Unity Events + Scriptable Objects + Multiplayer - Game Architecture Question

News & General Discussion
1

Hi,

I have a question about how to organice my game.

I was studying the open project (chop chop) and really liked the way events are handled:
There they are useing scriptable objects as connecting objects.
Here is some simplyfied example code:
The InventorySO and the Item have the same ItemEventChannelSO
The Item OnTriggerEnter gets triggerd and invokes the RaiseEvent in the connecting ScriptableObject. The InventorySO subscriped to that “Event” and adds the Item to its Items-list.

public class InventorySO : ScriptableObject
{
    [Tooltip("The collection of items and their quantities.")]
    [SerializeField]
    private List<Item> _items = new List<Item>();

    public List<Item> Items => _items;

    public ItemEventChannelSO pickUpItem;

    private void OnEnable()
    {
       if (pickUpItem!= null)
        {
            pickUpItem +=  Add;
        }
    }
    private void OnDisable()
    {
       if (pickUpItem!= null)
        {
            pickUpItem -=  Add;
        }
    }
    public void Add(ItemSO item)
    {
        _items.Add(item);
    }
}

public class ItemEventChannelSO : ScriptableObject
{
    public UnityAction<Item> OnEventRaised;

    public void RaiseEvent(Item item)
    {
        if (OnEventRaised != null)
            OnEventRaised.Invoke(item);
    }
}

public class Item: Monobehaviour
{
 
  public ItemEventChannelSO pickUpItem;

  private void OnTriggerEnter([URL='https://docs.unity3d.com/ScriptReference/Collider.html']Collider[/URL] other)
   {
   
   pickUpItem?.RaiseEvent(this);
   }
 
}

I think it is a realy clever way to connect objects, but what I can’t figure out is, how to use such a system in a multiplayer envirnoment.
For example, if a game has 100 players does every player neet to have it’s own ItemEventChannelSO ScriptableObject?

I hope I formulated the question understandable, otherwise just let me know and I’ll adjust it.

2

Almost certainly yes. Those will be local, client-side objects.

3

So, this “design pattern” is only usable for singleplayer? What would be a good alternative for multiplayer?

4

You can adapt them to multiplayer. But the design pattern will only be a small part compared to the part that makes it work with multiplayer. I recommend making a few very small multiplayer prototypes first before thinking about design patterns. Just get the multiplayer working however you can. This will give you a deeper insight into how to implement this design pattern if you choose to.

5

thx for the tip, but it’s more of a general question if it’s possible to adapt the design pattern not about multiplayer. It would be the same problem if there are multiple characteres controlled by one player.
Do you think it’s possible to do with the scriptable object approach?

6

Using ScriptableObjects, or more likely you’re referring to ScriptableObject assets, is just one way of implementing the design pattern. It’s just an observer. If you have 100 local player characters, you can either create 100 objects at runtime or include the the player ID with the event. In either case, there’s probably no reason to use ScriptableObjects for them.