Share Blackboard across Agents with same Behaviour Tree

[joncParticipant]

Hi, so I’m almost done creating a custom editor function that sets up a lot of agents at once at the press of a button. The only obstacle left is how to automatically populate a blackboard.

My NodeCanvas specific part in the “Setup Agents” editor script looks like this:

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BehaviourTreeOwner btOwner = agent.GetComponent<BehaviourTreeOwner>();         if(btOwner.graph == null)             btOwner.graph = Resources.Load("NodeCanvas BTs/Universal Agent BT") as BehaviourTree;

This also adds the BB but of course it’s empty.
Is there a way to save a BB preset and load it via code?

[GavalakisKeymaster]

Hello,

Hmm. There are two possible solutions that I can think of for this.

1) You can use the Blackboard API, to set the variables by code directly. For example:

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public void SetVariables(){ var bb = GetComponent<Blackboard>(); bb.SetValue("myFloat", 13f); bb.SetValue("myColor", Color.yellow); }

2) You could save a Blackboard variables to a serialized json string and store it somewhere, then deserialize the target blackboard you want, using that json. Some example code:

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public class Examples : MonoBehaviour {   public string blackboardPresetJson;   public void SaveToJson(){ var bb = GetComponent<Blackboard>(); blackboardPresetJson = bb.Serialize(); }   public void LoadFromJson(){ var bb = GetComponent<Blackboard>(); bb.Deserialize(blackboardPresetJson); } }

You could of course also create some editor utility to save the json string to a file in editor only, like for example:

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[ContextMenu("Save Attached Blackboard To Preset File")] public void SaveToFile(){ var bb = GetComponent<Blackboard>(); var path = EditorUtility.SaveFilePanelInProject("Save Preset", string.Empty, "bb", string.Empty); if (!string.IsNullOrEmpty(path)){ System.IO.File.WriteAllText( path, bb.Serialize() ); AssetDatabase.Refresh(); } }

Then in runtime you would need to of course have a reference to that saved TextAsset file and deserialize the blackboard from it’s contents. Once again, for example:

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public TextAsset presetFile;   public void LoadPreset(){ var bb = GetComponent<Blackboard>(); bb.Deserialize( presetFile.text ); }

Let me know if any of the above solutions works for you.

Thanks!

[joncParticipant]

Procedure 1 is exactly what I needed.
Procedure 2 is also nice in the long run. Thanks to your code above I’ll be able to set up a nice compfortable editor function soon.

Thanks for the help!

[GavalakisKeymaster]

You are very welcome 🙂
I am glad that I could help!

Thanks!

[joncParticipant]

Greetings Nuverian,

before starting another thread I ask this here…

So I open the graph via editor script like this:

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public static void EditBehaviourTree() {           Graph graph = Selection.activeTransform.root.GetComponent<BehaviourTreeOwner>().graph;           GraphEditor.OpenWindow(graph); }

This opens the Graph but not the Blackboard and all the node variables are gone or not loaded. How do I get the same behaviour as if I would click the “Edit Behaviour Tree” button on the inspector?

The reason I want to get this to work is that my agents are full of components and this would be a welcome shortcut. 🙂

[GavalakisKeymaster]

Hello again,

I am really sorry for the late reply. I got sick :/

There are a few overloads for the ‘OpenWindow’ method. If you have a Blackboard already attached on the BehaviourTreeOwner in question, you can then use the overload that takes a “GraphOwner” instead. This will load the owner’s graph as well as the owner’s blackboard together in the editor 🙂

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GraphEditor.OpenWindow( Selection.activeTransform.root.GetComponent<BehaviourTreeOwner>() );

Please let me know if that works for you.
Thanks!

[joncParticipant]

Hi, I hope you’re well again…

I really should start checking overloads more often. Doing it the way you described worked of course.

Thanks once more!

[GavalakisKeymaster]

You are very welcome! 🙂

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