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.
Changes the running scene to the one at the given [code]path[/code], after loading it into a [PackedScene] and creating a new instance.
Returns [constant OK] on success, [constant ERR_CANT_OPEN] if the [code]path[/code] cannot be loaded into a [PackedScene], or [constant ERR_CANT_CREATE] if that scene cannot be instantiated.
[b]Note:[/b] 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 [method change_scene] call.
Changes the running scene to a new instance of the given [PackedScene].
Returns [constant OK] on success or [constant ERR_CANT_CREATE] if the scene cannot be instantiated.
[b]Note:[/b] 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 [method change_scene_to] call.
Returns a [SceneTreeTimer] which will [signal SceneTreeTimer.timeout] after the given time in seconds elapsed in this [SceneTree]. If [code]pause_mode_process[/code] is set to [code]false[/code], pausing the [SceneTree] will also pause the timer.
Commonly used to create a one-shot delay timer as in the following example:
[codeblock]
func some_function():
print("start")
yield(get_tree().create_timer(1.0), "timeout")
print("end")
[/codeblock]
The timer will be automatically freed after its time elapses.
</description>
</method>
<methodname="create_tween">
<returntype="SceneTreeTween"/>
<description>
Creates and returns a new [SceneTreeTween].
</description>
</method>
<methodname="get_first_node_in_group">
<returntype="Node"/>
<argumentindex="0"name="group"type="StringName"/>
<description>
Returns the first node in the specified group, or [code]null[/code] if the group is empty or does not exist.
</description>
</method>
<methodname="get_frame"qualifiers="const">
<returntype="int"/>
<description>
Returns the current frame number, i.e. the total frame count since the application started.
Quits the application at the end of the current iteration. A process [code]exit_code[/code] can optionally be passed as an argument. If this argument is [code]0[/code] or greater, it will override the [member OS.exit_code] defined before quitting the application.
[b]Note:[/b] 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.
</description>
</method>
<methodname="reload_current_scene">
<returntype="int"enum="Error"/>
<description>
Reloads the currently active scene.
Returns [constant OK] on success, [constant ERR_UNCONFIGURED] if no [member current_scene] was defined yet, [constant ERR_CANT_OPEN] if [member current_scene] cannot be loaded into a [PackedScene], or [constant ERR_CANT_CREATE] if the scene cannot be instantiated.
If [code]true[/code], collision shapes will be visible when running the game from the editor for debugging purposes.
[b]Note:[/b] This property is not designed to be changed at run-time. Changing the value of [member debug_collisions_hint] while the project is running will not have the desired effect.
If [code]true[/code], navigation polygons will be visible when running the game from the editor for debugging purposes.
[b]Note:[/b] This property is not designed to be changed at run-time. Changing the value of [member debug_navigation_hint] while the project is running will not have the desired effect.
If [code]true[/code] (default value), enables automatic polling of the [MultiplayerAPI] for this SceneTree during [signal idle_frame].
If [code]false[/code], you need to manually call [method 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.
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 [method 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.
If [code]true[/code], font oversampling is enabled. This means that [DynamicFont]s will be rendered at higher or lower size than configured based on the viewport's scaling ratio. For example, in a viewport scaled with a factor 1.5, a font configured with size 14 would be rendered with size 21 ([code]14 * 1.5[/code]).
[b]Note:[/b] Font oversampling is only used if the viewport stretch mode is [constant STRETCH_MODE_VIEWPORT], and if the stretch aspect mode is different from [constant STRETCH_ASPECT_IGNORE].
[b]Note:[/b] This property is set automatically for the active [SceneTree] when the project starts based on the configuration of [code]rendering/quality/dynamic_fonts/use_oversampling[/code] in [ProjectSettings]. The property can however be overridden at runtime as needed.
</member>
</members>
<signals>
<signalname="connected_to_server">
<description>
Emitted whenever this [SceneTree]'s [member network_peer] successfully connected to a server. Only emitted on clients.
</description>
</signal>
<signalname="connection_failed">
<description>
Emitted whenever this [SceneTree]'s [member network_peer] fails to establish a connection to a server. Only emitted on clients.
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.
</description>
</signal>
<signalname="global_menu_action">
<argumentindex="0"name="id"type="Variant"/>
<argumentindex="1"name="meta"type="Variant"/>
<description>
Emitted whenever global menu item is clicked.
</description>
</signal>
<signalname="idle_frame">
<description>
Emitted immediately before [method Node._process] is called on every node in the [SceneTree].
</description>
</signal>
<signalname="network_peer_connected">
<argumentindex="0"name="id"type="int"/>
<description>
Emitted whenever this [SceneTree]'s [member 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).
</description>
</signal>
<signalname="network_peer_disconnected">
<argumentindex="0"name="id"type="int"/>
<description>
Emitted whenever this [SceneTree]'s [member network_peer] disconnects from a peer. Clients get notified when other clients disconnect from the same server.
</description>
</signal>
<signalname="node_added">
<argumentindex="0"name="node"type="Node"/>
<description>
Emitted whenever a node is added to the [SceneTree].
</description>
</signal>
<signalname="node_configuration_warning_changed">
<argumentindex="0"name="node"type="Node"/>
<description>
Emitted when a node's configuration changed. Only emitted in [code]tool[/code] mode.
</description>
</signal>
<signalname="node_removed">
<argumentindex="0"name="node"type="Node"/>
<description>
Emitted whenever a node is removed from the [SceneTree].
</description>
</signal>
<signalname="node_renamed">
<argumentindex="0"name="node"type="Node"/>
<description>
Emitted whenever a node is renamed.
</description>
</signal>
<signalname="physics_frame">
<description>
Emitted immediately before [method Node._physics_process] is called on every node in the [SceneTree].
</description>
</signal>
<signalname="screen_resized">
<description>
Emitted when the screen resolution (fullscreen) or window size (windowed) changes.
</description>
</signal>
<signalname="server_disconnected">
<description>
Emitted whenever this [SceneTree]'s [member network_peer] disconnected from server. Only emitted on clients.
</description>
</signal>
<signalname="tree_changed">
<description>
Emitted whenever the [SceneTree] hierarchy changed (children being moved or renamed, etc.).
Call a group only once even if the call is executed many times.
[b]Note:[/b] Arguments are not taken into account when deciding whether the call is unique or not. Therefore when the same method is called with different arguments, only the first call will be performed.
