CursorLock.cs

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

// author: mvaganov@hotmail.com
// license: Copyfree, public domain. This is free code! Great artists, steal this code!
// latest version at: https://pastebin.com/raw/zqd0yK40
namespace NS {
    public class CursorLock : MonoBehaviour {
        void FixedUpdate() {
            LockUpdate();
        }
        // whether cursor is visible or not
        private static bool m_cursorIsLocked = false;
        public static void LockUpdate() {
            if(Input.GetKeyUp(KeyCode.Escape)) {
                m_cursorIsLocked = false;
            } else if(Input.GetMouseButtonUp(0)) {
                m_cursorIsLocked = true;
            }

            if (m_cursorIsLocked) {
                Cursor.lockState = CursorLockMode.Locked;
                Cursor.visible = false;
            } else if (!m_cursorIsLocked) {
                Cursor.lockState = CursorLockMode.None;
                Cursor.visible = true;
            }
        }
    }
}