⭐️My favorite and lazy class implementing game loading animation on Unity⭐️

Curtain.cs

// ReSharper disable All
// **************************************************************** //
//
//   Copyright (c) RimuruDev. All rights reserved.
//   Contact me: 
//          - Gmail:    rimuru.dev@gmail.com
//          - GitHub: https://github.com/RimuruDev
//          - LinkedIn: https://www.linkedin.com/in/rimuru/
//
// **************************************************************** //

using UnityEngine;

namespace RimuruDev.Internal.Codebase.Runtime.Curtain
{
    [CreateAssetMenu(menuName = "StaticData/Create CurtainConfig", fileName = "CurtainConfig", order = 0)]
    public sealed class CurtainConfig : ScriptableObject
    {
        [field: SerializeField] public CurtainView CurtainView { get; private set; }

        [field: Space(20)]
        [field: SerializeField]
        public float HideDelay { get; private set; } = 1.3f;

        [field: SerializeField] public float AnimationDuration { get; private set; } = 1.5f;
    }
}

CurtainView.cs

// ReSharper disable All
// **************************************************************** //
//
//   Copyright (c) RimuruDev. All rights reserved.
//   Contact me: 
//          - Gmail:    rimuru.dev@gmail.com
//          - GitHub: https://github.com/RimuruDev
//          - LinkedIn: https://www.linkedin.com/in/rimuru/
//
// **************************************************************** //

using System;
using DG.Tweening;
using UnityEngine;

namespace RimuruDev.Internal.Codebase.Runtime.Curtain
{
    [SelectionBase]
    [DisallowMultipleComponent]
    public sealed class CurtainView : MonoBehaviour
    {
        [SerializeField] private CanvasGroup canvasGroup;
        private float animationDuration;

        public void Constructor(float animationDuration)
        {
            this.animationDuration = animationDuration;

            DontDestroyOnLoad(this);
        }

        public void ShowCurtain(bool isAnimated, Action callback)
        {
            canvasGroup.DOKill();
            gameObject.SetActive(true);

            if (!isAnimated)
            {
                canvasGroup.alpha = 1;
                callback?.Invoke();
                return;
            }

            canvasGroup.alpha = 0;
            canvasGroup
                .DOFade(1, animationDuration)
                .OnComplete(() => callback?.Invoke());
        }

        public void HideCurtain(bool isAnimated, Action callback)
        {
            canvasGroup.DOKill();

            if (!isAnimated)
            {
                gameObject.SetActive(false);
                callback?.Invoke();

                return;
            }

            canvasGroup
                .DOFade(0, animationDuration)
                .OnComplete(() =>
                {
                    gameObject.SetActive(false);
                    callback?.Invoke();
                });
        }

        public void HideCurtain(float startDelay, Action callback)
        {
            canvasGroup
                .DOFade(0, animationDuration)
                .SetDelay(startDelay)
                .OnComplete(() =>
                {
                    gameObject.SetActive(false);
                    callback?.Invoke();
                });
        }
    }
}

Example.cs

// ReSharper disable All
// **************************************************************** //
//
//   Copyright (c) RimuruDev. All rights reserved.
//   Contact me: 
//          - Gmail:    rimuru.dev@gmail.com
//          - GitHub: https://github.com/RimuruDev
//          - LinkedIn: https://www.linkedin.com/in/rimuru/
//
// **************************************************************** //

namespace RimuruDev.Internal.Codebase.Infrastructure.StateMachine.States
{
    public sealed class LoadMaiMenuState : IStateNext
    {
        private readonly ICurtainService curtain;
        private readonly ISceneLoaderService sceneLoader;
        private readonly IStaticDataService staticData;
        private readonly IUIFactory uiFactory;
        private IGameStateMachine gameStateMachine;

        [Inject]
        public LoadMaiMenuState(
            IStaticDataService staticData,
            ICurtainService curtain,
            IUIFactory uiFactory,
            ISceneLoaderService sceneLoader)
        {
            this.sceneLoader = sceneLoader;
            this.staticData = staticData;
            this.curtain = curtain;
            this.uiFactory = uiFactory;
        }

        public void Init(IGameStateMachine gameStateMachine) => 
            this.gameStateMachine = gameStateMachine;

        public void Enter()
        {
            // *** Hide Curtain *** //
            var config = staticData.ForCurtain();
            curtain.HideCurtain(config.HideDelay);

            sceneLoader.LoadScene(SceneName.Gameplay, OnSceneLoaded);
        }

        public void Exit() {}
        
        private void OnSceneLoaded() => 
            curtain.ShowCurtain(true, () => { gameStateMachine.EnterState<LoadGameplayState>(); });
    }
}