Event callbacks are parameterless by default, but it can sometimes be useful to give them a parameter by setting one of the AnimancerEvent.Parameter... options as their Callback. This allows events to do things like specify which foot a footstep is referring to without needing to have a separate event name for each one as demonstrated in the Footstep Events sample.

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	Animancer supports common parameter types by default and you can easily create your own custom parameter types.

When registering a callback to receive a parameter, you must specify the parameter type as a generic argument with slightly different syntax depending on how you're setting up the events:

[SerializeField] private AnimancerComponent _Animancer;
[SerializeField] private ClipTransition _Animation;
[SerializeField] private StringAsset _EventName;

protected virtual void Awake()
{
    // Central Events.
    _Animancer.Events.AddTo<AudioSource>(_EventName, PlaySound);

    // Transition Events.
    _Animation.Events.AddCallback<AudioSource>(_EventName, PlaySound);

    // State Events.
    AnimancerState state = _Animancer.Play(_Animation);
    if (state.Events(this, out AnimancerEvent.Sequence events))
    {
        events.AddCallback<AudioSource>(_EventName, PlaySound);
    }
}

private void PlaySound(AudioSource source) { }

Custom Parameter Types

Serialized event callbacks are stored as classes that implement IInvokable:

• Animancer.UnityEvent inherits from UnityEngine.Events.UnityEvent to allow UnityEvents to be used as event callbacks.
• Animancer.UltEvent inherits from UltEvents.UltEvent to allow UltEvents to be used as event callbacks.
• AnimancerEvent.Parameter is the base class for objects which make a parameter value available to other callbacks registered for the same event.
  • AnimancerEvent.ParameterBoxed does the same thing for value type parameters (structs and enums).

So if you want to add another parameter type you can simply make a serializable class that inherits from the appropriate base parameter, for example:

[System.Serializable]
public class ParameterVector3 : Animancer.AnimancerEvent.ParameterBoxed<UnityEngine.Vector3> { }

Simply having that class in your project will allow you to select it when assigning event callbacks.

You could also implement IInvokable to directly make your own custom callback:

[System.Serializable]
public class Invokable : Animancer.IInvokable
{
    public virtual void Invoke()
    {
        // Do stuff.
    }
}