Foot IK

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace AGD.Core.IK
{
    /// <summary>
    /// To be placed on a character in order to add a foot IK grounding behaviour
    /// Requires an Animator with a Layer set to IK Pass
    /// </summary>
    [RequireComponent(typeof(Animator))]
    public class FootIK : MonoBehaviour
    {
        private Animator _animator;

        [Tooltip("Set to false and this script won't run.")]
        [SerializeField] private bool applyFootIK = true;

        [Tooltip("Select the layer to which the foot IK will be applied")]
        [SerializeField] private LayerMask targetLayer;
        [Tooltip("the distance from the IK Foot Transform to the lowest point of the foot")]
        [Range(0,1)][SerializeField] private float distanceToGround = 0;


        private void Start()
        {
            _animator = GetComponent<Animator>();
        }

        private void OnAnimatorIK(int layerIndex)
        {
            if (!applyFootIK) return;
            if (!_animator) return;
            // Set the weights of left foot to the current value defined by the curve in the animations.
            _animator.SetIKPositionWeight(AvatarIKGoal.LeftFoot, _animator.GetFloat("IKLeftFootWeight"));
            _animator.SetIKRotationWeight(AvatarIKGoal.LeftFoot, _animator.GetFloat("IKLeftFootWeight"));

            //Left Foot
            RaycastHit hitInfo;
            //a ray starting from 1 unit above the IK Foot transform, and going downward on the Y Axis
            Ray ray = new Ray(_animator.GetIKPosition(AvatarIKGoal.LeftFoot) + Vector3.up, Vector3.down);
            Debug.DrawRay(_animator.GetIKPosition(AvatarIKGoal.LeftFoot) + Vector3.up, Vector3.down * (1f + distanceToGround), Color.red);

            if (Physics.Raycast(ray, out hitInfo, 1f + distanceToGround, targetLayer))
            {
                var footPosition = hitInfo.point; //The point in space where the ray hit the targetLayer ie: where the foot should be placed.
                footPosition.y += distanceToGround; //lifting the foot back up to compensate for the distanceToGround used above.
                _animator.SetIKPosition(AvatarIKGoal.LeftFoot, footPosition);
                //Rotating the foot in a direction so that Vector3.up's rotation matches the hit surface's normal rotation.
                _animator.SetIKRotation(AvatarIKGoal.LeftFoot, Quaternion.FromToRotation(Vector3.up, hitInfo.normal));
            }

            // Set the weights of left foot to the current value defined by the curve in the animations.
            _animator.SetIKPositionWeight(AvatarIKGoal.RightFoot, _animator.GetFloat("IKRightFootWeight"));
            _animator.SetIKRotationWeight(AvatarIKGoal.RightFoot, _animator.GetFloat("IKRightFootWeight"));

            //Right Foot
            //a ray starting from 1 unit above the IK Foot transform, and going downward on the Y Axis
            ray = new Ray(_animator.GetIKPosition(AvatarIKGoal.RightFoot) + Vector3.up, Vector3.down);
            Debug.DrawRay(_animator.GetIKPosition(AvatarIKGoal.LeftFoot) + Vector3.up, Vector3.down * (1f + distanceToGround), Color.red);

            if (Physics.Raycast(ray, out hitInfo, 1f + distanceToGround, targetLayer))
            {
                var footPosition = hitInfo.point; //The point in space where the ray hit the targetLayer ie: where the foot should be placed.
                footPosition.y += distanceToGround; //lifting the foot back up to compensate for the distanceToGround used above.

                _animator.SetIKPosition(AvatarIKGoal.RightFoot, footPosition);
                //Rotating the foot in a direction so that Vector3.up's rotation matches the hit surface's normal rotation.
                _animator.SetIKRotation(AvatarIKGoal.RightFoot, Quaternion.FromToRotation(Vector3.up, hitInfo.normal));
            }
        }
    }
}