Foot IK 1.3

using UnityEngine;

namespace AGD.Core.IK
{
    //TODO tune this system more to prevent foot from going inside a wall

    /// <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
    {
        [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 of the ray check from the IK Foot Transform towards the ground")]
        [Range(0,1)][SerializeField] private float checkDistance = 0;

        [Tooltip("the offset from the IK Foot Transform to the lowest point of the foot")]
        [Range(0,1)][SerializeField] private float feetOffset = 0;

        [Header("Stairs Climbing Parameters")]
        [Tooltip("The reference step height of the stairs")]
        [Range(0, 1)] [SerializeField] private float stepHeight = .4f;

        private Animator _animator;
        private Collider _collider;


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

        //Prevent collision with stairs non convex collider
        private void OnCollisionEnter(Collision other)
        {
            if (other.gameObject.tag == "Stairs")
            {
                Physics.IgnoreCollision(other.collider, _collider);
            }
        }

        private void OnAnimatorIK(int layerIndex)
        {
            if (!applyFootIK) return;
            if (!_animator) return;

            // Set the weights of feet IK 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"));
            _animator.SetIKPositionWeight(AvatarIKGoal.RightFoot, _animator.GetFloat("IKRightFootWeight"));
            _animator.SetIKRotationWeight(AvatarIKGoal.RightFoot, _animator.GetFloat("IKRightFootWeight"));

            //Variables used to calculated pelvis position after calculating the feet position
            var leftFootYOffset = 0f;
            var rightFootYOffset = 0f;

            //did the raycasts hitting a collider?
            bool rayHit_1 = false;
            bool rayHit_2 = false;

            //Setting IK Positions

            #region Left Foot

            //Raycasts starting from the center of the collider and going downward on the Y Axis passing through each foot.
            RaycastHit hitInfo_1;
            RaycastHit hitInfo_2;

            Ray ray_1 = new Ray(_animator.GetIKPosition(AvatarIKGoal.LeftFoot) + new Vector3(0,_collider.bounds.extents.y - feetOffset,0), Vector3.down);
            Ray ray_2 = new Ray(_animator.GetIKPosition(AvatarIKGoal.LeftFoot) + new Vector3(0,_collider.bounds.extents.y - feetOffset,.15f), Vector3.down);

            Debug.DrawRay(_animator.GetIKPosition(AvatarIKGoal.LeftFoot) + new Vector3(0,_collider.bounds.extents.y - feetOffset,0), Vector3.down * (_collider.bounds.extents.y + checkDistance), Color.red);
            Debug.DrawRay(_animator.GetIKPosition(AvatarIKGoal.LeftFoot) + new Vector3(0,_collider.bounds.extents.y - feetOffset,.15f), Vector3.down * (_collider.bounds.extents.y + checkDistance), Color.red);

            //Checking if rays are hitting something
            if (Physics.Raycast(ray_1, out hitInfo_1, _collider.bounds.extents.y + checkDistance,
                targetLayer))
            {
                rayHit_1 = true;
            }
            if (Physics.Raycast(ray_2, out hitInfo_2, _collider.bounds.extents.y + checkDistance,
                targetLayer))
            {
                rayHit_2 = true;
            }

            //If both
            if (rayHit_1 && rayHit_2)
            {

                var hitDistance_1 = (hitInfo_1.point - _animator.GetIKPosition(AvatarIKGoal.LeftFoot)).magnitude;
                var hitDistance_2 = (hitInfo_2.point - new Vector3(0,0,.15f) - _animator.GetIKPosition(AvatarIKGoal.LeftFoot)).magnitude;


