public class SphereMovement : MonoBehaviour
{
    [FormerlySerializedAs("movementSpeed")]
    [Header("Movement Setting")]
    [SerializeField, Range(0f, 10f)] private float maxSpeed = 5f;
    [SerializeField, Range(0f, 100f)] private float maxAcceleration = 10f;
    [SerializeField] Rect allowedArea = new Rect(-5f, -5f, 10f, 10f);

    public Vector3 Velocity;
    
    private PlayerInput _input;
    private Vector2 _moveInput;

    private void Start()
    {
        _input = GetComponent<PlayerInput>();
        Velocity = Vector3.zero;
    }

    private void Update()
    {
        _moveInput = _input.actions["Move"].ReadValue<Vector2>();
        // 根据输入得到预期速度
        Vector3 desiredVelocity = new Vector3(_moveInput.x, 0, _moveInput.y) * maxSpeed;
        // 当前时间片速度的最大变化量
        float maxSpeedChange = maxAcceleration * Time.deltaTime;
        // |target - current| <= maxDelta ? target : current + maxDelta
        Velocity.x = Mathf.MoveTowards(Velocity.x, desiredVelocity.x, maxSpeedChange);
        Velocity.z = Mathf.MoveTowards(Velocity.z, desiredVelocity.z, maxSpeedChange);
        // 新速度在当前时间片的位移
        Vector3 displacement = Velocity * Time.deltaTime;
        // 判断新位置是否越界
        Vector3 newPosition = transform.localPosition + displacement;
        if (newPosition.x < allowedArea.xMin) {
            newPosition.x = allowedArea.xMin;
            Velocity.x = 0f;
        }
        else if (newPosition.x > allowedArea.xMax) {
            newPosition.x = allowedArea.xMax;
            Velocity.x = 0f;
        }
        if (newPosition.z < allowedArea.yMin) {
            newPosition.z = allowedArea.yMin;
            Velocity.z = 0f;
        }
        else if (newPosition.z > allowedArea.yMax) {
            newPosition.z = allowedArea.yMax;
            Velocity.z = 0f;
        }
        // 修改位置
        transform.localPosition = newPosition;
    }
}