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SceneTree¶

Inherits: MainLoop < Object

Manages the game loop via a hierarchy of nodes.

描述¶

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.

教程¶

属性¶

bool	auto_accept_quit	`true`
Node	current_scene
bool	debug_collisions_hint	`false`
bool	debug_navigation_hint	`false`
bool	debug_paths_hint	`false`
Node	edited_scene_root
bool	multiplayer_poll	`true`
bool	paused	`false`
bool	quit_on_go_back	`true`
Window	root

Methods¶

void	call_group ( StringName group, StringName method, ... ) vararg
void	call_group_flags ( int flags, StringName group, StringName method, ... ) vararg
Error	change_scene_to_file ( String path )
Error	change_scene_to_packed ( PackedScene packed_scene )
SceneTreeTimer	create_timer ( float time_sec, bool process_always=true, bool process_in_physics=false, bool ignore_time_scale=false )
Tween	create_tween ( )
Node	get_first_node_in_group ( StringName group )
int	get_frame ( ) const
MultiplayerAPI	get_multiplayer ( NodePath for_path=NodePath("") ) const
int	get_node_count ( ) const
Node[]	get_nodes_in_group ( StringName group )
Tween[]	get_processed_tweens ( )
bool	has_group ( StringName name ) const
void	notify_group ( StringName group, int notification )
void	notify_group_flags ( int call_flags, StringName group, int notification )
void	queue_delete ( Object obj )
void	quit ( int exit_code=0 )
Error	reload_current_scene ( )
void	set_group ( StringName group, String property, Variant value )
void	set_group_flags ( int call_flags, StringName group, String property, Variant value )
void	set_multiplayer ( MultiplayerAPI multiplayer, NodePath root_path=NodePath("") )
void	unload_current_scene ( )

信号¶

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.

process_frame ( )

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

tree_changed ( )

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

tree_process_mode_changed ( )

This signal is only emitted in the editor, it allows the editor to update the visibility of disabled nodes. Emitted whenever any node's Node.process_mode is changed.

Enumerations¶

enum GroupCallFlags:

GroupCallFlags GROUP_CALL_DEFAULT = 0

Call a group with no flags (default).

GroupCallFlags GROUP_CALL_REVERSE = 1

Call a group in reverse scene order.

GroupCallFlags GROUP_CALL_DEFERRED = 2

Call a group at the end of the current frame (process or physics).

GroupCallFlags GROUP_CALL_UNIQUE = 4

Call a group only once even if the call is executed many times.

Note: 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.

Property Descriptions¶

bool auto_accept_quit = true

void set_auto_accept_quit ( bool value )
bool is_auto_accept_quit ( )

If true, the application automatically accepts quitting requests.

For mobile platforms, see quit_on_go_back.

Node current_scene

void set_current_scene ( Node value )
Node get_current_scene ( )

Returns the root node of the currently running scene, regardless of its structure.

Warning: Setting this directly might not work as expected, and will not add or remove any nodes from the tree, consider using change_scene_to_file or change_scene_to_packed instead.

bool debug_collisions_hint = false

void set_debug_collisions_hint ( bool value )
bool is_debugging_collisions_hint ( )

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

Note: This property is not designed to be changed at run-time. Changing the value of debug_collisions_hint while the project is running will not have the desired effect.

bool debug_navigation_hint = false

void set_debug_navigation_hint ( bool value )
bool is_debugging_navigation_hint ( )

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

Note: This property is not designed to be changed at run-time. Changing the value of debug_navigation_hint while the project is running will not have the desired effect.

bool debug_paths_hint = false

void set_debug_paths_hint ( bool value )
bool is_debugging_paths_hint ( )

If true, curves from Path2D and Path3D nodes will be visible when running the game from the editor for debugging purposes.

Note: This property is not designed to be changed at run-time. Changing the value of debug_paths_hint while the project is running will not have the desired effect.

Node edited_scene_root

void set_edited_scene_root ( Node value )
Node get_edited_scene_root ( )

The root of the edited scene.

bool multiplayer_poll = true

void set_multiplayer_poll_enabled ( bool value )
bool is_multiplayer_poll_enabled ( )

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

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

bool paused = false

void set_pause ( bool value )
bool is_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 quit_on_go_back = true

void set_quit_on_go_back ( bool value )
bool is_quit_on_go_back ( )

If true, the application quits automatically when navigating back (e.g. using the system "Back" button on Android).

To handle 'Go Back' button when this option is disabled, use DisplayServer.WINDOW_EVENT_GO_BACK_REQUEST.

Window root

Window get_root ( )

The SceneTree's root Window.

Method Descriptions¶

void call_group ( StringName group, StringName 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. If a node doesn't have the given method or the argument list does not match (either in count or in types), it will be skipped.

Note: call_group will call methods immediately on all members at once, which can cause stuttering if an expensive method is called on lots of members.

void call_group_flags ( int flags, StringName group, StringName 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. If a node doesn't have the given method or the argument list does not match (either in count or in types), it will be skipped.

