input.getaxis 默认返回-1 unity 5.3.0

input.getaxis returning -1 by default unity 5.3.0

using UnityEngine;
using System.Collections;

public class Player : MonoBehaviour {

public float speed = 8.0f;
public float maxVelocity =3.0f;


// Use this for initialization
void Start () {

}

// Update is called once per frame
void Update () {

    float force = 0.0f;
    float velocity = Mathf.Abs (GetComponent<Rigidbody2D>().velocity.x);

    float h = Input.GetAxis ("Horizontal"); //getting input along x-axis only

    Debug.Log (h);

        if (h > 0) {
            if (velocity < maxVelocity) {
                force = speed;
            }
            Vector3 scale = transform.localScale;
            scale.x = 1;
            transform.localScale = scale;

        } else if (h < 0) {

            if (velocity < maxVelocity) {
                force = -speed;
            }

            Vector3 scale = transform.localScale;
            scale.x = -1;
            transform.localScale = scale;
        }

        GetComponent<Rigidbody2D>().AddForce (new Vector2 (force, 0));


    }
}

这里我的 h 值总是返回 -1 即使我没有按任何 right/left 键。

有人可以指出我的问题吗?

Input.GetAxis ("Horizontal") returns 范围 -1 中的值;1 用于您的操纵杆或其他控制器。请检查您是否没有连接到您的计算机。例如,它可以是赛车轮。