Refactored Asset Thumbnails, Fixed issue with some thumbnails not updating in places

Author: michaelsakharov

Prowl.Editor/AssetsDatabase/EditorAssetDatabase.cs

@@ -9,7 +9,6 @@
 using Prowl.Editor.Thumbnails;
 using Prowl.Editor.Importers;
 using Prowl.Runtime;
-using Prowl.Editor.GUI.Panels;
 using Prowl.Editor.Projects.Scripting;
 using Prowl.Editor.Projects;
 
@@ -30,6 +29,9 @@ public class EditorAssetDatabase : IAssetDatabase
     private readonly Dictionary<string, Guid> _pathToGuid = new(StringComparer.OrdinalIgnoreCase);
     private readonly ConcurrentDictionary<Guid, EngineObject> _loadedAssets = new();
     private readonly ConcurrentDictionary<Guid, (Guid parentGuid, int index)> _subAssetIndex = new();
+    // GPU-uploaded thumbnail cache. Main-thread-only (texture creation isn't thread-safe), same
+    // as _pathToGuid every UI that shows asset thumbnails shares this instead of keeping its own.
+    private readonly Dictionary<Guid, Runtime.Resources.Texture2D?> _thumbnailTextures = new();
     // Per-thread re-entrancy guard that breaks dependency/sub-asset cycles during deserialize.
     [ThreadStatic] private static HashSet<Guid>? _loadingStack;
     // Serializes the deserialize body so concurrent loads of the same asset collapse onto one.
@@ -628,6 +630,7 @@ private bool RunImport(AssetEntry entry)
                 _subAssetIndex.TryRemove(oldGuid, out _);
                 if (_loadedAssets.TryRemove(oldGuid, out var oldObj)) oldObj?.Dispose();
                 ThumbnailGenerator.DeleteThumbnail(oldGuid, _project.ThumbnailsPath);
+                InvalidateThumbnailTexture(oldGuid);
                 string oldCache = GetCachePath(oldGuid);
                 if (File.Exists(oldCache)) try { File.Delete(oldCache); } catch { }
             }
@@ -643,10 +646,12 @@ private bool RunImport(AssetEntry entry)
             // Update dependency graph
             _dependencies.SetDependencies(entry.Guid, ctx.Dependencies);
 
-            // Queue thumbnail generation (lazy, one per frame)
+            // Queue thumbnail generation (lazy, one per frame) and drop any cached GPU texture for
+            // the old content so the next access rebuilds it from the freshly generated thumbnail.
             {
                 string? sourceFile = ctx.MainAsset is Runtime.Resources.Texture2D ? absolutePath : null;
                 ThumbnailGenerator.Enqueue(entry.Guid, ctx.MainAsset, sourceFile);
+                InvalidateThumbnailTexture(entry.Guid);
             }
 
             return true;
@@ -810,6 +815,57 @@ internal static void ClearScenesAndPrefabForReload()
     /// <summary>Load a cached thumbnail for an asset. Returns (width, height, pixels) or null.</summary>
     public (int width, int height, byte[] pixels)? LoadThumbnail(Guid guid) => ThumbnailGenerator.LoadThumbnail(guid, _project.ThumbnailsPath);
 
