void OnSceneLoaded(Scene scene, LoadSceneMode mode)
    {
        isLoading  = false;
        transition = FindObjectOfType <PostProcessDrawColor>();

        StartCoroutine(AnimTransition(1, 0));
    }
    // Start is called before the first frame update
    void Awake()
    {
        if (Instance != null)
        {
            Destroy(gameObject);
            return;
        }

        DontDestroyOnLoad(gameObject);
        Instance = this;
        SceneManager.sceneLoaded += OnSceneLoaded;

        transition = FindObjectOfType <PostProcessDrawColor>();
    }
    IEnumerator Draw()
    {
        PostProcessDrawColor postProcess = GetComponent <PostProcessDrawColor>();
        Material             originalMat = postProcess.material;

        postProcess.material = mat;
        float t = 0;

        while (t < 1)
        {
            t += Time.deltaTime / drawTime;
            postProcess.intensity = Mathf.Lerp(1, 0, t);

            yield return(null);
        }
        postProcess.material = originalMat;
    }