# Call the method in a deferred manner and in reverse order.
get_tree().call_group_flags(SceneTree.GROUP_CALL_DEFERRED | SceneTree.GROUP_CALL_REVERSE)

Note: Group call flags are used to control the method calling behavior. By default, methods will be called immediately in a way similar to call_group. However, if the GROUP_CALL_DEFERRED flag is present in the flags argument, methods will be called at the end of the frame in a way similar to Object.set_deferred.

Error change_scene_to_file ( 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 new scene node is added to the tree at the end of the frame. This ensures that both scenes aren't running at the same time, while still freeing the previous scene in a safe way similar to Node.queue_free. As such, you won't be able to access the loaded scene immediately after the change_scene_to_file call.

Error change_scene_to_packed ( PackedScene packed_scene )

Changes the running scene to a new instance of the given PackedScene (which must be valid).

Returns @GlobalScope.OK on success, @GlobalScope.ERR_CANT_CREATE if the scene cannot be instantiated, or @GlobalScope.ERR_INVALID_PARAMETER if the scene is invalid.

Note: The new scene node is added to the tree at the end of the frame. You won't be able to access it immediately after the change_scene_to_packed call.

SceneTreeTimer create_timer ( float time_sec, bool process_always=true, bool process_in_physics=false, bool ignore_time_scale=false )

Returns a SceneTreeTimer which will emit SceneTreeTimer.timeout after the given time in seconds elapsed in this SceneTree.

If process_always is set to false, pausing the SceneTree will also pause the timer.

If process_in_physics is set to true, will update the SceneTreeTimer during the physics frame instead of the process frame (fixed framerate processing).

If ignore_time_scale is set to true, will ignore Engine.time_scale and update the SceneTreeTimer with the actual frame delta.

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

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

public async Task SomeFunction()
{
    GD.Print("start");
    await ToSignal(GetTree().CreateTimer(1.0f), SceneTreeTimer.SignalName.Timeout);
    GD.Print("end");
}

The timer will be automatically freed after its time elapses.

Note: The timer is processed after all of the nodes in the current frame, i.e. node's Node._process method would be called before the timer (or Node._physics_process if process_in_physics is set to true).

Tween create_tween ( )

Creates and returns a new Tween. The Tween will start automatically on the next process frame or physics frame (depending on TweenProcessMode).

Note: When creating a Tween using this method, the Tween will not be tied to the Node that called it. It will continue to animate even if the Node is freed, but it will automatically finish if there's nothing left to animate. If you want the Tween to be automatically killed when the Node is freed, use Node.create_tween or Tween.bind_node.

Node get_first_node_in_group ( StringName group )

Returns the first node in the specified group, or null if the group is empty or does not exist.

int get_frame ( ) const

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

MultiplayerAPI get_multiplayer ( NodePath for_path=NodePath("") ) const

Return the MultiplayerAPI configured for the given path, or the default one if for_path is empty.

Note: Only one MultiplayerAPI may be configured for any subpath. If one is configured for "/root/Foo" then calling this for "/root/Foo/Bar" will return the one configured for "/root/Foo", regardless if one is configured for that path.

int get_node_count ( ) const

Returns the number of nodes in this SceneTree.

Node[] get_nodes_in_group ( StringName group )

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

Tween[] get_processed_tweens ( )

Returns an array of currently existing Tweens in the SceneTree (both running and paused).

bool has_group ( StringName name ) const

Returns true if the given group exists.

A group exists if any Node in the tree belongs to it (see Node.add_to_group). Groups without nodes are removed automatically.

void notify_group ( StringName group, int notification )

Sends the given notification to all members of the group.

Note: notify_group will immediately notify all members at once, which can cause stuttering if an expensive method is called as a result of sending the notification to lots of members.

void notify_group_flags ( int call_flags, StringName group, int notification )

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

Note: Group call flags are used to control the notification sending behavior. By default, notifications will be sent immediately in a way similar to notify_group. However, if the GROUP_CALL_DEFERRED flag is present in the call_flags argument, notifications will be sent at the end of the current frame in a way similar to using Object.call_deferred("notification", ...).

void queue_delete ( Object obj )

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

void quit ( int exit_code=0 )

Quits the application at the end of the current iteration. Argument exit_code can optionally be given (defaulting to 0) to customize the exit status code.

By convention, an exit code of 0 indicates success whereas a non-zero exit code indicates an error.

For portability reasons, the exit code should be set between 0 and 125 (inclusive).

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_group ( StringName group, String property, Variant value )

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

Note: set_group will set the property immediately on all members at once, which can cause stuttering if a property with an expensive setter is set on lots of members.

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

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

Note: Group call flags are used to control the property setting behavior. By default, properties will be set immediately in a way similar to set_group. However, if the GROUP_CALL_DEFERRED flag is present in the call_flags argument, properties will be set at the end of the frame in a way similar to Object.call_deferred.

void set_multiplayer ( MultiplayerAPI multiplayer, NodePath root_path=NodePath("") )

Sets a custom MultiplayerAPI with the given root_path (controlling also the relative subpaths), or override the default one if root_path is empty.

Note: Only one MultiplayerAPI may be configured for any subpath. If one is configured for "/root/Foo" setting one for "/root/Foo/Bar" will be ignored. See get_multiplayer.

void unload_current_scene ( )

If a current scene is loaded, calling this method will unload it.