delayTracker.cs

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

public class delayTracker : MonoBehaviour
{
    public Transform tracker;
    public float delayTime = 0.5f;
    private List<trackerPos> trackerPoses;
    private int bufferSize = 100;
    private float fps;
    private int counter = 0;
    Referances referances;

    void Awake()
    {
        resetPosesBuffer(delayTime);
        referances = GameObject.FindGameObjectWithTag("GameManager").GetComponent<Referances>();
    }
    private void Start()
    {
    }

    void FixedUpdate()
    {
        if (tracker == null)
        {
            if (GetComponent<LittleOnes>().whichChild == 1 && !referances.manager.stop)
            {
                tracker = referances.player.transform;

            }
            else if (GetComponent<LittleOnes>().whichChild != 1 && !referances.manager.stop)
            {
                tracker = referances.littleOnes[GetComponent<LittleOnes>().whichChild - 2].transform;
            }

        }
        if (bufferSize > trackerPoses.Count) //grow the array until it reached the buffer size & do nothing until it is full
        {
            trackerPoses.Add(new trackerPos(tracker.position, tracker.rotation));
            return;
        }

        trackerPoses[counter % bufferSize] = new trackerPos(tracker.position, tracker.rotation);
        int followIndex = (counter % bufferSize) + 1; //point to the index furthest from just set

        if (followIndex == bufferSize) //handle out of bounds, set back to 0
            followIndex = 0;

        transform.position = trackerPoses[followIndex].position;
        transform.rotation = trackerPoses[followIndex].rotation;

        counter++;
    }

    public void resetPositionBufferSize(InputField trackerDelayInputField)
    {
        delayTime = float.Parse(trackerDelayInputField.text);
        resetPosesBuffer(delayTime);
    }

    void resetPosesBuffer(float _delayTime)
    {
        counter = 0;
        fps = 1.0f / Time.deltaTime;
        bufferSize = Mathf.CeilToInt(fps * _delayTime);
        trackerPoses = new List<trackerPos>();
        trackerPoses.Add(new trackerPos(tracker.position, tracker.rotation)); //fill first index
    }
}

class trackerPos
{
    public Vector3 position;
    public Quaternion rotation;

    public trackerPos(Vector3 _pos, Quaternion _rot)
    {
        position = _pos;
        rotation = _rot;
    }
}