struct SDL_Window; typedef union SDL_Event SDL_Event; bool ImGui_ImplSdl_Init(SDL_Window *window); void ImGui_ImplSdl_Shutdown(); void ImGui_ImplSdl_NewFrame(SDL_Window *window); bool ImGui_ImplSdl_EventCallback(const SDL_Event& event); void ImGui_ImplSdl_InvalidateDeviceObjects(); bool ImGui_ImplSdl_CreateDeviceObjects();