RenderBuffer: handle the sync property

And update the frontend QBuffer with the data obtained from the functor
if sync is true.

Change-Id: I86e4dff50fedf3fbc6057843a8a60c978d68b047
Task-number: QTBUG-48454
Reviewed-by: Andy Nichols <andy.nichols@theqtcompany.com>

4 files changed, 28 insertions, 1 deletions

diff --git a/src/render/geometry/buffer.cpp b/src/render/geometry/buffer.cpp
index 762148182..0fdd258a1 100644
--- a/src/render/geometry/buffer.cpp
+++ b/src/render/geometry/buffer.cpp
@@ -36,6 +36,7 @@
 
 #include "buffer_p.h"
 #include <Qt3DCore/qscenepropertychange.h>
+#include <Qt3DCore/qbackendscenepropertychange.h>
 #include <Qt3DRenderer/private/buffermanager_p.h>
 
 QT_BEGIN_NAMESPACE
@@ -46,10 +47,11 @@ namespace Qt3DRender {
 namespace Render {
 
 Buffer::Buffer()
-    : QBackendNode(QBackendNode::ReadOnly)
+    : QBackendNode(QBackendNode::ReadWrite)
     , m_type(QBuffer::VertexBuffer)
     , m_usage(QBuffer::StaticDraw)
     , m_bufferDirty(false)
+    , m_sync(false)
     , m_manager(Q_NULLPTR)
 {
     // Maybe it could become read write if we want to inform
@@ -67,6 +69,7 @@ void Buffer::cleanup()
     m_data.clear();
     m_functor.reset();
     m_bufferDirty = false;
+    m_sync = false;
 }
 
 
@@ -79,6 +82,14 @@ void Buffer::executeFunctor()
 {
     Q_ASSERT(m_functor);
     m_data = (*m_functor)();
+    if (m_sync) {
+        // Send data back to the frontend
+        QBackendScenePropertyChangePtr e(new QBackendScenePropertyChange(NodeUpdated, peerUuid()));
+        e->setPropertyName("data");
+        e->setTargetNode(peerUuid());
+        e->setValue(QVariant::fromValue(m_data));
+        notifyObservers(e);
+    }
 }
 
 void Buffer::updateFromPeer(Qt3DCore::QNode *peer)
@@ -93,6 +104,7 @@ void Buffer::updateFromPeer(Qt3DCore::QNode *peer)
         if (m_functor && m_manager != Q_NULLPTR)
             m_manager->addDirtyBuffer(peerUuid());
         m_bufferDirty = true;
+        m_sync = buffer->isSync();
     }
 }
 
@@ -117,6 +129,8 @@ void Buffer::sceneChangeEvent(const Qt3DCore::QSceneChangePtr &e)
             m_functor = newFunctor;
             if (m_functor && m_manager != Q_NULLPTR)
                 m_manager->addDirtyBuffer(peerUuid());
+        } else if (propertyName == QByteArrayLiteral("sync")) {
+            m_sync = propertyChange->value().toBool();
         }
     }
 }
diff --git a/src/render/geometry/buffer_p.h b/src/render/geometry/buffer_p.h
index 1d5d02dae..7da08a2a2 100644
--- a/src/render/geometry/buffer_p.h
+++ b/src/render/geometry/buffer_p.h
@@ -78,6 +78,7 @@ public:
     inline QByteArray data() const { return m_data; }
     inline bool isDirty() const { return m_bufferDirty; }
     inline QBufferFunctorPtr bufferFunctor() const { return m_functor; }
+    inline bool isSync() const { return m_sync; }
     void unsetDirty();
 
 private:
@@ -85,6 +86,7 @@ private:
     QBuffer::UsageType m_usage;
     QByteArray m_data;
     bool m_bufferDirty;
+    bool m_sync;
     QBufferFunctorPtr m_functor;
     BufferManager *m_manager;
 };
diff --git a/src/render/geometry/qbuffer.cpp b/src/render/geometry/qbuffer.cpp
index 41c10e7e1..df789486b 100644
--- a/src/render/geometry/qbuffer.cpp
+++ b/src/render/geometry/qbuffer.cpp
@@ -87,6 +87,16 @@ void QBuffer::copy(const QNode *ref)
     d_func()->m_sync = buffer->d_func()->m_sync;
 }
 
+void QBuffer::sceneChangeEvent(const QSceneChangePtr &change)
+{
+    QScenePropertyChangePtr e = qSharedPointerCast<QScenePropertyChange>(change);
+    if (e->type() == NodeUpdated && e->propertyName() == QByteArrayLiteral("data")) {
+        const bool blocked = blockNotifications(true);
+        setData(e->value().toByteArray());
+        blockNotifications(blocked);
+    }
+}
+
 QBuffer::UsageType QBuffer::usage() const
 {
     Q_D(const QBuffer);
diff --git a/src/render/geometry/qbuffer.h b/src/render/geometry/qbuffer.h
index 186f236a6..c2da32fbe 100644
--- a/src/render/geometry/qbuffer.h
+++ b/src/render/geometry/qbuffer.h
@@ -103,6 +103,7 @@ public:
 protected:
     QBuffer(QBufferPrivate &dd, QBuffer::BufferType ty, Qt3DCore::QNode *parent = 0);
     void copy(const Qt3DCore::QNode *ref) Q_DECL_OVERRIDE;
+    void sceneChangeEvent(const Qt3DCore::QSceneChangePtr &change) Q_DECL_OVERRIDE;
 
 Q_SIGNALS:
     void typeChanged();