Porting Godot 4: OS

Overview

The OS singleton is essentially Godot's translator into a lot of your platform's low level features. It's used for various things like setting up/running a main loop, to getting the tick offset, to displaying errors, etc.

Compared to some other features to implement, implementing an OS singleton class is very rigid, with a lot of specific functions expected by the engine. Luckily, a decent chunk of those functions are only relevant within the engine's code, as in they do not need to be redefined in an OS derived class for a platform.

What MUST Be Implemented

Public functions:

• print(): Used by Godot to print information to terminal
• printerr(): Used by Godot to print errors to terminal
• alert(): An OS/system native way to create a warning popup
• add_logger()
• set_cmdline()
• ensure_user_data_dir()
• initialize()
• finalize()
• finalize_core()
• delay_usec()
• get_ticks_usec()
• benchmark_begin_measure()
• benchmark_end_measure()
• benchmark_dump()
• set_use_benchmark(bool benchmark)
• set_benchmark_file(String file)
• set_current_rendering_driver_name(String name)
• set_current_rendering_method(String method)
• get_cmdline_platform_args()
• set_cwd(String p)
• set_environment()
• unset_environment()
• run(): Starts your platform's main loop.
• get_main_loop()
• set_main_loop()
• delete_main_loop()
• add_frame_delay()
• set_exit_code()
• setup_remote_filesystem()
• set_display_driver_id()
• set_low_processor_usage_mode()
• set_low_processor_usage_mode_sleep_usec()
• set_delta_smoothing()
• get_executable_path()
• set_exit_code()
• get_render_thread_mode()
• initialize_joypads()
• get_bundle_icon_path()
• is_in_low_processor_mode()
• is_start_on_exit_set()
• get_restart_on_exit_arguments()
• create_instance(List<String> args)
• set_restart_on_exit()

Public variables:

• OS::RenderThreadMode _render_thread_mode
• bool _verbose_stdout
• List<String> _cmdline
• List <String> _user_args
• String _execpath
• String _local_clipboard