q_OBJECT
 public:
-    explicit QChangeArbiter(QObject *parent = 0);
+    explicit QChangeArbiter(QObject *parent = nullptr);
     ~QChangeArbiter();
 
     void initialize(Qt3DCore::QAbstractAspectJobManager *jobManager);
@@ -109,8 +111,12 @@ public:
     void sceneChangeEventWithLock(const QSceneChangePtr &e) override; // QLockableObserverInterface impl
     void sceneChangeEventWithLock(const QSceneChangeList &e) override; // QLockableObserverInterface impl
 
-    Q_INVOKABLE void setPostman(Qt3DCore::QAbstractPostman *postman);
-    Q_INVOKABLE void setScene(Qt3DCore::QScene *scene);
+    void addDirtyFrontEndNode(QNode *node) override;
+    void removeDirtyFrontEndNode(QNode *node) override;
+    QVector<QNode *> takeDirtyFrontEndNodes();
+
+    void setPostman(Qt3DCore::QAbstractPostman *postman);
+    void setScene(Qt3DCore::QScene *scene);
 
     QAbstractPostman *postman() const final;
     QScene *scene() const;
@@ -155,6 +161,8 @@ private:
     QList<QChangeQueue *> m_lockingChangeQueues;
     QAbstractPostman *m_postman;
     QScene *m_scene;
+
+    QVector<QNode *> m_dirtyFrontEndNodes;
 };
 
 } // namespace Qt3DCore
diff --git a/src/core/qscene.cpp b/src/core/qscene.cpp
index c94272e90..1b8996e8d 100644
--- a/src/core/qscene.cpp
+++ b/src/core/qscene.cpp
@@ -68,7 +68,7 @@ public:
     QMultiHash<QNodeId, QObservableInterface *> m_observablesLookupTable;
     QHash<QObservableInterface *, QNodeId> m_observableToUuid;
     QHash<QNodeId, QScene::NodePropertyTrackData> m_nodePropertyTrackModeLookupTable;
-    QLockableObserverInterface *m_arbiter;
+    QAbstractArbiter *m_arbiter;
     QScopedPointer<NodePostConstructorInit> m_postConstructorInit;
     mutable QReadWriteLock m_lock;
     mutable QReadWriteLock m_nodePropertyTrackModeLock;
@@ -183,13 +183,13 @@ QNode *QScene::rootNode() const
     return d->m_rootNode;
 }
 
-void QScene::setArbiter(QLockableObserverInterface *arbiter)
+void QScene::setArbiter(QAbstractArbiter *arbiter)
 {
     Q_D(QScene);
     d->m_arbiter = arbiter;
 }
 
-QLockableObserverInterface *QScene::arbiter() const
+QAbstractArbiter *QScene::arbiter() const
 {
     Q_D(const QScene);
     return d->m_arbiter;
diff --git a/src/core/qscene_p.h b/src/core/qscene_p.h
index afcfb9b40..cdb85ebe6 100644
--- a/src/core/qscene_p.h
+++ b/src/core/qscene_p.h
@@ -65,6 +65,7 @@ namespace Qt3DCore {
 class QScenePrivate;
 class QAspectEngine;
 class NodePostConstructorInit;
+class QAbstractArbiter;
 
 typedef QList<QObservableInterface *> QObservableList;
 
@@ -88,8 +89,8 @@ public:
 
     QNode *rootNode() const;
 
-    void setArbiter(Qt3DCore::QLockableObserverInterface *arbiter);
-    Qt3DCore::QLockableObserverInterface *arbiter() const;
+    void setArbiter(QAbstractArbiter *arbiter);
+    QAbstractArbiter *arbiter() const;
 
     // Component -> Entities
     QVector<QNodeId> entitiesForComponent(QNodeId id) const;
diff --git a/src/core/services/qdownloadhelperservice.cpp b/src/core/services/qdownloadhelperservice.cpp
index 4cd89c5d0..deddf3ae0 100644
--- a/src/core/services/qdownloadhelperservice.cpp
+++ b/src/core/services/qdownloadhelperservice.cpp
@@ -39,10 +39,10 @@
 
 #include "qdownloadhelperservice_p.h"
 #include "qdownloadnetworkworker_p.h"
+#include <QtCore/QThread>
 #include <Qt3DCore/QAspectEngine>
 #include <Qt3DCore/private/qabstractserviceprovider_p.h>
 #include <Qt3DCore/private/qaspectengine_p.h>
-#include <Qt3DCore/private/qaspectthread_p.h>
 #include <Qt3DCore/private/qaspectmanager_p.h>
 #include <Qt3DCore/private/qservicelocator_p.h>
 
@@ -196,7 +196,7 @@ QString QDownloadHelperService::urlToLocalFileOrQrc(const QUrl &url)
 QDownloadHelperService *QDownloadHelperService::getService(QAspectEngine *engine)
 {
     auto enginePrivate = Qt3DCore::QAspectEnginePrivate::get(engine);
-    return enginePrivate->m_aspectThread->aspectManager()->serviceLocator()->downloadHelperService();
+    return enginePrivate->m_aspectManager->serviceLocator()->downloadHelperService();
 }
 
 bool QDownloadHelperService::isLocal(const QUrl &url)