MainLoop

Inherits: Object Inherited By: SceneTree Abstract base class for the game’s main loop.

Description

MainLoop is the abstract base class for a Godot project’s game loop. It is inherited by SceneTree, which is the default game loop implementation used in Godot projects, though it is also possible to write and use one’s own MainLoop subclass instead of the scene tree. MainLoop implementation must be provided to the OS; otherwise, the application will exit. This happens automatically (and a SceneTree is created) unless a main Script is provided from the command line (with e.g. godot -s my_loop.gd, which should then be a MainLoop implementation. MainLoop:

  1. extends MainLoopvar time_elapsed = 0var keys_typed = []var quit = falsefunc _initialize():    print("Initialized:")    print("  Starting time: %s" % str(time_elapsed))func _idle(delta):    time_elapsed += delta    # Return true to end the main loop.    return quitfunc _input_event(event):    # Record keys.    if event is InputEventKey and event.pressed and !event.echo:        keys_typed.append(OS.get_scancode_string(event.scancode))        # Quit on Escape press.        if event.scancode == KEY_ESCAPE:            quit = true    # Quit on any mouse click.    if event is InputEventMouseButton:        quit = truefunc _finalize():    print("Finalized:")    print("  End time: %s" % str(time_elapsed))    print("  Keys typed: %s" % var2str(keys_typed))

Methods

Signals

  • on_request_permissions_result ( String permission, bool granted ) Emitted when a user responds to a permission request.

    Constants

  • NOTIFICATION_WM_MOUSE_ENTER = 1002 —- Notification received from the OS when the mouse enters the game window. Implemented on desktop and web platforms.
  • NOTIFICATION_WM_MOUSE_EXIT = 1003 —- Notification received from the OS when the mouse leaves the game window. Implemented on desktop and web platforms.
  • NOTIFICATION_WM_FOCUS_IN = 1004 —- Notification received from the OS when the game window is focused. Implemented on all platforms.
  • NOTIFICATION_WM_FOCUS_OUT = 1005 —- Notification received from the OS when the game window is unfocused. Implemented on all platforms.
  • NOTIFICATION_WM_QUIT_REQUEST = 1006 —- Notification received from the OS when a quit request is sent (e.g. closing the window with a “Close” button or Alt+F4). Implemented on desktop platforms.
  • NOTIFICATION_WM_GO_BACK_REQUEST = 1007 —- Notification received from the OS when a go back request is sent (e.g. pressing the “Back” button on Android). Specific to the Android platform.
  • NOTIFICATION_WM_UNFOCUS_REQUEST = 1008 —- Notification received from the OS when an unfocus request is sent (e.g. another OS window wants to take the focus). No supported platforms currently send this notification.
  • NOTIFICATION_OS_MEMORY_WARNING = 1009 —- Notification received from the OS when the application is exceeding its allocated memory. Specific to the iOS platform.
  • NOTIFICATION_TRANSLATION_CHANGED = 1010 —- Notification received when translations may have changed. Can be triggered by the user changing the locale. Can be used to respond to language changes, for example to change the UI strings on the fly. Useful when working with the built-in translation support, like Object.tr.
  • NOTIFICATION_WM_ABOUT = 1011 —- Notification received from the OS when a request for “About” information is sent. Specific to the macOS platform.
  • NOTIFICATION_CRASH = 1012 —- Notification received from Godot’s crash handler when the engine is about to crash. Implemented on desktop platforms if the crash handler is enabled.
  • NOTIFICATION_OS_IME_UPDATE = 1013 —- Notification received from the OS when an update of the Input Method Engine occurs (e.g. change of IME cursor position or composition string). Specific to the macOS platform.
  • NOTIFICATION_APP_RESUMED = 1014 —- Notification received from the OS when the app is resumed. Specific to the Android platform.
  • NOTIFICATION_APP_PAUSED = 1015 —- Notification received from the OS when the app is paused. Specific to the Android platform.

    Method Descriptions

  • _drop_files ( PoolStringArray files, int from_screen ) virtual Called when files are dragged from the OS file manager and dropped in the game window. The arguments are a list of file paths and the identifier of the screen where the drag originated.
  • _finalize ( ) virtual Called before the program exits.
  • _global_menu_action ( Variant id, Variant meta ) virtual Called when the user performs an action in the system global menu (e.g. the Mac OS menu bar).
  • bool _idle ( float delta ) virtual Node._process. true ends the main loop, while false lets it proceed to the next frame.
  • _initialize ( ) virtual Called once during initialization.
  • _input_event ( InputEvent event ) virtual InputEvent is received by the main loop.
  • _input_text ( String text ) virtual _input_event to parse text input. Will be removed in Godot 4.0.
  • bool _iteration ( float delta ) virtual delta, in seconds). Equivalent to Node._physics_process. true ends the main loop, while false lets it proceed to the next frame.
  • finish ( ) _finalize instead. Will be removed in Godot 4.0.
  • bool idle ( float delta ) _idle instead. Will be removed in Godot 4.0.
  • init ( ) _initialize instead. Will be removed in Godot 4.0.
  • input_event ( InputEvent event ) _input_event instead. Will be removed in Godot 4.0.
  • input_text ( String text ) _input_text instead. Will be removed in Godot 4.0.
  • bool iteration ( float delta ) _iteration instead. Will be removed in Godot 4.0.