godot-signals-groups Checked

Build event-driven, decoupled Godot 4.7 gameplay with signals and node groups: declare and emit custom signals, connect with Callables (incl. bind/one-shot), and broadcast to many nodes via groups and call_group. Use when wiring node communication in a Godot project, replacing tight references with signals, emitting/connecting events, or porting 3.x connect("sig", self, "method") code.

Godot Signals & Groups (4.x)

Decouple nodes with the observer pattern (signals) and act on many nodes at once

(groups), instead of hard-coding references between scenes. Targets **Godot 4.7**.

Build event-driven, decoupled Godot 4.7 gameplay with signals and node groups: declare and emit custom signals, connect with Callables (incl. bind/one-shot), and broadcast to many nodes via groups and call_group. Use when wiring node communication in a Godot project, replacing tight references with signals, emitting/connecting events, or porting 3.x connect("sig", self, "method") code.

Godot Signals & Groups (4.x)

Decouple nodes with the observer pattern (signals) and act on many nodes at once

(groups), instead of hard-coding references between scenes. Targets **Godot 4.7**.

When to use

• Use when a node needs to tell others "something happened" (player died, item picked

up, wave cleared) without holding direct references to them.

• Use when you need to address a whole category of nodes at once ("pause all enemies",

"save every checkpoint").

**When *not* to use:** raw signal *syntax* basics → godot-gdscript; scene structure

and instancing → godot-nodes-scenes. For cross-scene global events, emit from an

autoload (see godot-nodes-scenes).

Core workflow

1. **Decide the direction.** A child/sub-scene should *emit* a signal upward; the parent

*connects* to it. This keeps the child reusable and ignorant of who listens.

2. **Declare typed signals** on the emitter; emit() them when the event occurs.

3. **Connect with a Callable** (sig.connect(_on_sig)), optionally in the editor's Node

dock. Use CONNECT_ONE_SHOT for fire-once, bind() to pass extra context.

4. **Use groups for broadcast**: add nodes to a named group, then iterate

get_tree().get_nodes_in_group(...) or call_group(...).

5. **Disconnect when needed** (e.g. before freeing a long-lived listener) and check

is_connected() to avoid duplicate connections.

Patterns

### 1. Emit upward, connect from the parent

# coin.gd (reusable pickup — knows nothing about the player or HUD)
extends Area2D
signal collected(value: int)

func _on_body_entered(body: Node) -> void:
    if body.is_in_group("player"):
        collected.emit(10)
        queue_free()

# level.gd (the parent wires the coin to game state)
func _ready() -> void:
    for coin in get_tree().get_nodes_in_group("coins"):
        coin.collected.connect(_on_coin_collected)

func _on_coin_collected(value: int) -> void:
    GameState.add_score(value)

### 2. Connect flags: one-shot and bind extra arguments

func _ready() -> void:
    # Fire exactly once, then auto-disconnect.
    $Door.opened.connect(_on_door_opened, CONNECT_ONE_SHOT)
    # bind() appends arguments supplied at connect time (after the signal's own args).
    $RedButton.pressed.connect(_on_button.bind("red"))

func _on_button(color: String) -> void:
    print("Pressed the %s button" % color)

### 3. Groups: broadcast to many nodes