canto/Assets/Scripts/Entity/MotorAnimator.cs

using System.Threading;
using KitsuneCafe.Extension;
using KitsuneCafe.Sys;
using R3;
using UnityEngine;
using UnityForge.PropertyDrawers;

namespace KitsuneCafe.Entities
{
  public class MotorAnimator : MonoBehaviour
  {
    private const float epsilon = 0.05f;

    [Header("Dependencies")]
    [SerializeField]
    private Animator animator;

    [SerializeField]
    private new Rigidbody rigidbody;

    [SerializeField]
    private Spring spring;

    [SerializeField]
    private Motor motor;

    [SerializeField]
    private AirMotor airMotor;

    [SerializeField]
    private SprintFeature sprint;

    [Header("Movement")]
    [SerializeField, AnimatorParameterName(AnimatorControllerParameterType.Float, "animator")]
    private string movementSpeedParameter;

    [SerializeField]
    private float movementSmoothTime = 0.1f;

    [SerializeField, AnimatorParameterName(AnimatorControllerParameterType.Bool, "animator")]
    private string sprintingParameter;

    [SerializeField, Range(0f, 1f)]
    private float walkAnimationParamMax = 0.5f;

    [SerializeField, Range(0f, 1f)]
    private float sprintAnimationParamMax = 1.0f;

    [SerializeField, AnimatorParameterName(AnimatorControllerParameterType.Bool, "animator")]
    private string fallParam;

    [SerializeField, AnimatorParameterName(AnimatorControllerParameterType.Bool, "animator")]
    private string hardLandingParam;

    private CancellationTokenSource disableCancellationTokenSource;
    private CancellationToken disableCancellationToken => disableCancellationTokenSource.Token;

    private void Reset()
    {
      TryGetComponent(out animator);
      TryGetComponent(out rigidbody);
      TryGetComponent(out spring);
      TryGetComponent(out motor);
      TryGetComponent(out airMotor);
      TryGetComponent(out sprint);
    }

    private void OnEnable()
    {
      disableCancellationTokenSource = new();

      var d = Disposable.CreateBuilder();

      CurrentSpeed()
          .Compose(CurrentAnimationSpeed)
          .SmoothDamp(
              () => animator.GetFloat(movementSpeedParameter),
              movementSmoothTime,
              UnityTimeProvider.FixedUpdate
          )
          .Subscribe(speed =>
          {
            animator.SetFloat(movementSpeedParameter, speed);
          })
          .AddTo(ref d);

      sprint.IsSprinting
          .DistinctUntilChanged()
          .Subscribe(isSprinting =>
          {
            animator.SetBool(sprintingParameter, isSprinting);
          })
          .AddTo(ref d);


      Observable.FromEventHandler<LandingForce>(
          e => airMotor.Landed += e,
          e => airMotor.Landed -= e
      )
          .Select(eh => eh.e)
          .Where(force => force == LandingForce.Hard)
          .Subscribe(force => animator.SetTrigger(hardLandingParam))
          .AddTo(ref d);

      airMotor.ObservePropertyChanged(x => x.IsFalling)
        .Subscribe(falling => animator.SetBool(fallParam, falling))
        .AddTo(ref d);

      d.RegisterTo(disableCancellationToken);
    }

    private void OnDisable()
    {
      disableCancellationTokenSource.Cancel();
    }

    private Observable<float> CurrentSpeed() =>
        CurrentVelocity()
        .Select(vel => vel.sqrMagnitude)
        .DistinctUntilChanged()
        .Select(Mathf.Sqrt);

    private Observable<Vector3> CurrentVelocity() =>
      Observable.EveryUpdate(UnityFrameProvider.FixedUpdate)
        .Select(_ => rigidbody.linearVelocity);

    private Observable<float> CurrentAnimationSpeed(Observable<float> speedSource) =>
      speedSource
        .CombineLatest(motor.MaxSpeedSource, AnimationScaleFactor(), NormalizeSpeed)
        .DistinctUntilChanged(FEqualityComparer<float>.Create(KMath.IsApproxEqual));

    private Observable<float> AnimationScaleFactor() =>
      motor.MaxSpeedSource.Select(
        maxSpeed => NormalizationFactor(maxSpeed, motor.DefaultMaxSpeed)
      );

    private float NormalizationFactor(float maxSpeed, float defaultMaxSpeed) =>
      maxSpeed > defaultMaxSpeed ? sprintAnimationParamMax : walkAnimationParamMax;

    private float NormalizeSpeed(float currentSpeed, float maxSpeed, float factor) =>
      currentSpeed > maxSpeed && maxSpeed > epsilon ?
        factor :
        Mathf.InverseLerp(0, maxSpeed, currentSpeed) * factor;
  }
}