+    /// <summary>
+    /// Resolve an asset GUID to its cached GPU thumbnail texture, building it from the on-disk
+    /// pixel cache (<see cref="LoadThumbnail"/>) on first use. Returns null when no thumbnail
+    /// exists yet. Shared by every UI that shows asset thumbnails (Project panel, asset pickers,
+    /// Terrain layer tiles, etc.) so there's one GPU copy per asset, invalidated automatically
+    /// whenever this database reimports or deletes that asset.
+    /// </summary>
+    public Runtime.Resources.Texture2D? GetThumbnailTexture(Guid guid)
+    {
+        if (guid == Guid.Empty) return null;
+
+        if (_thumbnailTextures.TryGetValue(guid, out var cached))
+            return cached;
+
+        var thumb = LoadThumbnail(guid);
+        if (thumb == null) return null;
+
+        try
+        {
+            var (w, h, pixels) = thumb.Value;
+            var tex = new Runtime.Resources.Texture2D((uint)w, (uint)h, false, TextureImageFormat.Color4b);
+            tex.SetData<byte>(pixels);
+            tex.SetTextureFilters(TextureMin.Linear, TextureMag.Linear);
+            _thumbnailTextures[guid] = tex;
+            return tex;
+        }
+        catch
+        {
+            _thumbnailTextures[guid] = null;
+            return null;
+        }
+    }
+
+    /// <summary>Dispose and drop a single cached thumbnail texture so it's rebuilt from disk on next access.</summary>
+    public void InvalidateThumbnailTexture(Guid guid)
+    {
+        if (_thumbnailTextures.TryGetValue(guid, out var tex))
+        {
+            tex?.Dispose();
+            _thumbnailTextures.Remove(guid);
+        }
+    }
+
+    /// <summary>Dispose and clear every cached thumbnail texture (e.g. after the thumbnail size setting changes).</summary>
+    public void ClearThumbnailTextureCache()
+    {
+        foreach (var tex in _thumbnailTextures.Values)
+            tex?.Dispose();
+        _thumbnailTextures.Clear();
+    }
+
     // ================================================================
     //  Asset CRUD
     // ================================================================
@@ -962,12 +1018,14 @@ public void DeleteAsset(string relativePath)
             var entry = _guidToEntry.TryGetValue(guid, out var e) ? e : null;
             DisposeAndRemove(guid);
             ThumbnailGenerator.DeleteThumbnail(guid, _project.ThumbnailsPath);
+            InvalidateThumbnailTexture(guid);
             if (entry?.SubAssets != null)
                 foreach (var sub in entry.SubAssets)
                 {
                     DisposeAndRemove(sub.Guid);
                     _subAssetIndex.TryRemove(sub.Guid, out _);
                     ThumbnailGenerator.DeleteThumbnail(sub.Guid, _project.ThumbnailsPath);
+                    InvalidateThumbnailTexture(sub.Guid);
 
                     // Clean sub-asset cache file
                     string subCachePath = GetCachePath(sub.Guid);
@@ -1192,14 +1250,14 @@ public void Reimport(Guid guid)
                 foreach (var sub in entry.SubAssets)
                     DisposeAndRemove(sub.Guid);
 
-            // Clear old thumbnails and invalidate UI cache
+            // Clear old thumbnails and invalidate the cached GPU texture
             ThumbnailGenerator.DeleteThumbnail(guid, _project.ThumbnailsPath);
-            ProjectPanel.InvalidateThumbnail(guid);
+            InvalidateThumbnailTexture(guid);
             if (entry.SubAssets != null)
                 foreach (var sub in entry.SubAssets)
                 {
                     ThumbnailGenerator.DeleteThumbnail(sub.Guid, _project.ThumbnailsPath);
-                    ProjectPanel.InvalidateThumbnail(sub.Guid);
+                    InvalidateThumbnailTexture(sub.Guid);
                 }
 
             entry.NeedsReimport = true;
@@ -1451,6 +1509,8 @@ public void Dispose()
         _watcher?.Dispose();
         _watcher = null;
 
+        ClearThumbnailTextureCache();
+
         // Clear the global registrations if they still point at this instance, so a torn-down
         // database (e.g. between tests) doesn't leave dangling statics behind.
         if (Instance == this) Instance = null;

Prowl.Editor/Core/EditorApplication.cs

@@ -1680,7 +1680,7 @@ public void SaveEditorWindowState()
     public void ClearEditorCache()
     {
         try { Thumbnails.ThumbnailGenerator.DeleteAll(); } catch { }
-        GUI.Panels.ProjectPanel.ClearThumbnailCache();
+        EditorAssetDatabase.Instance?.ClearThumbnailTextureCache();
         try
         {
             if (Project.Current != null && System.IO.File.Exists(Project.Current.EditorStatePath))

