Add flag for apps like an editor who doesn't render any scene in the main window.

engine/core/include/app.hpp

@@ -26,6 +26,8 @@ public:
     virtual void update([[maybe_unused]] const float delta_time) {}
 
     virtual void render([[maybe_unused]] GFXCommandBuffer* command_buffer) {}
+
+    virtual bool wants_no_scene_rendering() { return false; }
 };
 
 /// This is an app's equivalent main(). You can check command line arguments through Engine::comand_line_arguments.

engine/core/src/engine.cpp

@@ -769,7 +769,7 @@ void Engine::render(const int index) {
     }
 
     if(_renderer != nullptr)
-        _renderer->render(commandbuffer, _current_scene, *window->render_target, index);
+        _renderer->render(commandbuffer, _app->wants_no_scene_rendering() ? nullptr : _current_scene, *window->render_target, index);
 
     _gfx->submit(commandbuffer, index);
 }

tools/common/include/commoneditor.hpp

@@ -128,6 +128,8 @@ public:
     virtual void object_selected([[maybe_unused]] Object object) {}
     virtual void asset_selected([[maybe_unused]] std::filesystem::path path, [[maybe_unused]] AssetType type) {}
 
+    bool wants_no_scene_rendering() override { return true; }
+
     void createDockArea();
     void drawViewport(Scene* scene);
     void drawAssets();