统一:使摄像机仅跟随玩家的 x 方向

我使用以下脚本，它使摄像机跟随播放器（在x和y方向上）：

using UnityEngine;
using System.Collections;
public class Camera2DFollow : MonoBehaviour {
    public Transform target;
    public float damping = 1;
    public float lookAheadFactor = 3;
    public float lookAheadReturnSpeed = 0.5f;
    public float lookAheadMoveThreshold = 0.1f;
    float offsetZ;
    Vector3 lastTargetPosition;
    Vector3 currentVelocity;
    Vector3 lookAheadPos;
    // Use this for initialization
    void Start () {
        lastTargetPosition = target.position;
        offsetZ = (transform.position - target.position).z;
        transform.parent = null;
    }
    // Update is called once per frame
    void Update () {
        // only update lookahead pos if accelerating or changed direction
        float xMoveDelta = (target.position - lastTargetPosition).x;
        bool updateLookAheadTarget = Mathf.Abs(xMoveDelta) > lookAheadMoveThreshold;
        if (updateLookAheadTarget) {
            lookAheadPos = lookAheadFactor * Vector3.right * Mathf.Sign(xMoveDelta);
        } else {
            lookAheadPos = Vector3.MoveTowards(lookAheadPos, Vector3.zero, Time.deltaTime * lookAheadReturnSpeed);  
        }
        Vector3 aheadTargetPos = target.position + lookAheadPos + Vector3.forward * offsetZ;
        Vector3 newPos = Vector3.SmoothDamp(transform.position, aheadTargetPos, ref currentVelocity, damping);
        transform.position = newPos;
        lastTargetPosition = target.position;       
    }
}

但是，我只希望它在x方向上跟随玩家。玩了一段时间的剧本，但想不通。