Archive 17/01/2023.

Regarding Children of Disabled Nodes

Leith

In the following snippet, we can see a Node that is Disabled, yet its children are still rendered - this is rather unexpected, is it deliberate?
If so, can I please have an example of a valid use-case for a child of something that is disabled to be processed at runtime, other than serializing / replicating it?

I’m simply trying to understand why the entire tree under a disabled node is not effectively being disabled too.

	<node id="5">
		<attribute name="Is Enabled" value="false" />
		<attribute name="Name" value="GamePlayState" />
		<attribute name="Tags" />
		<attribute name="Position" value="0 0 0" />
		<attribute name="Rotation" value="1 0 0 0" />
		<attribute name="Scale" value="1 1 1" />
		<attribute name="Variables" />
		<component type="GamePlayState" id="187" />
		<node id="8">
			<attribute name="Is Enabled" value="true" />
			<attribute name="Name" value="Mushroom" />
			<attribute name="Tags" />
			<attribute name="Position" value="11.4454 0 -89.7748" />
			<attribute name="Rotation" value="0.821201 0 0.570639 0" />
			<attribute name="Scale" value="6.0437 6.0437 6.0437" />
			<attribute name="Variables" />
			<component type="StaticModel" id="7">
				<attribute name="Model" value="Model;Models/Mushroom.mdl" />
				<attribute name="Material" value="Material;Materials/Mushroom.xml" />
				<attribute name="Cast Shadows" value="true" />
			</component>
			<component type="RigidBody" id="8">
				<attribute name="Physics Rotation" value="0.821201 0 0.570639 0" />
				<attribute name="Physics Position" value="11.4454 0 -89.7748" />
				<attribute name="Collision Layer" value="2" />
			</component>
			<component type="CollisionShape" id="9">
				<attribute name="Shape Type" value="TriangleMesh" />
				<attribute name="Model" value="Model;Models/Mushroom.mdl" />
			</component>
		</node>
Modanung

Have you seen the other functions regarding enabling and disabling Nodes?

Set enabled/disabled state without recursion. Components in a disabled node become effectively disabled regardless of their own enable/disable state.

void SetEnabled(bool enable);

Set enabled state on self and child nodes. Nodes’ own enabled state is remembered (IsEnabledSelf) and can be restored.

void SetDeepEnabled(bool enable);

Reset enabled state to the node’s remembered state prior to calling SetDeepEnabled.

void ResetDeepEnabled();

Set enabled state on self and child nodes. Unlike SetDeepEnabled this does not remember the nodes’ own enabled state, but overwrites it.

void SetEnabledRecursive(bool enable);

Leith

Thanks Modanung!
Yes I had noticed those, I just find it to be a strange design decision to fully recurse node hierarchies beyond any disabled node. I’m now forced to recursive disable all the child nodes, fair enough, I suspected that would work, I’m just curious why it works this way - this is certainly not common among the many scenegraphs I have encountered in the past. I wonder to myself: What was the thinking behind this design decision, to NOT take advantage of early-out during scene recursion?

Anyway, I ended up with the following arrangement in my test GamePlay gamestate implementation:

	/// node was attached to scene (also called on detach, with node=nullptr)
	virtual void OnNodeSet( Urho3D::Node* node ){
        if(node!=nullptr)
        {
            CreateScene();
            CreateUI();
            node->SetDeepEnabled(false);
        }
	}		

	/// entering gamestate
	virtual void Enter(){
        SubscribeToEvent(E_UPDATE, URHO3D_HANDLER(ClassName, OnUpdate));
        GetNode()->ResetDeepEnabled();
	}

	/// exiting gamestate
	virtual void Exit(){
        UnsubscribeFromEvent(E_UPDATE);
        GetNode()->SetDeepEnabled(false);
	}

This arrangement should be sufficient for my immediate needs. I have omitted code for resource management so we can just see the logic for enabling/disabling gamestates. I guess I can live with something like this.