Add private API to access child nodes of QEntity and QFrameGraphNode

This opens up for reduced bookeeping on the backend,
and is used by the experimental Dragon render aspect,
which is currently being implemented in qt3d-runtime.

Change-Id: I4cc2e98e4e0e7e8d456ed11c4fbc48db5c93f2a2
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>
(cherry picked from commit 77e418fde850c86e39d9dd8528876599fbe9dc34)
Reviewed-by: Mike Krus <mike.krus@kdab.com>
Reviewed-by: Christian Stromme <christian.stromme@qt.io>

1 files changed, 36 insertions, 10 deletions

diff --git a/tests/auto/core/qentity/tst_qentity.cpp b/tests/auto/core/qentity/tst_qentity.cpp
index efebb26ef..e27cd1fc9 100644
--- a/tests/auto/core/qentity/tst_qentity.cpp
+++ b/tests/auto/core/qentity/tst_qentity.cpp
@@ -556,30 +556,55 @@ void tst_Entity::removeSeveralTimesSameComponent()
 void tst_Entity::checkCloning_data()
 {
     QTest::addColumn<Qt3DCore::QEntity *>("entity");
+    QTest::addColumn<QVector<QNodeId>>("childEntityIds");
+    QTest::addColumn<int>("creationChangeCount");
 
-    QTest::newRow("defaultConstructed") << new MyEntity();
+    {
+        QTest::newRow("defaultConstructed") << new MyEntity() << QVector<QNodeId>() << 1;
+    }
+
+    {
+        Qt3DCore::QEntity *entityWithComponents = new MyEntity();
+        Qt3DCore::QComponent *component1 = new MyQComponent();
+        Qt3DCore::QComponent *component2 = new MyQComponent();
+        Qt3DCore::QComponent *component3 = new MyQComponent();
+        entityWithComponents->addComponent(component1);
+        entityWithComponents->addComponent(component2);
+        entityWithComponents->addComponent(component3);
+        QTest::newRow("entityWithComponents") << entityWithComponents << QVector<QNodeId>() << 4;
+    }
 
-    Qt3DCore::QEntity *entityWithComponents = new MyEntity();
-    Qt3DCore::QComponent *component1 = new MyQComponent();
-    Qt3DCore::QComponent *component2 = new MyQComponent();
-    Qt3DCore::QComponent *component3 = new MyQComponent();
-    entityWithComponents->addComponent(component1);
-    entityWithComponents->addComponent(component2);
-    entityWithComponents->addComponent(component3);
-    QTest::newRow("entityWithComponents") << entityWithComponents;
+    {
+        Qt3DCore::QEntity *entityWithChildren = new MyEntity();
+        Qt3DCore::QEntity *child1 = new MyEntity(entityWithChildren);
+        Qt3DCore::QEntity *child2 = new MyEntity(entityWithChildren);
+        QVector<QNodeId> childIds = {child1->id(), child2->id()};
+        QTest::newRow("entityWithChildren") << entityWithChildren << childIds << 3;
+    }
+
+    {
+        Qt3DCore::QEntity *entityWithNestedChildren = new MyEntity();
+        Qt3DCore::QEntity *child = new MyEntity(entityWithNestedChildren);
+        Qt3DCore::QNode *dummy = new Qt3DCore::QNode(entityWithNestedChildren);
+        Qt3DCore::QEntity *grandChild = new MyEntity(entityWithNestedChildren);
+        QVector<QNodeId> childIds = {child->id(), grandChild->id()};
+        QTest::newRow("entityWithNestedChildren") << entityWithNestedChildren << childIds << 4;
+    }
 }
 
 void tst_Entity::checkCloning()
 {
     // GIVEN
     QFETCH(Qt3DCore::QEntity *, entity);
+    QFETCH(QVector<QNodeId>, childEntityIds);
+    QFETCH(int, creationChangeCount);
 
     // WHEN
     Qt3DCore::QNodeCreatedChangeGenerator creationChangeGenerator(entity);
     QVector<Qt3DCore::QNodeCreatedChangeBasePtr> creationChanges = creationChangeGenerator.creationChanges();
 
     // THEN
-    QCOMPARE(creationChanges.size(), 1 + entity->components().size());
+    QCOMPARE(creationChanges.size(), creationChangeCount);
 
     const Qt3DCore::QNodeCreatedChangePtr<Qt3DCore::QEntityData> creationChangeData =
             qSharedPointerCast<Qt3DCore::QNodeCreatedChange<Qt3DCore::QEntityData>>(creationChanges.first());
@@ -591,6 +616,7 @@ void tst_Entity::checkCloning()
     QCOMPARE(creationChangeData->metaObject(), entity->metaObject());
     QCOMPARE(creationChangeData->parentId(), entity->parentNode() ? entity->parentNode()->id() : Qt3DCore::QNodeId());
     QCOMPARE(cloneData.parentEntityId, entity->parentEntity() ? entity->parentEntity()->id() : Qt3DCore::QNodeId());
+    QCOMPARE(cloneData.childEntityIds, childEntityIds);
     QCOMPARE(cloneData.componentIdsAndTypes.size(), entity->components().size());
 
     const QVector<Qt3DCore::QComponent *> &components = entity->components();