SceneTree

Inherits: MainLoop < Object

Manages the game loop via a hierarchy of nodes.

Description

As one of the most important classes, the SceneTree manages the hierarchy of nodes in a scene as well as scenes themselves. Nodes can be added, retrieved and removed. The whole scene tree (and thus the current scene) can be paused. Scenes can be loaded, switched and reloaded.

You can also use the SceneTree to organize your nodes into groups: every node can be assigned as many groups as you want to create, e.g. an “enemy” group. You can then iterate these groups or even call methods and set properties on all the group’s members at once.

SceneTree is the default MainLoop implementation used by scenes, and is thus in charge of the game loop.

Tutorials

• 使用 SceneTree

• 多分辨率

Properties

Methods

Signals

• connected_to_server ( )

Emitted whenever this SceneTree‘s network_peer successfully connected to a server. Only emitted on clients.

• connection_failed ( )

Emitted whenever this SceneTree‘s network_peer fails to establish a connection to a server. Only emitted on clients.

• files_dropped ( PoolStringArray files, int screen )

Emitted 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.

• global_menu_action ( Variant id, Variant meta )

Emitted whenever global menu item is clicked.

• idle_frame ( )

Emitted immediately before Node._process is called on every node in the SceneTree.

• network_peer_connected ( int id )

Emitted whenever this SceneTree‘s network_peer connects with a new peer. ID is the peer ID of the new peer. Clients get notified when other clients connect to the same server. Upon connecting to a server, a client also receives this signal for the server (with ID being 1).

• network_peer_disconnected ( int id )

Emitted whenever this SceneTree‘s network_peer disconnects from a peer. Clients get notified when other clients disconnect from the same server.

• node_added ( Node node )

Emitted whenever a node is added to the SceneTree.

• node_configuration_warning_changed ( Node node )

Emitted when a node’s configuration changed. Only emitted in tool mode.

• node_removed ( Node node )

Emitted whenever a node is removed from the SceneTree.

• node_renamed ( Node node )

Emitted whenever a node is renamed.

• physics_frame ( )

Emitted immediately before Node._physics_process is called on every node in the SceneTree.

• screen_resized ( )

Emitted when the screen resolution (fullscreen) or window size (windowed) changes.

• server_disconnected ( )

Emitted whenever this SceneTree‘s network_peer disconnected from server. Only emitted on clients.

• tree_changed ( )

Emitted whenever the SceneTree hierarchy changed (children being moved or renamed, etc.).

Enumerations

enum GroupCallFlags:

• GROUP_CALL_DEFAULT = 0 —- Call a group with no flags (default).

• GROUP_CALL_REVERSE = 1 —- Call a group in reverse scene order.

• GROUP_CALL_REALTIME = 2 —- Call a group immediately (calls are normally made on idle).

• GROUP_CALL_UNIQUE = 4 —- Call a group only once even if the call is executed many times.

enum StretchMode:

• STRETCH_MODE_DISABLED = 0 —- No stretching.

• STRETCH_MODE_2D = 1 —- Render stretching in higher resolution (interpolated).

• STRETCH_MODE_VIEWPORT = 2 —- Keep the specified display resolution. No interpolation. Content may appear pixelated.

enum StretchAspect:

• STRETCH_ASPECT_IGNORE = 0 —- Fill the window with the content stretched to cover excessive space. Content may appear stretched.

• STRETCH_ASPECT_KEEP = 1 —- Retain the same aspect ratio by padding with black bars on either axis. This prevents distortion.

• STRETCH_ASPECT_KEEP_WIDTH = 2 —- Expand vertically. Left/right black bars may appear if the window is too wide.

• STRETCH_ASPECT_KEEP_HEIGHT = 3 —- Expand horizontally. Top/bottom black bars may appear if the window is too tall.

• STRETCH_ASPECT_EXPAND = 4 —- Expand in both directions, retaining the same aspect ratio. This prevents distortion while avoiding black bars.

Property Descriptions

• Node current_scene

The current scene.

• bool debug_collisions_hint

If true, collision shapes will be visible when running the game from the editor for debugging purposes.

• bool debug_navigation_hint

If true, navigation polygons will be visible when running the game from the editor for debugging purposes.

• Node edited_scene_root

The root of the edited scene.

• MultiplayerAPI multiplayer

The default MultiplayerAPI instance for this SceneTree.

• bool multiplayer_poll

If true (default value), enables automatic polling of the MultiplayerAPI for this SceneTree during idle_frame.

If false, you need to manually call MultiplayerAPI.poll to process network packets and deliver RPCs/RSETs. This allows running RPCs/RSETs in a different loop (e.g. physics, thread, specific time step) and for manual Mutex protection when accessing the MultiplayerAPI from threads.

• NetworkedMultiplayerPeer network_peer

The peer object to handle the RPC system (effectively enabling networking when set). Depending on the peer itself, the SceneTree will become a network server (check with is_network_server) and will set the root node’s network mode to master, or it will become a regular peer with the root node set to puppet. All child nodes are set to inherit the network mode by default. Handling of networking-related events (connection, disconnection, new clients) is done by connecting to SceneTree‘s signals.

• bool paused

If true, the SceneTree is paused. Doing so will have the following behavior:

• 2D and 3D physics will be stopped. This includes signals and collision detection.

• Node._process, Node._physics_process and Node._input will not be called anymore in nodes.

• bool refuse_new_network_connections

If true, the SceneTree‘s network_peer refuses new incoming connections.

• Viewport root

The SceneTree‘s root Viewport.

