Add QmlEngine contructor parameter to Scene2D

Change-Id: I841f4f8e516d6b3656ed2dbc9ee694d25b4be78f
Reviewed-by: Tomi Korpipää <tomi.korpipaa@qt.io>
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

3 files changed, 55 insertions, 4 deletions

diff --git a/src/quick3d/quick3drender/scene2d/qscene2d.cpp b/src/quick3d/quick3drender/scene2d/qscene2d.cpp
index a1f84a929..f83cd3e4f 100644
--- a/src/quick3d/quick3drender/scene2d/qscene2d.cpp
+++ b/src/quick3d/quick3drender/scene2d/qscene2d.cpp
@@ -236,6 +236,7 @@ Scene2DManager::Scene2DManager(QScene2DPrivate *priv)
     , m_backendInitialized(false)
     , m_noSourceMode(false)
     , m_item(nullptr)
+    , m_ownEngine(false)
 {
     m_sharedObject->m_surface = new QOffscreenSurface;
     m_sharedObject->m_surface->setFormat(QSurfaceFormat::defaultFormat());
@@ -288,11 +289,16 @@ void Scene2DManager::startIfInitialized()
     if (!m_initialized && m_backendInitialized) {
         if (m_source.isValid() && !m_noSourceMode) {
             // Create a QML engine.
-            m_qmlEngine = new QQmlEngine;
-            if (!m_qmlEngine->incubationController())
-                m_qmlEngine->setIncubationController(m_sharedObject->m_quickWindow->incubationController());
+            if (!m_qmlEngine) {
+                m_qmlEngine = new QQmlEngine;
+                if (!m_qmlEngine->incubationController()) {
+                    m_qmlEngine->setIncubationController(m_sharedObject->m_quickWindow
+                                                         ->incubationController());
+                }
+            }
 
             // create component
+            m_ownEngine = true;
             m_qmlComponent = new QQmlComponent(m_qmlEngine, m_source);
             if (m_qmlComponent->isLoading()) {
                 connect(m_qmlComponent, &QQmlComponent::statusChanged,
@@ -322,7 +328,10 @@ void Scene2DManager::stopAndClean()
         m_sharedObject->requestQuit();
         m_sharedObject->wait();
         m_sharedObject->cleanup();
-        delete m_qmlEngine;
+        if (m_ownEngine) {
+            QObject::disconnect(m_connection);
+            delete m_qmlEngine;
+        }
         delete m_qmlComponent;
         m_qmlEngine = nullptr;
         m_qmlComponent = nullptr;
@@ -488,6 +497,23 @@ void Scene2DManager::cleanup()
     stopAndClean();
 }
 
+void Scene2DManager::setEngine(QQmlEngine *engine)
+{
+    m_qmlEngine = engine;
+    m_ownEngine = false;
+    if (engine) {
+        m_connection = QObject::connect(engine, &QObject::destroyed,
+                                        this, &Scene2DManager::engineDestroyed);
+    }
+}
+
+void Scene2DManager::engineDestroyed()
+{
+    QObject::disconnect(m_connection);
+    m_qmlEngine = nullptr;
+    m_ownEngine = false;
+}
+
 
 QScene2DPrivate::QScene2DPrivate()
     : Qt3DCore::QNodePrivate()
@@ -514,6 +540,15 @@ QScene2D::QScene2D(Qt3DCore::QNode *parent)
             this, &QScene2D::sourceLoaded);
 }
 
+QScene2D::QScene2D(QQmlEngine *engine, Qt3DCore::QNode *parent)
+    : Qt3DCore::QNode(*new QScene2DPrivate, parent)
+{
+    Q_D(QScene2D);
+    connect(d->m_renderManager, &Scene2DManager::onLoadedChanged,
+            this, &QScene2D::sourceLoaded);
+    d->m_renderManager->setEngine(engine);
+}
+
 QScene2D::~QScene2D()
 {
 }
@@ -638,6 +673,15 @@ bool QScene2D::event(QEvent *event)
 }
 
 /*!
+    Returns the qml engine used by the QScene2D.
+ */
+QQmlEngine *QScene2D::engine() const
+{
+    Q_D(const QScene2D);
+    return d->m_renderManager->m_qmlEngine;
+}
+
+/*!
     \internal
  */
 void QScene2D::sourceLoaded()
diff --git a/src/quick3d/quick3drender/scene2d/qscene2d.h b/src/quick3d/quick3drender/scene2d/qscene2d.h
index 67871f161..77ad6ea86 100644
--- a/src/quick3d/quick3drender/scene2d/qscene2d.h
+++ b/src/quick3d/quick3drender/scene2d/qscene2d.h
@@ -69,6 +69,7 @@ class QT3DQUICKRENDERSHARED_EXPORT QScene2D : public Qt3DCore::QNode
 
 public:
     explicit QScene2D(Qt3DCore::QNode *parent = nullptr);
+    QScene2D(QQmlEngine *engine, Qt3DCore::QNode *parent = nullptr);
     ~QScene2D();
 
     Qt3DRender::QRenderTargetOutput *output() const;
@@ -76,7 +77,9 @@ public:
     bool loaded() const;
     bool renderOnce() const;
     QQuickItem *item() const;
+    QQmlEngine *engine() const;
     bool event(QEvent *event) Q_DECL_OVERRIDE;
+
 public Q_SLOTS:
     void setOutput(Qt3DRender::QRenderTargetOutput *output);
     void setSource(const QUrl &url);
diff --git a/src/quick3d/quick3drender/scene2d/qscene2d_p.h b/src/quick3d/quick3drender/scene2d/qscene2d_p.h
index fbc19a42f..95f32f7c9 100644
--- a/src/quick3d/quick3drender/scene2d/qscene2d_p.h
+++ b/src/quick3d/quick3drender/scene2d/qscene2d_p.h
@@ -178,6 +178,7 @@ public:
 
     QUrl m_source;
     Qt3DCore::QNodeId m_id;
+    QMetaObject::Connection m_connection;
 
     bool m_requested;
     bool m_initialized;
@@ -185,6 +186,7 @@ public:
     bool m_renderOnce;
     bool m_backendInitialized;
     bool m_noSourceMode;
+    bool m_ownEngine;
 
     void requestRender();
     void requestRenderSync();
@@ -203,6 +205,8 @@ public:
     Q_SIGNAL void onLoadedChanged();
 
     void cleanup();
+    void setEngine(QQmlEngine *engine);
+    void engineDestroyed();
 };
 
 } // namespace Quick