4 files changed, 74 insertions, 0 deletions
diff --git a/src/core/nodes/qbackendnode.cpp b/src/core/nodes/qbackendnode.cpp
index dc751cb93..65d140067 100644
--- a/src/core/nodes/qbackendnode.cpp
+++ b/src/core/nodes/qbackendnode.cpp
@@ -42,6 +42,7 @@
 
 #include <Qt3DCore/qaspectengine.h>
 #include <Qt3DCore/qnode.h>
+#include <Qt3DCore/qnodecommand.h>
 #include <Qt3DCore/qpropertyupdatedchange.h>
 
 #include <Qt3DCore/private/corelogging_p.h>
@@ -206,6 +207,25 @@ void QBackendNode::notifyObservers(const QSceneChangePtr &e)
     d->notifyObservers(e);
 }
 
+QNodeCommand::CommandId QBackendNode::sendCommand(const QString &name,
+                                                  const QVariant &data,
+                                                  QNodeCommand::CommandId replyTo)
+{
+    auto e = QNodeCommandPtr::create(peerId());
+    e->setName(name);
+    e->setData(data);
+    e->setReplyToCommandId(replyTo);
+    e->setDeliveryFlags(QSceneChange::Nodes);
+    notifyObservers(e);
+    return e->commandId();
+}
+
+void QBackendNode::sendReply(const QNodeCommandPtr &command)
+{
+    command->setDeliveryFlags(QSceneChange::Nodes);
+    notifyObservers(command);
+}
+
 void QBackendNode::initializeFromPeer(const QNodeCreatedChangeBasePtr &change)
 {
     Q_UNUSED(change);
diff --git a/src/core/nodes/qbackendnode.h b/src/core/nodes/qbackendnode.h
index d2cae5696..99e483cff 100644
--- a/src/core/nodes/qbackendnode.h
+++ b/src/core/nodes/qbackendnode.h
@@ -42,6 +42,7 @@
 
 #include <Qt3DCore/qnodecreatedchange.h>
 #include <Qt3DCore/qnodeid.h>
+#include <Qt3DCore/qnodecommand.h>
 #include <Qt3DCore/qscenechange.h>
 #include <Qt3DCore/qt3dcore_global.h>
 
@@ -90,6 +91,9 @@ protected:
     Q_DECLARE_PRIVATE(QBackendNode)
     explicit QBackendNode(QBackendNodePrivate &dd);
     void notifyObservers(const QSceneChangePtr &e);
+    QNodeCommand::CommandId sendCommand(const QString &name, const QVariant &data,
+                                        QNodeCommand::CommandId replyTo = QNodeCommand::CommandId());
+    void sendReply(const QNodeCommandPtr &command);
     virtual void sceneChangeEvent(const QSceneChangePtr &e);
 
     QBackendNodePrivate *d_ptr;
diff --git a/src/core/nodes/qnode.cpp b/src/core/nodes/qnode.cpp
index ce5e76a55..58e016cda 100644
--- a/src/core/nodes/qnode.cpp
+++ b/src/core/nodes/qnode.cpp
@@ -902,6 +902,51 @@ QNodeCreatedChangeBasePtr QNode::createNodeCreationChange() const
     return QNodeCreatedChangeBasePtr::create(this);
 }
 
+/*!
+ * \brief Sends a command messages to the backend node
+ *
+ * Creates a QNodeCommand message and dispatches it to the backend node. The
+ * command is given and a \a name and some \a data which can be used in the
+ * backend node to performe various operations.
+ * This returns a CommandId which can be used to identify the initial command
+ * when receiving a message in reply. If the command message is to be sent in
+ * reply to another command, \a replyTo contains the id of that command.
+ *
+ * \sa QNodeCommand, QNode::sendReply
+ */
+QNodeCommand::CommandId QNode::sendCommand(const QString &name,
+                                           const QVariant &data,
+                                           QNodeCommand::CommandId replyTo)
+{
+    Q_D(QNode);
+
+    // Bail out early if we can to avoid operator new
+    if (d->m_blockNotifications)
+        return QNodeCommand::CommandId(0);
+
+    auto e = QNodeCommandPtr::create(d->m_id);
+    e->setName(name);
+    e->setData(data);
+    e->setReplyToCommandId(replyTo);
+    d->notifyObservers(e);
+    return e->commandId();
+}
+
+/*!
+ * \brief Send a command back to the backend node
+ *
+ * Assumes the command is to be to sent back in reply to itself to the backend node
+ *
+ * \sa QNodeCommand, QNode::sendCommand
+ */
+void QNode::sendReply(const QNodeCommandPtr &command)
+{
+    Q_D(QNode);
+    command->setDeliveryFlags(QSceneChange::BackendNodes);
+    d->notifyObservers(command);
+}
+
+
 namespace {
 
 /*! \internal */
diff --git a/src/core/nodes/qnode.h b/src/core/nodes/qnode.h
index cf3a16301..1fe03f5e0 100644
--- a/src/core/nodes/qnode.h
+++ b/src/core/nodes/qnode.h
@@ -42,6 +42,7 @@
 
 #include <Qt3DCore/qnodecreatedchange.h>
 #include <Qt3DCore/qnodeid.h>
+#include <Qt3DCore/qnodecommand.h>
 #include <Qt3DCore/qscenechange.h>
 #include <Qt3DCore/qt3dcore_global.h>
 #include <QtCore/QObject>
@@ -98,6 +99,10 @@ public:
     void clearPropertyTracking(const QString &propertyName);
     void clearPropertyTrackings();
 
+    QNodeCommand::CommandId sendCommand(const QString &name, const QVariant &data = QVariant(),
+                                        QNodeCommand::CommandId replyTo = QNodeCommand::CommandId());
+    void sendReply(const QNodeCommandPtr &command);
+
 public Q_SLOTS:
     void setParent(QNode *parent);
     void setEnabled(bool isEnabled);