fix: Recompile spritesheet asset and thumbnail when source file is changed

sources/editor/Stride.Assets.Presentation/Thumbnails/SpriteSheetThumbnailCompiler.cs

@@ -1,9 +1,12 @@
 // Copyright (c) .NET Foundation and Contributors (https://dotnetfoundation.org/ & https://stride3d.net) and Silicon Studio Corp. (https://www.siliconstudio.co.jp)
 // Distributed under the MIT license. See the LICENSE.md file in the project root for more information.
 using System;
+using System.Collections.Generic;
+using System.IO;
 using Stride.Core.Assets;
 using Stride.Core.Assets.Compiler;
 using Stride.Core.BuildEngine;
+using Stride.Core.Serialization.Contents;
 using Stride.Core.Mathematics;
 using Stride.Assets.Sprite;
 using Stride.Editor.Thumbnails;
@@ -48,6 +51,22 @@ public SpriteSheetThumbnailCommand(ThumbnailCompilerContext context, AssetItem a
             {
             }
 
+            public override IEnumerable<ObjectUrl> GetInputFiles()
+            {
+                foreach (var input in base.GetInputFiles())
+                    yield return input;
+
+                var spriteSheet = (SpriteSheetAsset)Parameters.Asset;
+                if (spriteSheet?.Sprites == null)
+                    yield break;
+
+                foreach (var sprite in spriteSheet.Sprites)
+                {
+                    if (sprite.Source != null && File.Exists(sprite.Source))
+                        yield return new ObjectUrl(UrlType.File, sprite.Source);
+                }
+            }
+
             protected override void RenderSprites(RenderDrawContext context)
             {
                 if (LoadedAsset == null || LoadedAsset.Sprites == null || LoadedAsset.Sprites.Count == 0)

sources/engine/Stride.Assets/Sprite/SpriteSheetAssetCompiler.cs

@@ -131,6 +131,27 @@ protected override void ComputeAssemblyHash(BinarySerializationWriter writer)
                 writer.Write(TextureSerializationData.Version);
             }
 
+            public override IEnumerable<ObjectUrl> GetInputFiles()
+            {
+                if (Parameters.SheetAsset.Packing.Enabled)
+                {
+                    // When packing, source images are read directly from disk
+                    foreach (var sprite in Parameters.SheetAsset.Sprites)
+                    {
+                        if (sprite.Source != null && File.Exists(sprite.Source))
+                            yield return new ObjectUrl(UrlType.File, sprite.Source);
+                    }
+                }
+                else
+                {
+                    // When not packing, textures are compiled by TextureConvertCommands so re-run when they change
+                    foreach (var textureUrl in Parameters.ImageToTextureUrl.Values)
+                    {
+                        yield return new ObjectUrl(UrlType.Content, textureUrl);
+                    }
+                }
+            }
+
             protected override Task<ResultStatus> DoCommandOverride(ICommandContext commandContext)
             {
                 var assetManager = new ContentManager(MicrothreadLocalDatabases.ProviderService);