Add support for virtual Prefab assets created from code

Source/Engine/Content/Asset.cpp

@@ -230,7 +230,8 @@ void Asset::OnDeleteObject()
         Content::GetRegistry()->DeleteAsset(id, nullptr);
 
         // Delete file
-        Content::deleteFileSafety(path, id);
+        if (!IsVirtual())
+            Content::deleteFileSafety(path, id);
     }
 #endif
 }
@@ -288,8 +289,13 @@ void Asset::OnScriptingDispose()
 
 void Asset::ChangeID(const Guid& newId)
 {
-    // Don't allow to change asset ids
+    // Only virtual asset can change ID
-    CRASH;
+    if (!IsVirtual())
+        CRASH;
+
+    const Guid oldId = _id;
+    ManagedScriptingObject::ChangeID(newId);
+    Content::onAssetChangeId(this, oldId, newId);
 }
 
 bool Asset::LastLoadFailed() const

Source/Engine/Content/Content.cpp

@@ -460,12 +460,16 @@ Asset* Content::LoadAsync(const StringView& path, const ScriptingTypeHandle& typ
 Array<Asset*> Content::GetAssets()
 {
     Array<Asset*> assets;
+    AssetsLocker.Lock();
     Assets.GetValues(assets);
+    AssetsLocker.Unlock();
     return assets;
 }
 
 const Dictionary<Guid, Asset*>& Content::GetAssetsRaw()
 {
+    AssetsLocker.Lock();
+    AssetsLocker.Unlock();
     return Assets;
 }
 
@@ -862,6 +866,13 @@ void Content::onAssetUnload(Asset* asset)
     LoadedAssetsToInvoke.Remove(asset);
 }
 
+void Content::onAssetChangeId(Asset* asset, const Guid& oldId, const Guid& newId)
+{
+    ScopeLock locker(AssetsLocker);
+    Assets.Remove(oldId);
+    Assets.Add(newId, asset);
+}
+
 bool Content::IsAssetTypeIdInvalid(const ScriptingTypeHandle& type, const ScriptingTypeHandle& assetType)
 {
     // Skip if no restrictions for the type

Source/Engine/Content/Content.h

@@ -358,6 +358,7 @@ private:
     static void tryCallOnLoaded(Asset* asset);
     static void onAssetLoaded(Asset* asset);
     static void onAssetUnload(Asset* asset);
+    static void onAssetChangeId(Asset* asset, const Guid& oldId, const Guid& newId);
     static Asset* load(const Guid& id, const ScriptingTypeHandle& type, AssetInfo& assetInfo);
 
 private:

Source/Engine/Content/JsonAsset.cpp

@@ -45,6 +45,29 @@ String JsonAssetBase::GetData() const
     return String((const char*)buffer.GetString(), (int32)buffer.GetSize());
 }
 
+bool JsonAssetBase::Init(const StringView& dataTypeName, const StringAnsiView& dataJson)
+{
+    CHECK_RETURN(IsVirtual(), true);
+    unload(true);
+    DataTypeName = dataTypeName;
+    DataEngineBuild = FLAXENGINE_VERSION_BUILD;
+
+    // Parse json document
+    {
+        PROFILE_CPU_NAMED("Json.Parse");
+        Document.Parse(dataJson.Get(), dataJson.Length());
+    }
+    if (Document.HasParseError())
+    {
+        Log::JsonParseException(Document.GetParseError(), Document.GetErrorOffset());
+        return true;
+    }
+    Data = &Document;
+
+    // Load asset-specific data
+    return loadAsset() != LoadResult::Ok;
+}
+
 const String& JsonAssetBase::GetPath() const
 {
 #if USE_EDITOR
@@ -114,6 +137,9 @@ void JsonAssetBase::GetReferences(Array<Guid>& output) const
 
 Asset::LoadResult JsonAssetBase::loadAsset()
 {
+    if (IsVirtual())
+        return LoadResult::Ok;
+
     // Load data (raw json file in editor, cooked asset in build game)
 #if USE_EDITOR
     BytesContainer data;

Source/Engine/Content/JsonAsset.h

@@ -50,6 +50,15 @@ public:
     /// </summary>
     API_PROPERTY() String GetData() const;
 
+    /// <summary>
+    /// Initializes the virtual Json asset with custom data.
+    /// </summary>
+    /// <remarks>Can be used only for virtual assets created at runtime.</remarks>
+    /// <param name="dataTypeName">The data type name from the header. Allows to recognize the data type.</param>
+    /// <param name="dataJson">The Json with serialized data.</param>
+    /// <returns>True if failed, otherwise false.</returns>
+    API_FUNCTION() bool Init(const StringView& dataTypeName, const StringAnsiView& dataJson);
+
 #if USE_EDITOR
     /// <summary>
     /// Parses Json string to find any object references inside it. It can produce list of references to assets and/or scene objects. Supported only in Editor.

Source/Engine/Level/Prefabs/Prefab.Apply.cpp

@@ -661,10 +661,16 @@ bool Prefab::ApplyAll(Actor* targetActor)
 
         // Assign references to the prefabs
         allPrefabs.EnsureCapacity(Math::RoundUpToPowerOf2(Math::Max(30, nestedPrefabIds.Count())));
+        const Dictionary<Guid, Asset*, HeapAllocation>& assetsRaw = Content::GetAssetsRaw();
+        for (auto& e : assetsRaw)
+        {
+            if (e.Value->GetTypeHandle() == Prefab::TypeInitializer)
+                nestedPrefabIds.AddUnique(e.Key);
+        }
         for (int32 i = 0; i < nestedPrefabIds.Count(); i++)
         {
             const auto nestedPrefab = Content::LoadAsync<Prefab>(nestedPrefabIds[i]);
-            if (nestedPrefab && nestedPrefab != this)
+            if (nestedPrefab && nestedPrefab != this && (nestedPrefab->Flags & ObjectFlags::WasMarkedToDelete) == 0)
             {
                 allPrefabs.Add(nestedPrefab);
             }
@@ -1079,6 +1085,10 @@ bool Prefab::UpdateInternal(const Array<SceneObject*>& defaultInstanceObjects, r
     LOG(Info, "Updating prefab data");
 
     // Reload prefab data
+    if (IsVirtual())
+    {
+        return Init(TypeName, StringAnsiView(tmpBuffer.GetString(), (int32)tmpBuffer.GetSize()));
+    }
 #if 1 // Set to 0 to use memory-only reload that does not modifies the source file - useful for testing and debugging prefabs apply
 #if COMPILE_WITH_ASSETS_IMPORTER
     Locker.Unlock();

Source/Engine/Level/Prefabs/Prefab.cpp

@@ -11,7 +11,7 @@
 #include "Engine/Scripting/Scripting.h"
 #endif
 
-REGISTER_JSON_ASSET(Prefab, "FlaxEngine.Prefab", false);
+REGISTER_JSON_ASSET(Prefab, "FlaxEngine.Prefab", true);
 
 Prefab::Prefab(const SpawnParams& params, const AssetInfo* info)
     : JsonAssetBase(params, info)