Crash when adding and removing entities in Qt3D - qt

Question

I have entities that should be created and deleted at runtime. Entity have only material and mesh component. Material is QDiffuseMapMaterial with QTextureImage.
When entities begin to add and delete from scene, sometimes application crashes with this assert:
qt_assert: ASSERT: "img != nullptr" in file
../../include/Qt3DRender/5.8.0/Qt3DRender/private/../../../../../src/render/texture/apitexturemanager_p.h,
line 286
But unfortunately I can’t figure out why it happenes. I’m adding the entity this way:
QEntity * visibleObject = new QEntity();
QDiffuseMapMaterial * material = new QDiffuseMapMaterial();
QTextureImage * diffuseTextureImage = new QTextureImage();
diffuseTextureImage->setSource(QUrl("qrc:/resources/tile.png"));
material->diffuse()->addTextureImage(diffuseTextureImage);
visibleObject->addComponent(material);
// set mesh
QPlaneMesh * mesh = new QPlaneMesh();
mesh->setWidth(1.0 / 2);
mesh->setHeight(1.0 / 2);
visibleObject->addComponent(mesh);
visibleObject->setParent(_rootEntity);
And delete just like this:
delete visibleObject;
_rootEntity is scene root entity defined in cpp code. Scene defined in QML file using Scene3D:
Scene3D {
id: scene
anchors.fill: parent
aspects: ["render", "logic", "input"]
entity: rootEntity
}
And _rootEntity passed like this:
context->setContextProperty("rootEntity", _rootEntity);
If it is necessary I can prepare simple example that reproduce issue.
Thanks.

Answer 1

The line visibleObject->setParent(_rootEntity); means that _rootEntity takes ownership of visibleObject. If you delete visibleObject; you create a dangling pointer in _rootEntity. See http://doc.qt.io/qt-5/objecttrees.html. So don't delete visibleObject;

Answer 2

It seems your trouble is that you've defining how to delete things incorrectly, The best solution to any problem is to eliminate the problem entirely.
Have you attempted to use smart pointers? Specifically Shared pointers? Using smart pointers eliminates the issue of hanging references entirely, and there is little if any overhead associated with their use. Qt even has it's own dedicated implementation of smart pointers.
If you eliminate the necessity to explicitly specify the deletion of your objects, you wouldn't have issues specifying the deletion.