Fix scenes reload feature to check if can do it, properly use async in play mode and ask for save if scene is modified

#1740

Source/Editor/Modules/SceneModule.cs

@@ -242,7 +242,6 @@ namespace FlaxEditor.Modules
         /// <param name="additive">True if don't close opened scenes and just add new scene to them, otherwise will release current scenes and load single one.</param>
         public void OpenScene(Guid sceneId, bool additive = false)
         {
-            // Check if cannot change scene now
             if (!Editor.StateMachine.CurrentState.CanChangeScene)
                 return;
 
@@ -271,11 +270,21 @@ namespace FlaxEditor.Modules
         /// </summary>
         public void ReloadScenes()
         {
+            if (!Editor.StateMachine.CurrentState.CanChangeScene)
+                return;
+
+            if (!Editor.IsPlayMode)
+            {
+                if (CheckSaveBeforeClose())
+                    return;
+            }
+
+            // Reload scenes
             foreach (var scene in Level.Scenes)
             {
                 var sceneId = scene.ID;
-                if (!Level.UnloadScene(scene))
-                    Level.LoadScene(sceneId);
+                Level.UnloadScene(scene);
+                Level.LoadScene(sceneId);
             }
         }
 
@@ -285,7 +294,6 @@ namespace FlaxEditor.Modules
         /// <param name="scene">The scene.</param>
         public void CloseScene(Scene scene)
         {
-            // Check if cannot change scene now
             if (!Editor.StateMachine.CurrentState.CanChangeScene)
                 return;
 
@@ -309,7 +317,6 @@ namespace FlaxEditor.Modules
         /// </summary>
         public void CloseAllScenes()
         {
-            // Check if cannot change scene now
             if (!Editor.StateMachine.CurrentState.CanChangeScene)
                 return;
 
@@ -334,7 +341,6 @@ namespace FlaxEditor.Modules
         /// <param name="scene">The scene to not close.</param>
         public void CloseAllScenesExcept(Scene scene)
         {
-            // Check if cannot change scene now
             if (!Editor.StateMachine.CurrentState.CanChangeScene)
                 return;
 

Source/Engine/Level/Level.cpp

@@ -1108,7 +1108,7 @@ bool LevelImpl::saveScene(Scene* scene)
 
 bool LevelImpl::saveScene(Scene* scene, const String& path)
 {
-    ASSERT(scene);
+    ASSERT(scene && EnumHasNoneFlags(scene->Flags, ObjectFlags::WasMarkedToDelete));
     auto sceneId = scene->GetID();
 
     LOG(Info, "Saving scene {0} to \'{1}\'", scene->GetName(), path);