[Unity]카메라 360 회전 시, 부드럽게(관성)회전 방법

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ObjectRotation : MonoBehaviour
{
    public float rotationSpeed = 15;//회전속도
    public float smoothness = 5;//관성 값
    private Quaternion targetRotation = Quaternion.identity;

    void Update()
    {
        //회전
        if (Input.GetMouseButton(0))
        {
            Quaternion rot = transform.rotation;
            rot *= Quaternion.Euler(new Vector3(Input.GetAxis("Mouse Y") * rotationSpeed, -Input.GetAxis("Mouse X") * rotationSpeed, 0));

            float x = rot.eulerAngles.x;
            float y = rot.eulerAngles.y;
            targetRotation = Quaternion.Euler(x, y, 0);
        }
        transform.rotation = Quaternion.Lerp(transform.rotation, targetRotation, Time.deltaTime * smoothness);

    }
}