问有关于回溯路径的问题

EN

    var pt1 = new Array ();     //key press time
    var pr1 = new Array ();     //key press release
    var pkh1 = new Array ();    //key press horizontal component
    var pkv1 = new Array();     // key press vertical component
    var level : int = 0;
    var i : int = 0;    // i is car number of this script
    var t1 : float = 0;
    var j1 : int = 0;
    var downUp;
    var heldUp;
    var upUp;
    var downDown;
    var heldDown;
    var upDown;
    var downLeft;
    var heldLeft;
    var upLeft;
    var downRight;
    var heldRight;
    var upRight;
    var downSpace;
    var heldSpace;
    var upSpace;

    var stopwatch : System.Diagnostics.Stopwatch  = new System.Diagnostics.Stopwatch();
    var stopwatch1 : System.Diagnostics.Stopwatch  = new System.Diagnostics.Stopwatch();

    var l = true;
        var speed : float = 6f;            // The speed that the player will move at.

        private var movement : Vector3;                   // The vector to store the direction of the player's movement.
        private var playerRigidbody : Rigidbody;          // Reference to the player's rigidbody.
        function Awake () {
          playerRigidbody = GetComponent (Rigidbody);
        }
        function move (h : float, v : float)
        {
    // Set the movement vector based on the axis input.
    movement.Set (h, 0f, v);

    // Normalise the movement vector and make it proportional to the speed per second.
    movement = movement.normalized * speed * Time.deltaTime;

    // Move the player to it's current position plus the movement.
    playerRigidbody.MovePosition (transform.position + movement);
    }



    function Start () {
    stopwatch.Start();
    }

function FixedUpdate ()
{
    // Store the input axes.
    var h : float = Input.GetAxisRaw ("Horizontal");
    var v : float = Input.GetAxisRaw ("Vertical");

    // Move the player around the scene.
    move (h, v);

}

function Update () 
{
    if(l) 
    {
    //for current player car
        downUp = Input.GetKeyDown(KeyCode.UpArrow);
        heldUp = Input.GetKey(KeyCode.UpArrow);
        upUp =  Input.GetKeyUp(KeyCode.UpArrow);
        if(downUp) 
        {
            pt1[j1] = stopwatch.ElapsedMilliseconds;
            pkh1[j1] = Input.GetAxisRaw ("Horizontal");
            pkv1[j1] = Input.GetAxisRaw ("Vertical");
        }
        if(heldUp) 
        {
        }
        if(upUp) 
        {
            pr1[j1] = stopwatch.ElapsedMilliseconds;
            j1++;
        }
        downDown = Input.GetKeyDown(KeyCode.DownArrow);
        heldDown = Input.GetKey(KeyCode.DownArrow);
        upDown =  Input.GetKeyUp(KeyCode.DownArrow);
        if(downDown) {
            pt1[j1] = stopwatch.ElapsedMilliseconds;
            pkh1[j1] = Input.GetAxisRaw ("Horizontal");
            pkv1[j1] = Input.GetAxisRaw ("Vertical");
        }
        if(heldDown) {
        }
        if(upDown) {
            pr1[j1]= stopwatch.ElapsedMilliseconds;
            j1++;
        }
        downLeft = Input.GetKeyDown(KeyCode.LeftArrow);
        heldLeft = Input.GetKey(KeyCode.LeftArrow);
        upLeft =  Input.GetKeyUp(KeyCode.LeftArrow);
        if(downLeft) {
            pt1[j1] = stopwatch.ElapsedMilliseconds;
            pkh1[j1] = Input.GetAxisRaw ("Horizontal");
            pkv1[j1] = Input.GetAxisRaw ("Vertical");
        }
        if(heldLeft) {
        }
        if(upLeft) {
            pr1[j1] = stopwatch.ElapsedMilliseconds;
            j1++;
        }
        downRight = Input.GetKeyDown(KeyCode.RightArrow);
        heldRight = Input.GetKey(KeyCode.RightArrow);
        upRight =  Input.GetKeyUp(KeyCode.RightArrow);
        if(downRight) {
            pt1[j1] = stopwatch.ElapsedMilliseconds;
            pkh1[j1] = Input.GetAxisRaw ("Horizontal");
            pkv1[j1] = Input.GetAxisRaw ("Vertical");
        }
        if(heldRight) {
        }
        if(upRight) {
            pr1[j1] = stopwatch.ElapsedMilliseconds;
            j1++;
        }
        downSpace = Input.GetKeyDown(KeyCode.A);
        heldSpace = Input.GetKey(KeyCode.A);
        upSpace =  Input.GetKeyUp(KeyCode.A);
        if(downSpace || heldSpace) 
        {
            transform.position = Vector3(0f,0f,0f);
            stopwatch.Stop();
            l = false;
            stopwatch1.Start();
            j1 = 0;
        }
    }
    else {
        t1 = stopwatch1.ElapsedMilliseconds;
        Debug.Log(j1);
        Debug.Log(transform.position);
        if(pt1[j1] <= t1) {
            while(pr1[j1] >= t1) {
                move(pkh1[j1], pkv1[j1]);   
            }
            j1++;
        }
    }   
}