Prowl.Editor/GUI/CustomEditors/TerrainEditor.cs

@@ -246,7 +246,7 @@ private void DrawPaint(Paper paper, string id, Prowl.Scribe.FontFile font, Terra
                         paper.Box($"{id}_l{i}_bar").Width(2).Height(UnitValue.StretchOne)
                             .Margin(0, 0, UnitValue.Stretch(), UnitValue.Stretch())
                             .BackgroundColor(EditorTheme.Accent).IsNotInteractable();
-                    var albThumb = Prowl.Editor.GUI.Panels.ProjectPanel.GetThumbnailTexture(data.Layers[i].Albedo.AssetID);
+                    var albThumb = EditorAssetDatabase.Instance?.GetThumbnailTexture(data.Layers[i].Albedo.AssetID);
                     var swBox = paper.Box($"{id}_l{i}_sw").Width(16).Height(16).Rounded(4)
                         .Margin(0, 0, UnitValue.Stretch(), UnitValue.Stretch())
                         .BorderColor(EditorTheme.WithAlpha(SColor.White, 38)).BorderWidth(1).IsNotInteractable();
@@ -581,7 +581,7 @@ private void DrawProtoGrid(Paper paper, string id, Prowl.Scribe.FontFile font, i
                             .BorderColor(sel ? EditorTheme.WithAlpha(EditorTheme.Accent, 102) : SColor.Transparent).BorderWidth(1)
                             .OnClick(_ => onSelect(capture)).Enter())
                         {
-                            var thumb = Prowl.Editor.GUI.Panels.ProjectPanel.GetThumbnailTexture(getThumbGuid(idx));
+                            var thumb = EditorAssetDatabase.Instance?.GetThumbnailTexture(getThumbGuid(idx));
                             var thumbBox = paper.Box($"{id}_t{idx}_th").Width(46).Height(46).Rounded(9)
                                 .Margin(UnitValue.Stretch(), UnitValue.Stretch(), 0, 0)
                                 .BackgroundColor(EditorTheme.WithAlpha(tint, 34))

Prowl.Editor/GUI/Panels/PreferencesPanel.cs

@@ -130,7 +130,7 @@ private void DrawGeneral(Paper paper, EditorSettings s)
                     s.ThumbnailSize = v switch { 1 => 64, 2 => 128, _ => 32 };
                     s.Save();
                     ThumbnailGenerator.DeleteAll();
-                    ProjectPanel.ClearThumbnailCache();
+                    EditorAssetDatabase.Instance?.ClearThumbnailTextureCache();
                 }, thumbOptions).Show());
 
         EditorGUI.SectionHeader(paper, "pref_gen_maint", Loc.Get("pref.maintenance"));

Prowl.Editor/GUI/Panels/ProjectPanel.cs

@@ -73,7 +73,6 @@ public override void OnHeaderContent(Paper paper, float width, float height)
     private bool _contentBgHovered;
     // Rename state is managed by RenameOverlay
     private static readonly HashSet<Guid> _expandedAssets = new(); // files with sub-assets expanded
-    private static readonly Dictionary<Guid, Runtime.Resources.Texture2D?> _thumbnailCache = new();
     private static Guid _pendingPingNavigate; // Navigate to pinged asset's folder on next frame
     private static Guid _lastPingedGuid; // Track when a new ping starts
     private const float MinThumbSize = 20f;  // Below this = list mode
@@ -479,7 +478,7 @@ private void PerformAssetMove(AssetDragPayload payload, string destRelFolder)
 
         if (moved > 0)
         {
-            _thumbnailCache.Clear(); // paths changed thumbnail lookup may be stale
+            // Thumbnails are keyed by GUID, not path, so a move/rename doesn't invalidate them.
             Runtime.Debug.Log($"Moved {moved} item(s) to '{(string.IsNullOrEmpty(destRelFolder) ? "Assets" : destRelFolder)}'.");
         }
     }
@@ -1230,7 +1229,7 @@ private void DrawSubThumb(Paper paper, Scribe.FontFile font, ContentItem sub, in
             .Tooltip(sub.Name)
             .Enter())
         {
-            var thumbTex = GetThumbnailTexture(sub.Guid);
+            var thumbTex = EditorAssetDatabase.Instance?.GetThumbnailTexture(sub.Guid);
             if (thumbTex != null)
             {
                 paper.Box($"proj_subth_{sub.Guid}").Width(42).Height(42).Margin(ST, ST, 0, 0)
@@ -1350,7 +1349,7 @@ private void DrawGridItem(Paper paper, Scribe.FontFile font, string id, ContentI
             }
 
