Fix deadlock in scene loading

#1761 #1773

Source/Engine/Level/Level.cpp

@@ -416,7 +416,7 @@ public:
         }
 
         // Load scene
-        if (Level::loadScene(SceneAsset.Get()))
+        if (Level::loadScene(SceneAsset))
         {
             LOG(Error, "Failed to deserialize scene {0}", SceneId);
             CallSceneEvent(SceneEventType::OnSceneLoadError, nullptr, SceneId);
@@ -816,40 +816,10 @@ bool LevelImpl::unloadScenes()
     return false;
 }
 
-bool Level::loadScene(const Guid& sceneId)
-{
-    const auto sceneAsset = Content::LoadAsync<JsonAsset>(sceneId);
-    return loadScene(sceneAsset);
-}
-
-bool Level::loadScene(const String& scenePath)
-{
-    LOG(Info, "Loading scene from file. Path: \'{0}\'", scenePath);
-
-    // Check for missing file
-    if (!FileSystem::FileExists(scenePath))
-    {
-        LOG(Error, "Missing scene file.");
-        return true;
-    }
-
-    // Load file
-    BytesContainer sceneData;
-    if (File::ReadAllBytes(scenePath, sceneData))
-    {
-        LOG(Error, "Cannot load data from file.");
-        return true;
-    }
-
-    return loadScene(sceneData);
-}
-
 bool Level::loadScene(JsonAsset* sceneAsset)
 {
     // Keep reference to the asset (prevent unloading during action)
     AssetReference<JsonAsset> ref = sceneAsset;
-
-    // Wait for loaded
     if (sceneAsset == nullptr || sceneAsset->WaitForLoaded())
     {
         LOG(Error, "Cannot load scene asset.");
@@ -879,6 +849,7 @@ bool Level::loadScene(const BytesContainer& sceneData, Scene** outScene)
         return true;
     }
 
+    ScopeLock lock(ScenesLock);
     return loadScene(document, outScene);
 }
 
@@ -1332,6 +1303,7 @@ bool Level::LoadScene(const Guid& id)
     }
 
     // Load scene
+    ScopeLock lock(ScenesLock);
     if (loadScene(sceneAsset))
     {
         LOG(Error, "Failed to deserialize scene {0}", id);

Source/Engine/Level/Level.h

@@ -541,8 +541,8 @@ private:
     };
 
     static void callActorEvent(ActorEventType eventType, Actor* a, Actor* b);
-    static bool loadScene(const Guid& sceneId);
-    static bool loadScene(const String& scenePath);
+
+    // All loadScene assume that ScenesLock has been taken by the calling thread
     static bool loadScene(JsonAsset* sceneAsset);
     static bool loadScene(const BytesContainer& sceneData, Scene** outScene = nullptr);
     static bool loadScene(rapidjson_flax::Document& document, Scene** outScene = nullptr);

Source/Engine/Level/SceneObjectsFactory.cpp

@@ -280,9 +280,9 @@ void SceneObjectsFactory::HandleObjectDeserializationError(const ISerializable::
 #if USE_EDITOR
             // Add dummy script
             auto* dummyScript = parent->AddScript<MissingScript>();
-            const auto parentIdMember = value.FindMember("TypeName");
-            if (parentIdMember != value.MemberEnd() && parentIdMember->value.IsString())
-                dummyScript->MissingTypeName = parentIdMember->value.GetString();
+            const auto typeNameMember = value.FindMember("TypeName");
+            if (typeNameMember != value.MemberEnd() && typeNameMember->value.IsString())
+                dummyScript->MissingTypeName = typeNameMember->value.GetString();
             dummyScript->Data = MoveTemp(bufferStr);
 #endif
             LOG(Warning, "Parent actor of the missing object: {0}", parent->GetName());

Source/Engine/Platform/Win32/Win32CriticalSection.h

@@ -16,16 +16,13 @@ class FLAXENGINE_API Win32CriticalSection
     friend Win32ConditionVariable;
 
 private:
-
     mutable Windows::CRITICAL_SECTION _criticalSection;
 
 private:
-
     Win32CriticalSection(const Win32CriticalSection&);
     Win32CriticalSection& operator=(const Win32CriticalSection&);
 
 public:
-
     /// <summary>
     /// Initializes a new instance of the <see cref="Win32CriticalSection"/> class.
     /// </summary>
@@ -43,17 +40,12 @@ public:
     }
 
 public:
-
     /// <summary>
     /// Locks the critical section.
     /// </summary>
     void Lock() const
     {
-        // Spin first before entering critical section, causing ring-0 transition and context switch
-        if (Windows::TryEnterCriticalSection(&_criticalSection) == 0)
-        {
-            Windows::EnterCriticalSection(&_criticalSection);
-        }
+        Windows::EnterCriticalSection(&_criticalSection);
     }
 
     /// <summary>