controller const correctness

src/app/core/controller.cc

@@ -99,14 +99,14 @@ void Controller::onInput() {
 
 void Controller::onLoad() { editor_.UpdateScreen(); }
 
-void Controller::doRender() {
+void Controller::doRender() const {
   SDL_RenderClear(sdl_renderer_.get());
   ImGui::Render();
   ImGui_ImplSDLRenderer_RenderDrawData(ImGui::GetDrawData());
   SDL_RenderPresent(sdl_renderer_.get());
 }
 
-void Controller::onExit() {
+void Controller::onExit() const {
   ImGui_ImplSDLRenderer_Shutdown();
   ImGui_ImplSDL2_Shutdown();
   ImGui::DestroyContext();
@@ -148,7 +148,7 @@ void Controller::CreateRenderer() {
   }
 }
 
-void Controller::CreateGuiContext() {
+void Controller::CreateGuiContext() const {
   // Create the ImGui and ImPlot contexts
   ImGui::CreateContext();
 

src/app/core/controller.h

@@ -26,13 +26,13 @@ class Controller {
   void onEntry();
   void onInput();
   void onLoad();
-  void doRender();
-  void onExit();
+  void doRender() const;
+  void onExit() const;
 
  private:
   void CreateWindow();
   void CreateRenderer();
-  void CreateGuiContext();
+  void CreateGuiContext() const;
   inline void quit() { active_ = false; }
   friend int ::main(int argc, char **argv);