Extending Dani AI

Each node can be extended and custom coded to fit your AI’s design.

Observers

To create an Observer, derive from GenericObserver<T>, where T is your desired output type (e.g. float, int, bool, etc). The functions to override within the GenericObserver<T> are listed below in the following table.

Here’s an example of creating a custom Observer that measures the speed of a rigidbody:

using InitialPrefabs.DaniAI;
using UnityEngine;

public class SpeedObserver : GenericObserver<float> {

    private Rigidbody rigidbody;

    // Use this for initialization, like Unity's Start() call
    public override void OnStart() {
        rigidbody = GetComponent<Rigidbody>();
    }

    // Like Unity's Update() call
    public override float OnObserverUpdate() {
        return rigidbody.velocity.magnitude;
    }
}

Decisions

We will support overriding Decisions at a future date.

Conditions

To create a new Condition, derive from the GenericCondition<T> class, where T is the type of output for the Condition.

using InitialPrefabs.DaniAI;
using UnityEngine;

public class VelocityCondition : GenericCondition<Vector3> {
    public enum MoveType { Idle, IsMoving }
    public MoveType comparison;
 
    // Override this method to validate the observer's output.
    public override float CalculateLocalWeight () {
        var value = observer.Output;
  
        if (comparison == MoveType.Idle) {
            // If the magnitude is 0, return a 1, otherwise return a 0
            return value.magnitude == 0 ? 1 : 0;
        }
        else {
            // If the magnitude is greater than 0, return a 1, otherwise     
            // return a 0
            return value.magnitude > 0 ? 1 : 0;
        }
    }
}

Actions

To create a custom Action, derive from the Action class. See the table below to see which functions to override.

Here’s an example of an Action script that moves a GameObject containing a NavMeshAgent.

using InitialPrefabs.DaniAI;
using UnityEngine;
using UnityEngine.AI;

public class Move : Action {
    public Vector3 destination;
    private NavMeshAgent agent;

    // Use this for initialization, like Unity's Start() call
    public override void OnStart() {
        agent = GetComponent<NavMeshAgent>();
    }

    // Runs at the first frame the Action is active
    public override void OnActionStart() {
        agent.destination = destination;
        agent.isStopped = false;
    }

    // Runs every frame after OnActionStart()
    public override ActionState OnActionUpdate() {
        if (agent.remainingDistance <= agent.stoppingDistance) {
            return ActionState.Success;
        } else {
            return ActionState.Running;
        }
    }

    // Runs at the very last frame before the Action is disabled
    public override void OnActionEnd(ActionState state) {
        if (state == ActionState.Success) {
            Debug.Log("I've arrived!");
            agent.isStopped = true;
            agent.ResetPath();
        } else {
            Debug.Log("Couldn't reach my destination.");
        }
    }
}

Variables

To create a Variable of any type, simply create a class that derives from GenericVariable<T>, where T is the desired type you need. See the example below.

using InitialPrefabs.DaniAI;
using UnityEngine;
using UnityEngine.AI;

public class Vector3Variable : GenericVariable<Vector3> {
    // That's it!
}