Supporting setting panel layout

editor/main.cpp

@@ -4,6 +4,7 @@
 #include "panels/asset_browser_panel.hpp"
 #include "panels/inspector_panel.hpp"
 #include "panels/scene_hierarchy_panel.hpp"
+#include "panels/viewport_panel.hpp"
 
 class Editor : public sophia::Application {
  public:
@@ -17,6 +18,13 @@ class Editor : public sophia::Application {
     panels().emplace<SceneHierarchyPanel>();
     panels().emplace<InspectorPanel>();
     panels().emplace<AssetBrowserPanel>();
+    panels().emplace<ViewportPanel>();
+
+    panels().setDefaultLayout(
+        {.left = {"Scene Hierarchy"},
+         .right = {"Inspector", "Frame Stats", "PanelRegistry"},
+         .bottom = {"Asset Browser", "Console"},
+         .center = {"Viewport"}});
   }
 
   void onUpdate(const sophia::FrameInfo& frameInfo) override {}