Custom signal
- Game Development course
- Intermediate
- Lesson 70/83
- 4 min
Learn to define custom signals with the signal keyword.
Defining custom signals
To create custom events for your game logic, you use the signal keyword. Signal declarations are typically placed at the very top of the script, before variables.
extends CharacterBody2D
signal health_changed(new_health)
signal player_diedCustom signals can be declared with or without parameters, just like built-in signals.
The power of parameterized signals
Adding parameters to custom signals conveys rich data to listeners. You can also use type hints to clarify the data types transported by the signal.
signal coin_collected(amount: int)
signal level_completed(level_name: String, score: int)This allows the listener function to receive the necessary values directly as arguments when triggered.
Practice Define custom signal and print
Define signal oyuna_baslandi at the top. Inside _ready, print "Ozel sinyal tanimlandi" to the console.
Starter code
extends Node
# Sinyali buraya tanimla
func _ready():
# Konsola yazdirSample solution
extends Node
signal oyuna_baslandi
func _ready():
print("Ozel sinyal tanimlandi")Expected output
Ozel sinyal tanimlandi
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 How do you declare a custom signal named 'can_degisti' carrying the new health value in GDScript?
- event can_degisti(yeni_can)
- signal can_degisti(yeni_can) Correct answer
- var can_degisti = Signal(yeni_can)
- def signal can_degisti(yeni_can)
Explanation: In GDScript, custom signals are declared using the 'signal' keyword followed by the name and argument list.
2 Write custom signal
# Skor degistiginde yayinlanacak sinyal
____ score_updated(new_score: int)# Skor degistiginde yayinlanacak sinyal
signal score_updated(new_score: int)Explanation: The 'signal' keyword is used to declare a custom signal.
3 Signal definition elements
| Term | Meaning |
|---|---|
signal |
Signal declaration keyword |
player_died |
Parameterless custom signal example |
score_changed(v) |
Parameterized custom signal |
new_health: int |
Typed signal parameter |