Custom Adapter

In LitMotion, IMotionAdapter<T, TOptions> and IMotionOptions interfaces are provided for extension purposes.

Implementing an Adapter

Implementing a structure that conforms to IMotionAdapter<T, TOptions> allows you to animate custom types. Below is an example of implementing Vector3MotionAdapter to add support for Vector3:

using Unity.Jobs;
using Unity.Mathematics;
using UnityEngine;
using LitMotion;

// The assembly attribute is necessary to support Burst for Jobs
// Add the RegisterGenericJobType attribute to register MotionUpdateJob<T, TOptions, TAdapter>
[assembly: RegisterGenericJobType(typeof(MotionUpdateJob<Vector3, NoOptions, Vector3MotionAdapter>))]

// Create a structure implementing IMotionAdapter with type arguments specifying the target value type and additional options (if required, else use NoOptions)
public readonly struct Vector3MotionAdapter : IMotionAdapter<Vector3, NoOptions>
{
    // Implement the interpolation logic within the Evaluate method
    public Vector3 Evaluate(ref Vector3 startValue, ref Vector3 endValue, ref NoOptions options, in MotionEvaluationContext context)
    {
        return Vector3.LerpUnclamped(startValue, endValue, context.Progress);
    }
}

Adapters cannot hold state, so refrain from defining unnecessary fields within them.

LitMotion utilizes generic Jobs internally. Therefore, when using custom types, you need to add the RegisterGenericJobType attribute to the assembly to ensure Burst recognizes the types.

If you want motions to have special states, implement an unmanaged structure conforming to IMotionOptions. Here is a partial implementation example for IntegerOptions used in motions involving int or long types:

public struct IntegerOptions : IMotionOptions, IEquatable<IntegerOptions>
{
    public RoundingMode RoundingMode;

    // Implement Equals, GetHashCode, etc.
    ...
}

Specify NoOptions if options are not necessary.

Creating Motions Using Custom Adapters

When creating a MotionBuilder with LMotion.Create, you can use a custom adapter by passing the adapter type as a type argument.

LMotion.Create<Vector3, NoOptions, Vector3MotionAdapter>(from, to, duration)
    .BindToPosition(transform);