Allow to filter change events based on a track property

* QNode now has a PropertyTrackMode property
* QScene contains a table of PropertyTrakcMode data
* QPostman checks if a QNode is supposed to receive a change based on the
  information available in the QScene property track mode table
* Unit tests updated and added for QPostman

Change-Id: I3b88037a949020a917c81817f1451ef532065982
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

3 files changed, 90 insertions, 2 deletions

diff --git a/src/core/nodes/qnode.cpp b/src/core/nodes/qnode.cpp
index e4bb5d4a3..77d7c0a6b 100644
--- a/src/core/nodes/qnode.cpp
+++ b/src/core/nodes/qnode.cpp
@@ -73,6 +73,7 @@ QNodePrivate::QNodePrivate()
     , m_blockNotifications(false)
     , m_hasBackendNode(false)
     , m_enabled(true)
+    , m_propertyTrackMode(QNode::DefaultTrackMode)
     , m_propertyChangesSetup(false)
     , m_signals(this)
 {
@@ -402,7 +403,6 @@ void QNodePrivate::unsetSceneHelper(QNode *root)
                 m_scene->removeEntityForComponent(c->id(), entity->id());
         }
     }
-
     if (m_scene != nullptr)
         m_scene->removeObservable(root);
     root->d_func()->setScene(nullptr);
@@ -495,8 +495,13 @@ void QNode::sceneChangeEvent(const QSceneChangePtr &change)
  */
 void QNodePrivate::setScene(QScene *scene)
 {
-    if (m_scene != scene)
+    if (m_scene != scene) {
+        if (m_scene != nullptr)
+            m_scene->removePropertyTrackDataForNode(m_id);
         m_scene = scene;
+        // set PropertyTrackData in the scene
+        updatePropertyTrackMode();
+    }
 }
 
 /*!
@@ -580,6 +585,16 @@ void QNodePrivate::insertTree(QNode *treeRoot, int depth)
         treeRoot->setParent(q_func());
 }
 
+void QNodePrivate::updatePropertyTrackMode()
+{
+    if (m_scene != nullptr) {
+        QScene::NodePropertyTrackData trackData;
+        trackData.updateMode = m_propertyTrackMode;
+        trackData.namedProperties = m_trackedProperties;
+        m_scene->setPropertyTrackDataForNode(m_id,trackData);
+    }
+}
+
 /*!
     \internal
  */
@@ -769,6 +784,34 @@ void QNode::setEnabled(bool isEnabled)
     emit enabledChanged(isEnabled);
 }
 
+void QNode::setPropertyTrackMode(QNode::PropertyTrackMode mode)
+{
+    Q_D(QNode);
+    if (d->m_propertyTrackMode == mode)
+        return;
+
+    d->m_propertyTrackMode = mode;
+    // The backend doesn't care about such notification
+    const bool blocked = blockNotifications(true);
+    emit propertyUpdateModeChanged(mode);
+    blockNotifications(blocked);
+    d->updatePropertyTrackMode();
+}
+
+void QNode::setTrackedProperties(const QStringList &trackedProperties)
+{
+    Q_D(QNode);
+    if (d->m_trackedProperties == trackedProperties)
+        return;
+
+    d->m_trackedProperties = trackedProperties;
+    // The backend doesn't care about such notification
+    const bool blocked = blockNotifications(true);
+    emit trackedPropertiesChanged(trackedProperties);
+    blockNotifications(blocked);
+    d->updatePropertyTrackMode();
+}
+
 /*!
     \property Qt3DCore::QNode::enabled
 
@@ -785,6 +828,32 @@ bool QNode::isEnabled() const
     return d->m_enabled;
 }
 
+/*!
+    \property Qt3DCore::QNode::propertyTrackMode
+
+    Holds the property track mode which determines whether a QNode should
+    be listening for property updates
+
+    By default it is set to QNode::DontTrackProperties
+*/
+QNode::PropertyTrackMode QNode::propertyTrackMode() const
+{
+    Q_D(const QNode);
+    return d->m_propertyTrackMode;
+}
+
+/*!
+    \property Qt3DCore::QNode::trackedProperties
+
+    Holds the names of the properties to be tracked when propertyTrackMode is
+    set to TrackNamedProperties.
+*/
+QStringList QNode::trackedProperties() const
+{
+    Q_D(const QNode);
+    return d->m_trackedProperties;
+}
+
 QNodeCreatedChangeBasePtr QNode::createNodeCreationChange() const
 {
     // Uncomment this when implementing new frontend and backend types.
diff --git a/src/core/nodes/qnode.h b/src/core/nodes/qnode.h
index cadcc7d5c..75ea61cc7 100644
--- a/src/core/nodes/qnode.h
+++ b/src/core/nodes/qnode.h
@@ -69,7 +69,17 @@ class QT3DCORESHARED_EXPORT QNode : public QObject
     Q_OBJECT
     Q_PROPERTY(Qt3DCore::QNode *parent READ parentNode WRITE setParent NOTIFY parentChanged)
     Q_PROPERTY(bool enabled READ isEnabled WRITE setEnabled NOTIFY enabledChanged)
+    Q_PROPERTY(PropertyTrackMode propertyTrackMode READ propertyTrackMode WRITE setPropertyTrackMode NOTIFY propertyUpdateModeChanged)
+    Q_PROPERTY(QStringList trackedProperties READ trackedProperties WRITE setTrackedProperties NOTIFY trackedPropertiesChanged)
 public:
+
+    enum PropertyTrackMode {
+        DefaultTrackMode,
+        TrackNamedPropertiesMode,
+        TrackAllPropertiesMode
+    };
+    Q_ENUM(PropertyTrackMode)
+
     explicit QNode(QNode *parent = nullptr);
     virtual ~QNode();
 
@@ -82,14 +92,20 @@ public:
     QNodeVector childNodes() const;
 
     bool isEnabled() const;
+    PropertyTrackMode propertyTrackMode() const;
+    QStringList trackedProperties() const;
 
 public Q_SLOTS:
     void setParent(QNode *parent);
     void setEnabled(bool isEnabled);
+    void setPropertyTrackMode(PropertyTrackMode mode);
+    void setTrackedProperties(const QStringList &trackedProperties);
 
 Q_SIGNALS:
     void parentChanged(QObject *parent);
     void enabledChanged(bool enabled);
+    void propertyUpdateModeChanged(PropertyTrackMode mode);
+    void trackedPropertiesChanged(const QStringList &trackedProperties);
     void nodeDestroyed();
 
 protected:
diff --git a/src/core/nodes/qnode_p.h b/src/core/nodes/qnode_p.h
index a90011128..5d6329e62 100644
--- a/src/core/nodes/qnode_p.h
+++ b/src/core/nodes/qnode_p.h
@@ -84,6 +84,7 @@ public:
     void notifyObservers(const QSceneChangePtr &change) Q_DECL_OVERRIDE;
 
     void insertTree(QNode *treeRoot, int depth = 0);
+    void updatePropertyTrackMode();
 
     Q_DECLARE_PUBLIC(QNode)
 
@@ -97,6 +98,8 @@ public:
     bool m_blockNotifications;
     bool m_hasBackendNode;
     bool m_enabled;
+    QNode::PropertyTrackMode m_propertyTrackMode;
+    QStringList m_trackedProperties;
 
     static QNodePrivate *get(QNode *q);
     static void nodePtrDeleter(QNode *q);