Performance improvement by batching agent behavior tree update

[Noxalus]

Hello everyone,

We are working on a tycoon game with ~200 active agents at the same time, and we would like to reduce the cost of AI logic by splitting their execution over multiple frames.

Here is the code I would like to write:

public class AIManager : MonoBehaviour
{
    // List of all agents present in the game currently
    private List<Agent> _agents = new List<Agent>();
    private Queue<Agent> _agentsToExecute = new Queue<Agent>();

    private void Update()
    {
        if (!_agentsToExecute.Any())
        {
            _agents.ForEach(agent => _agentsToExecute.Enqueue(agent));
        }

        for (int i = 0; i < 20; i++)
        {
            var agent = _agentsToExecute.Dequeue();

            if (agent != null)
            {
                agent.BehaviorTree.Execute();
            }
        }
    }
}

There is no "Execute" method for the "BehaviorTree" class, but it's what I need to take the lead over the "BehaviorManager".

So my question: there is a way to do what I want without updating the Behavior Designer code?

Is that a good idea to reduce the performance cost of AI or it's a little bit dangerous? (maybe behavior trees expect to be executed each frame?)

Thanks in advance for your help!

 

[Justin]

So my question: there is a way to do what I want without updating the Behavior Designer code?

Yes, you can change the Behavior Manager update type to manual and call tick. See this page:

Behavior Manager - Opsive

When a behavior tree runs it creates a new GameObject with a Behavior Manager component if it isn’t already created. This component manages the execution . . .

opsive.com

Is that a good idea to reduce the performance cost of AI or it's a little bit dangerous?

That method is no problem and makes sense if you don't need to tick every frame.

 

[Noxalus]

Thank you very much for your answer, and sorry for not reading the documentation properly.

So from what I see, the code above should looks like that:

public class AIManager : MonoBehaviour
{
    // List of all agents present in the game currently
    private List<Agent> _agents = new List<Agent>();
    private Queue<Agent> _agentsToExecute = new Queue<Agent>();

    private void Update()
    {
        if (!_agentsToExecute.Any())
        {
            _agents.ForEach(agent => _agentsToExecute.Enqueue(agent));
        }

        for (int i = 0; i < 20; i++)
        {
            var agent = _agentsToExecute.Dequeue();

            if (agent != null)
            {
                BehaviorManager.instance.Tick(agent.BehaviorTree);
            }
        }
    }
}

I will try that, thank you again!