创建一个unity 第一人称脚本

以下是一个示例的Unity第一人称脚本：

using UnityEngine;

public class FirstPersonController : MonoBehaviour
{
    public float speed = 5.0f;
    public float sensitivity = 2.0f;

    private CharacterController controller;
    private Camera camera;
    private float verticalRotation = 0.0f;

    void Start()
    {
        controller = GetComponent<CharacterController>();
        camera = GetComponentInChildren<Camera>();
        Cursor.lockState = CursorLockMode.Locked;
    }

    void Update()
    {
        float horizontal = Input.GetAxis("Horizontal") * speed;
        float vertical = Input.GetAxis("Vertical") * speed;

        Vector3 movement = new Vector3(horizontal, 0, vertical);
        movement = transform.rotation * movement;
        controller.Move(movement * Time.deltaTime);

        float mouseHorizontal = Input.GetAxis("Mouse X") * sensitivity;
        float mouseVertical = Input.GetAxis("Mouse Y") * sensitivity;

        transform.Rotate(0, mouseHorizontal, 0);
        verticalRotation -= mouseVertical;
        verticalRotation = Mathf.Clamp(verticalRotation, -90f, 90f);
        camera.transform.localRotation = Quaternion.Euler(verticalRotation, 0, 0);

        if (Input.GetKeyDown(KeyCode.Escape))
        {
            Cursor.lockState = CursorLockMode.None;
        }
        else if (Cursor.lockState == CursorLockMode.None && Input.GetMouseButton(0))
        {
            Cursor.lockState = CursorLockMode.Locked;
        }
    }
}

该脚本包括以下功能：

- 按WSAD键移动角色
- 使用鼠标控制视角旋转
- 限制视角旋转角度
- 按Esc键解锁光标
- 按左键锁定光标