             // Thumbnail area
-            var thumbTex = GetThumbnailTexture(item.Guid);
+            var thumbTex = EditorAssetDatabase.Instance?.GetThumbnailTexture(item.Guid);
             if (thumbTex != null)
             {
                 // Rounded image tile (texture-brushed rounded rect) + a matching rounded border.
@@ -1566,56 +1565,6 @@ private static string FormatSize(long bytes)
 
     private static string GetFileIcon(string ext) => FileIconRegistry.GetIconForExtension(ext);
 
-    /// <summary>Resolve an asset GUID to its cached thumbnail texture (loads from disk on first use).
-    /// Returns null when no thumbnail exists yet. Shared with other editors (e.g. TerrainEditor tiles).</summary>
-    public static Runtime.Resources.Texture2D? GetThumbnailTexture(Guid guid)
-    {
-        if (guid == Guid.Empty) return null;
-
-        if (_thumbnailCache.TryGetValue(guid, out var cached))
-            return cached;
-
-        // Try loading from disk don't cache null so we retry when thumbnail is generated
-        var db = EditorAssetDatabase.Instance;
-        if (db == null) return null;
-
-        var thumb = db.LoadThumbnail(guid);
-        if (thumb == null) return null;
-
-        try
-        {
-            var (w, h, pixels) = thumb.Value;
-            var tex = new Runtime.Resources.Texture2D((uint)w, (uint)h, false, TextureImageFormat.Color4b);
-            tex.SetData<byte>(pixels);
-            tex.SetTextureFilters(TextureMin.Linear, TextureMag.Linear);
-            _thumbnailCache[guid] = tex;
-            return tex;
-        }
-        catch
-        {
-            _thumbnailCache[guid] = null;
-            return null;
-        }
-    }
-
-    /// <summary>Clear the thumbnail cache (e.g. after reimport).</summary>
-    public static void ClearThumbnailCache()
-    {
-        foreach (var tex in _thumbnailCache.Values)
-            tex?.Dispose();
-        _thumbnailCache.Clear();
-    }
-
-    /// <summary>Invalidate a single thumbnail so it reloads from disk on next access.</summary>
-    public static void InvalidateThumbnail(Guid guid)
-    {
-        if (_thumbnailCache.TryGetValue(guid, out var tex))
-        {
-            tex?.Dispose();
-            _thumbnailCache.Remove(guid);
-        }
-    }
-
     private static string GetSubAssetIcon(Type? type)
     {
         if (type == null) return EditorIcons.File;

Prowl.Editor/GUI/Popups/SelectorModal.cs

@@ -48,9 +48,6 @@ public static class SelectorModal
     private static Action<object?>? _callback;
     private static string _searchText = "";
 
-    // Thumbnail cache (shared with ProjectPanel would be ideal, but keep it simple)
-    private static readonly Dictionary<Guid, Texture2D?> _thumbCache = new();
-
     public static bool IsOpen => _open;
 
     /// <summary>
@@ -384,7 +381,7 @@ private static void DrawAssetsTab(Paper paper, Prowl.Scribe.FontFile font, float
     private static void DrawAssetGridItem(Paper paper, Prowl.Scribe.FontFile font,
         string id, Guid guid, string name, float cellSize, float labelH, float totalCellH)
     {
-        var thumbTex = GetThumbnailTexture(guid);
+        var thumbTex = EditorAssetDatabase.Instance?.GetThumbnailTexture(guid);
 
         using (paper.Column(id)
             .Width(cellSize).Height(totalCellH)
@@ -456,32 +453,4 @@ private static string GetHierarchyPath(GameObject go)
         parts.Reverse();
         return string.Join("/", parts);
     }
-
-    private static Texture2D? GetThumbnailTexture(Guid guid)
-    {
-        if (guid == Guid.Empty) return null;
-
-        if (_thumbCache.TryGetValue(guid, out var cached))
-            return cached;
-
-        var db = EditorAssetDatabase.Instance;
-        if (db == null) return null;
-
-        var thumb = db.LoadThumbnail(guid);
-        if (thumb == null) return null;
-
-        try
-        {
-            var (w, h, pixels) = thumb.Value;
-            var tex = new Texture2D((uint)w, (uint)h, false, TextureImageFormat.Color4b);
-            tex.SetData<byte>(pixels);
-            tex.SetTextureFilters(TextureMin.Linear, TextureMag.Linear);
-            _thumbCache[guid] = tex;
-            return tex;
-        }
-        catch
-        {
-            return null;
-        }
-    }
 }