• bool use_font_oversampling

If true, font oversampling is used.

Method Descriptions

• Variant call_group ( String group, String method, … ) vararg

Calls method on each member of the given group. You can pass arguments to method by specifying them at the end of the method call. This method is equivalent of calling call_group_flags with GROUP_CALL_DEFAULT flag.

Note: method may only have 5 arguments at most (7 arguments passed to this method in total).

Note: Due to design limitations, call_group will fail silently if one of the arguments is null.

Note: call_group will always call methods with an one-frame delay, in a way similar to Object.call_deferred. To call methods immediately, use call_group_flags with the GROUP_CALL_REALTIME flag.

• Variant call_group_flags ( int flags, String group, String method, … ) vararg

Calls method on each member of the given group, respecting the given GroupCallFlags. You can pass arguments to method by specifying them at the end of the method call.

Note: method may only have 5 arguments at most (8 arguments passed to this method in total).

Note: Due to design limitations, call_group_flags will fail silently if one of the arguments is null.

# Call the method immediately and in reverse order.
get_tree().call_group_flags(SceneTree.GROUP_CALL_REALTIME | SceneTree.GROUP_CALL_REVERSE, "bases", "destroy")

• Error change_scene ( String path )

Changes the running scene to the one at the given path, after loading it into a PackedScene and creating a new instance.

Returns @GlobalScope.OK on success, @GlobalScope.ERR_CANT_OPEN if the path cannot be loaded into a PackedScene, or @GlobalScope.ERR_CANT_CREATE if that scene cannot be instantiated.

Note: The scene change is deferred, which means that the new scene node is added on the next idle frame. You won’t be able to access it immediately after the change_scene call.

• Error change_scene_to ( PackedScene packed_scene )

Changes the running scene to a new instance of the given PackedScene.

Returns @GlobalScope.OK on success or @GlobalScope.ERR_CANT_CREATE if the scene cannot be instantiated.

Note: The scene change is deferred, which means that the new scene node is added on the next idle frame. You won’t be able to access it immediately after the change_scene_to call.

• SceneTreeTimer create_timer ( float time_sec, bool pause_mode_process=true )

Returns a SceneTreeTimer which will SceneTreeTimer.timeout after the given time in seconds elapsed in this SceneTree. If pause_mode_process is set to false, pausing the SceneTree will also pause the timer.

Commonly used to create a one-shot delay timer as in the following example:

func some_function():
    print("start")
    yield(get_tree().create_timer(1.0), "timeout")
    print("end")

The timer will be automatically freed after its time elapses.

• int get_frame ( ) const

Returns the current frame number, i.e. the total frame count since the application started.

• PoolIntArray get_network_connected_peers ( ) const

Returns the peer IDs of all connected peers of this SceneTree‘s network_peer.

• int get_network_unique_id ( ) const

Returns the unique peer ID of this SceneTree‘s network_peer.

• int get_node_count ( ) const

Returns the number of nodes in this SceneTree.

• Array get_nodes_in_group ( String group )

Returns a list of all nodes assigned to the given group.

• int get_rpc_sender_id ( ) const

Returns the sender’s peer ID for the most recently received RPC call.

• bool has_group ( String name ) const

Returns true if the given group exists.

• bool has_network_peer ( ) const

Returns true if there is a network_peer set.

• bool is_input_handled ( )

Returns true if the most recent InputEvent was marked as handled with set_input_as_handled.

• bool is_network_server ( ) const

Returns true if this SceneTree‘s network_peer is in server mode (listening for connections).

• void notify_group ( String group, int notification )

Sends the given notification to all members of the group.

• void notify_group_flags ( int call_flags, String group, int notification )

Sends the given notification to all members of the group, respecting the given GroupCallFlags.

• void queue_delete ( Object obj )

Queues the given object for deletion, delaying the call to Object.free to after the current frame.

• void quit ( int exit_code=-1 )

Quits the application at the end of the current iteration. A process exit_code can optionally be passed as an argument. If this argument is 0 or greater, it will override the OS.exit_code defined before quitting the application.

Note: On iOS this method doesn’t work. Instead, as recommended by the iOS Human Interface Guidelines, the user is expected to close apps via the Home button.

• Error reload_current_scene ( )

Reloads the currently active scene.

Returns @GlobalScope.OK on success, @GlobalScope.ERR_UNCONFIGURED if no current_scene was defined yet, @GlobalScope.ERR_CANT_OPEN if current_scene cannot be loaded into a PackedScene, or @GlobalScope.ERR_CANT_CREATE if the scene cannot be instantiated.

• void set_auto_accept_quit ( bool enabled )

If true, the application automatically accepts quitting. Enabled by default.

For mobile platforms, see set_quit_on_go_back.

• void set_group ( String group, String property, Variant value )

Sets the given property to value on all members of the given group.

• void set_group_flags ( int call_flags, String group, String property, Variant value )

Sets the given property to value on all members of the given group, respecting the given GroupCallFlags.

• void set_input_as_handled ( )

Marks the most recent InputEvent as handled.

• void set_quit_on_go_back ( bool enabled )

If true, the application quits automatically on going back (e.g. on Android). Enabled by default.

To handle ‘Go Back’ button when this option is disabled, use MainLoop.NOTIFICATION_WM_GO_BACK_REQUEST.

• void set_screen_stretch ( StretchMode mode, StretchAspect aspect, Vector2 minsize, float scale=1 )

Configures screen stretching to the given StretchMode, StretchAspect, minimum size and scale.