Global Blackboard from script?

[rixter757Participant]

Hi Gav,

Likely a newbie question. Here’s my code:

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using UnityEngine; using System.Collections; using System.Collections.Generic; using NodeCanvas.Framework;   public class FieldManager : MonoBehaviour { public Blackboard blackboard; public Vector3 myPos; void Start () { myPos = blackboard.GetValue<Vector3>("myPosition");

I am getting the error “Object reference not set to an instance of an object”. I don’t get it, surely myPos doesn’t need to be a reference to an object when I only want to assign a value to it from a Blackboard variable?

This is the code you posted for me in a thread below. I also did see a similar question where you advise GetComponent<Blackboard>() so I’m confused what is needed here.

Another point is that this is my Global Blackboard. The above code likely references the local?

Thanks,

Rix

[GavalakisKeymaster]

Hey,

The null reference is because the blackboard is not assigned a reference. Try this code bellow and please make sure that this script is attached to a gameobject that has a Blackboard component attached as well, since we assign the reference by GetComponent from this gameobject.

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using UnityEngine; using System.Collections; using System.Collections.Generic; using NodeCanvas.Framework; public class FieldManager : MonoBehaviour { public Blackboard blackboard; public Vector3 myPos; void Start () { blackboard = GetComponent<Blackboard>(); myPos = blackboard.GetValue<Vector3>("myPosition"); } }

Let me know if this works for you.
Cheers!

[rixter757Participant]

Hi Gav,

Yes this works well for the local Blackboard, thank you.

For information, how would I go about accessing the Global Blackboard?

Rix

[GavalakisKeymaster]

Hey,

Sure 🙂
You can get the reference of a global blackboard with the static method GlobalBlackboard.Find(string name), where the parameter is the blackboard name. Here is an example:

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public class Example : MonoBehaviour{   void Start(){ var bb = GlobalBlackboard.Find("Global"); var myPos = bb.GetValue<Vector3>("myPosition"); Debug.Log(myPos); } }

Let me know if this works for you.
Thanks.

[Author]

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