QAspectEngine: add run loop driving modes

Can be either Automatic (Qt3D is in charge or driving it) or manual
where the user has to call QAspectManager::processFrame() manually.

Change-Id: I3e41d24aea0ddc5cce61328d9731b23f91b54215
Reviewed-by: Mike Krus <mike.krus@kdab.com>

5 files changed, 61 insertions, 6 deletions

diff --git a/src/core/aspects/qaspectengine.cpp b/src/core/aspects/qaspectengine.cpp
index 2e7e51247..9c98e9613 100644
--- a/src/core/aspects/qaspectengine.cpp
+++ b/src/core/aspects/qaspectengine.cpp
@@ -77,6 +77,7 @@ QAspectEnginePrivate::QAspectEnginePrivate()
     , 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
@@ -393,6 +394,19 @@ 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)
@@ -432,6 +446,9 @@ void QAspectEngine::setRootEntity(QEntityPtr root)
     // Traverse tree to generate a vector of creation changes
     d->generateCreationChanges(root.data());
 
+    // 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
     // main thread starts triggering potentially more notifications
@@ -453,6 +470,20 @@ 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 9c042b5a5..e1aaa9de9 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
@@ -64,7 +65,6 @@ namespace Qt3DCore {
 
 class QEntity;
 class QNode;
-class QAspectEngine;
 class QAspectManager;
 class QPostman;
 class QScene;
@@ -91,6 +91,7 @@ public:
     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;
diff --git a/src/core/aspects/qaspectmanager.cpp b/src/core/aspects/qaspectmanager.cpp
index a028e38cb..6502590d8 100644
--- a/src/core/aspects/qaspectmanager.cpp
+++ b/src/core/aspects/qaspectmanager.cpp
@@ -103,6 +103,7 @@ QAspectManager::QAspectManager(QObject *parent)
     , m_changeArbiter(new QChangeArbiter(this))
     , m_serviceLocator(new QServiceLocator())
     , m_simulationLoopRunning(false)
+    , m_driveMode(QAspectEngine::Automatic)
 {
     qRegisterMetaType<QSurface *>("QSurface*");
     qCDebug(Aspects) << Q_FUNC_INFO;
@@ -115,6 +116,12 @@ 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()
 {
@@ -137,8 +144,9 @@ void QAspectManager::enterSimulationLoop()
     }
     qCDebug(Aspects) << "Done calling onEngineStartup() for each aspect";
 
-    // Trigger event loop
-    requestNextFrame();
+    // Start running loop if Qt3D is in charge of driving it
+    if (m_driveMode == QAspectEngine::Automatic)
+        requestNextFrame();
 }
 
 // Main thread (called by QAspectEngine)
@@ -319,8 +327,9 @@ bool QAspectManager::event(QEvent *e)
         // Process current frame
         processFrame();
 
-        // Request next frame if we are still running
-        if (m_simulationLoopRunning)
+        // Request next frame if we are still running and if Qt3D is driving
+        // the loop
+        if (m_simulationLoopRunning && m_driveMode == QAspectEngine::Automatic)
             requestNextFrame();
     }
 
diff --git a/src/core/aspects/qaspectmanager_p.h b/src/core/aspects/qaspectmanager_p.h
index 1c07ab797..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();
 
@@ -90,6 +92,7 @@ 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);
@@ -104,7 +107,6 @@ public:
 private:
     bool event(QEvent *event) override;
     void requestNextFrame();
-    void processFrame();
 
     QVector<QAbstractAspect *> m_aspects;
     QEntity *m_root;
@@ -115,6 +117,7 @@ private:
     QScopedPointer<QServiceLocator> m_serviceLocator;
     bool m_mainLoopRunning;
     bool m_simulationLoopRunning;
+    QAspectEngine::RunMode m_driveMode;
 
 };