Megacity-Sample/Assets/Scripts/Utils/ResourcePreloaderUtility.cs

using System.Linq;
using UnityEditor;
#if UNITY_EDITOR
using UnityEditor.Callbacks;
#endif
using UnityEngine;
using UnityObject = UnityEngine.Object;

namespace Unity.MegaCity.Utils
{
    #if UNITY_EDITOR
    static class ResourcePreloaderUtility
    {
        [PostProcessScene]
        [MenuItem("GameObject/Create Resource Preloader")]
        static void CreateResourcePreloader()
        {
            if (UnityObject.FindObjectOfType<ResourcePreloader>() != null)
            {
                Debug.Log($"{typeof(ResourcePreloader)} already exists in this scene.");
                return;
            }

            var resources = AssetDatabase.FindAssets("t:Texture")
                .Select(guid => AssetDatabase.GUIDToAssetPath(guid))
                .Where(path => path.StartsWith("Assets/Textures/"))
                .Select(p => AssetDatabase.LoadAssetAtPath<Texture>(p))
                .Where(t => t.hideFlags == HideFlags.None)
                .ToList();

            new GameObject("Resource Preloader", typeof(ResourcePreloader))
                .GetComponent<ResourcePreloader>()
                .SetResources(resources);
        }
    }
    #endif
}