                //Case climbing stairs & only toes should be on a step
                if (hitDistance_1 >= stepHeight && hitDistance_2 < stepHeight)
                {
                    //the length of the offset between the current foot position and it's target position
                    leftFootYOffset = hitDistance_2;

                    var footPosition = hitInfo_2.point - new Vector3(0,0,.15f); // same logic as above but with an offset that is the foot-toes distance.
                    footPosition.y += feetOffset; //lifting the foot back up to compensate for the feet Offset.
                    _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_2.normal));
                }
                else //the rest of the cases
                {
                    //the length of the offset between the current foot position and it's target position
                    leftFootYOffset = hitDistance_1;

                    var footPosition = hitInfo_1.point; //The point in space where the ray hit the targetLayer ie: where the foot should be placed.
                    footPosition.y += feetOffset; //lifting the foot back up to compensate for the feet Offset.
                    _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_1.normal));
                }
            }

            #endregion

            #region Right Foot

            //reset values
            rayHit_1 = false;
            rayHit_2 = false;

            //Raycasts starting from the center of the collider and going downward on the Y Axis passing through each foot.
            ray_1 = new Ray(_animator.GetIKPosition(AvatarIKGoal.RightFoot) + new Vector3(0,_collider.bounds.extents.y - feetOffset,0), Vector3.down);
            ray_2 = new Ray(_animator.GetIKPosition(AvatarIKGoal.RightFoot) + new Vector3(0,_collider.bounds.extents.y - feetOffset,.15f), Vector3.down);
            Debug.DrawRay(_animator.GetIKPosition(AvatarIKGoal.RightFoot) + new Vector3(0,_collider.bounds.extents.y - feetOffset,0),
                Vector3.down * (_collider.bounds.extents.y + checkDistance), Color.red);
            Debug.DrawRay(_animator.GetIKPosition(AvatarIKGoal.RightFoot) + new Vector3(0,_collider.bounds.extents.y - feetOffset,.15f),
                Vector3.down * (_collider.bounds.extents.y + checkDistance), Color.red);

            //Checking if rays are hitting something
            if (Physics.Raycast(ray_1, out hitInfo_1, _collider.bounds.extents.y + checkDistance, targetLayer))
            {
                rayHit_1 = true;
            }
            if (Physics.Raycast(ray_2, out hitInfo_2, _collider.bounds.extents.y + checkDistance, targetLayer))
            {
                rayHit_2 = true;
            }

            if (rayHit_1 && rayHit_2)
            {
                var hitDistance_1 = (hitInfo_1.point - _animator.GetIKPosition(AvatarIKGoal.RightFoot)).magnitude;
                var hitDistance_2 = (hitInfo_2.point - new Vector3(0,0,.15f) - _animator.GetIKPosition(AvatarIKGoal.RightFoot)).magnitude;
                //Debug.Log("hitDistance_1 : " + hitDistance_1 + "hitDistance_2 : " + hitDistance_2);

                //Case climbing stairs & only toes should be on a step
                if (hitDistance_1 >= stepHeight && hitDistance_2 < stepHeight)
                {
                    //the length of the offset between the current foot position and it's target position
                    rightFootYOffset = hitDistance_2;

                    var footPosition = hitInfo_2.point - new Vector3(0,0,.15f); // same logic as above but with an offset that is the foot-toes distance.
                    footPosition.y += feetOffset; //lifting the foot back up to compensate for the feet Offset.
                    _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_2.normal));
                }
                else //the rest of the cases
                {
                    //the length of the offset between the current foot position and it's target position
                    rightFootYOffset = hitDistance_1;

                    var footPosition = hitInfo_1.point; //The point in space where the ray hit the targetLayer ie: where the foot should be placed.
                    footPosition.y += feetOffset; //lifting the foot back up to compensate for the feet Offset.
                    _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_1.normal));
                }
            }
            #endregion

            #region Pelvis

            var pelvisYOffset = Mathf.Max(leftFootYOffset, rightFootYOffset);
            var pelvisOffset = new Vector3(0,pelvisYOffset,0);
            //var target = Vector3.Lerp(_animator.bodyPosition, _animator.bodyPosition - pelvisOffset, .15f);
            _animator.bodyPosition -= pelvisOffset * _animator.GetFloat("IKPelvisWeight");

            #endregion
        }
    }
}