How to invoke an action/event from visual scripting

Unity Engine
,
1

I have an EventManager monobehavior which listens for events invoked from a GameEntity monobehavior.

public class EventManager : MonoBehaviour
{


    // Start is called before the first frame update

    void OnEnable()
    {
        GameEntity.playerStateChanged += doStuff;

    }


    void doStuff()
    {

  
    }

The GameEntity action variable and invoke are defined this way:

public class GameEntity : MonoBehaviour
{
    public static event Action playerStateChanged;

    private void OnHit()
    {
   
            Game.playerData.hitpointCurrent -= 1;
            Debug.Log("Updating Player Data");
            playerStateChanged?.Invoke();
       
    }
}

This works fine but there are cases where I need to also invoke the event from a visual script component on the same object as the GameEntity.

Iā€™ve been looking through the documentation and the fuzzy search and it isnā€™t clear how to do this. Any advice?

Thank you.

2

Bolt/UVS does not support any kind of delegates natively. So you either code a custom event node or invoke a UVS Custom Event via code instead. Custom Events API is documented in the official docs.

3

How do I call a method of a component from UVS?

Sorry to keep asking you questions. There seems to be so much about bolt and visual scripting that isnā€™t documented. Iā€™m using the documentation here:
https://docs.unity3d.com/Packages/com.unity.visualscripting@1.6/manual/vs-developers-guide.html

Is that correct place?

4

Iā€™m doing a unit graph of This > Get Component > Invoke Monobehavior. Seems to work fine.

5

Iā€™m assuming the function you are invoking is just a public function that invokes your action?
Or is it the subscriber of your action that you are invoking?

Invoke Monobehaviour will wait a frame. If you have a reference to that object you can call that function directly and not wait a frame.

6

https://docs.unity3d.com/Packages/com.unity.visualscripting@1.6/manual/vs-events-reference.html#events-api

This is probably the easiest way of triggering logic in a graph from a C# script currently. Note that Ludiq and Bolt namespaces are migrated to Unity.VisualScripting, the docs are out of date. But the custom event API syntax should be identical.

7

Iā€™ve been hours and hours trying to work out the logic of triggering a custom event from a c# script to visual scripting (the one that is shown in your link), but I havenā€™t succeeded so far, even with the most basic scriptā€¦ so that makes me think that the API syntax has changed.

this is an example script that I used:

"
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Bolt;
using Ludiq;

public class RevertChanges : MonoBehaviour
{

void start()
{
CustomEvent.Trigger(enemy, ā€œDamageā€, 30);
}
}

"

and I got my Target Game Object (Enemy) already set up with its Custom Event (Damage) and everything.

These are the errors I keep getting:
(1)

Assets\Scripts\UI\RevertChanges.cs(4,7): error CS0246: The type or namespace name ā€˜Boltā€™ could not be found (are you missing a using directive or an assembly reference?)

(2)
Assets\Scripts\UI\RevertChanges.cs(5,7): error CS0246: The type or namespace name ā€˜Ludiqā€™ could not be found (are you missing a using directive or an assembly reference?)

Sometimes when I donā€™t get those errors I get the ā€œ,ā€ expected (in a line and ch: in front of the ā€œtarget game objectā€) that does not make sense, and when I arbitrarily change anything to make that error disappear I get the previous 2 errors back.

Does anyone by any chance know what on Earth is going on?

8

For any future wanderer, I found the solution:

The API was in fact changed (for visual scripting). The updated link is this one:
https://docs.unity3d.com/Packages/com.unity.visualscripting@1.8/manual/vs-events-reference.html#events-api

The solution in the example I used would be:
(1) to replace both (using Ludiq;, and using Bolt;) by (using Unity.VisualScripting;)
(2) make a reference to the game object in the inspector (public GameObject (name it as you want, in this case will be: public GameObject enemy;)

and now the ā€œCustomEvent.Trigger(enemy, ā€œDamageā€, 30);ā€ should trigger just fine

PS: Sorry for necro-ing the post, I was kind of desperate at this point. At least I hope this can find and help anyone who got into the same issue as me.

1 Like
9

I actually wrote a package for that: https://assetstore.unity.com/packages/tools/visual-scripting/bolt-unity-events-175821

Originally it was written for bolt and still depends on it. But due to the positive reviews I think my fix mentioned on the asset-page-itself solves the compiler-issues one should expect adding this to the project.