GetChild() not finding a node located in root?

In main.cpp i have
Node* ConeNode = GetScene()->CreateChild("ConeMan")
And it creates a Node, correctly named node. But when I try to do GetScene()->GetChild("ConeMan") in the Start() of a component it instead returns null and crashed later when I try to access the nonexistent node.
Instead of trying to search for it I simply passed a reference to the component and it didn’t crash, so the problem definitely isn’t with creation
Why isn’t it finding my correctly named node?

Are you sure you’re looking at the same Scene?

The component calling the GetChild() is attached to and controls the camera, and I can see the cone in the world, so I’m sure it’s the correct scene. I’m using the 1.7 release, so maybe it’s an old bug fixed in master?

Unlikely, although it would be wiser to use the latest master branch.
Could you share some more code?

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Creating/Loading scene
MainScene = new Scene(GetContext()); MainScene->LoadXML(Cache->GetResource<XMLFile>("Scenes/Help.xml")->GetRoot());

Start() of Component

void CameraComponent::Start() {
SubscribeToEvent(E_UPDATE, URHO3D_HANDLER(CameraComponent, HandleUpdate));

MainNode = GetNode();
MainCamera = MainNode->GetComponent<Camera>();
//ConeMan = GetScene()->GetChild("ConeMan"); <--- problem here
}

Making the cone and component
Functions in a static class:

Node* Creators::MakeCamera(Scene* MainScene, Node* ConeMan) {
Node* CameraNode = MainScene->CreateChild("CameraNode");
Camera* MainCamera = CameraNode->CreateComponent<Camera>();
MainCamera->SetFarClip(2000.f);
//CameraNode->CreateComponent<CameraComponent>();
// Fix for GetChild()
CameraComponent* CamComp = (CameraComponent*)CameraNode->CreateComponent(CameraComponent::GetTypeStatic());
CamComp->ConeMan = ConeMan;
CameraNode->AddComponent(CamComp, 0U, Urho3D::REPLICATED);

return CameraNode;
};

.

Node* Creators::MakeCone(Scene * MainScene, Vector3 Position, Quaternion Rotation) {
ResourceCache* Cache = MainScene->GetSubsystem<ResourceCache>();

Node* ConeNode = MainScene->CreateChild("ConeMan");
ConeNode->SetPosition(Position);
ConeNode->SetRotation(Rotation);

StaticModel* ConeModel = ConeNode->CreateComponent<StaticModel>();
ConeModel->SetModel(Cache->GetResource<Model>("Models/Cone.mdl"));
ConeModel->SetMaterial(Cache->GetResource<Material>("Materials/StoneTiled.xml"));
ConeModel->SetCastShadows(true);

return ConeNode;
}

Code called in main.cpp

ConeNode = Creators::MakeCone(MainScene, Vector3(0.f, 1.f, 0.f));
CameraNode = Creators::MakeCamera(MainScene, ConeNode);

As you can see the scenes passed when making the nodes are the same, so I’m sure it’s a bug. I’ll move to master and see

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I think I located the problem: Start is called after creation of the component, but before it is assigned to a node. No node; no scene.
Try changing CameraComponent::Start() to CameraComponent::OnNodeSet(Node* node).

Btw, if you have your Creators inherit from Object it can GetSubsystems too and even be registered as a subsystem itself.

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Thanks for the reply!

One last note: I instead chose OnSceneSet(Scene* scene), because when it’s called it directly gives me the scene, removing the need for a GetScene() call. But if I simply override it, the program will crash when exiting/cleaning up, because it’s called during cleanup to set the scene as nullptr. Here’s the completely working code:

virtual void OnSceneSet(Scene* scene) override;

void CameraComponent::OnSceneSet(Scene* scene) {
	if(scene != nullptr)
		ConeMan = scene->GetChild("ConeMan");
}
2 Likes

I use DelayedStart, this one fires after reloads are complete, after everything is essentially ready in the scene, to do late initializing

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I personally prefer if (!scene) return; but indeed safety nets like that are required.