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[gdscript/en] Update for Godot 4 (#4607)
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@ -2,13 +2,14 @@
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language: GDScript
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contributors:
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- ["Wichamir", "https://github.com/Wichamir/"]
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- ["zacryol", "https://github.com/zacryol"]
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filename: learngdscript.gd
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---
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GDScript is a dynamically typed scripting language made specifically for
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free and open source game engine Godot. GDScript's syntax is similar to
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Python's. Its main advantages are ease of use and tight integration with
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the engine. It's a perfect fit for game development.
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GDScript is a dynamically and statically typed scripting language
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for the free and open source game engine Godot. Its syntax is vaguely
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similar to Python's. Its main advantages are ease of use and tight
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integration with the engine. It's a perfect fit for game development.
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## Basics
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@ -20,9 +21,16 @@ the engine. It's a perfect fit for game development.
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are
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written
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using
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docstrings.
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triple
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quoted
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strings
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"""
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# Doc Comments can add a decription to classes and fields
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# which can be viewed in the in-engine docs.
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## This class is a demonstration of GDScript
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# Script file is a class in itself and you can optionally define a name for it.
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class_name MyClass
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@ -41,8 +49,13 @@ var d = {
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"key" : "value",
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42 : true
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} # Dictionary holds key-value pairs.
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var p_arr = PoolStringArray(["Hi", "there", "!"]) # Pool arrays can
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# only hold a certain type.
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var p_arr = PackedStringArray(["Hi", "there", "!"]) # Packed Arrays can
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# only hold a certain type.
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# Doc comments can apply to properties
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## How many times this object has jumped
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var jump_count = 0
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# Built-in vector types:
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var v2 = Vector2(1, 2)
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@ -57,10 +70,15 @@ enum { ZERO, ONE , TWO, THREE }
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enum NamedEnum { ONE = 1, TWO, THREE }
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# Exported variables are visible in the inspector.
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export(int) var age
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export(float) var height
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export var person_name = "Bob" # Export type hints are unnecessary
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# if you set a default value.
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#
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# Either a type hint (explained later) or a default value are needed in order
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# for the editor to know what options to give
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@export var age: int
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@export var height: float
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@export var person_name = "Bob"
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# But both is also acceptable
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@export var favorite_color: String = "Green"
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@export var favorite_food := "Pizza"
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# Functions
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func foo():
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@ -69,6 +87,12 @@ func foo():
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func add(first, second):
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return first + second
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# Doc Comments on functions
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## Increases the Jump Count
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func jump():
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jump_count += 1
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# Printing values
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func printing():
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print("GDScript ", "is ", " awesome.")
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@ -76,6 +100,11 @@ func printing():
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printt("These", "words", "are", "divided", "by", "tabs.")
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printraw("This gets printed to system console.")
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# Lambdas
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var my_lambda = func(): print("hello from lambda!")
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my_lambda.call()
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# Math
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func doing_math():
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var first = 8
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@ -97,14 +126,14 @@ func control_flow():
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y = 2 # y was originally a float,
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# but we can change its type to int
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# using the power of dynamic typing!
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if x < y:
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print("x is smaller than y")
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elif x > y:
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print("x is bigger than y")
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else:
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print("x and y are equal")
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var a = true
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var b = false
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var c = false
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@ -119,7 +148,7 @@ func control_flow():
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for i in ["two", 3, 1.0]: # iterating over an array
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print(i)
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while x > y:
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printt(x, y)
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y += 1
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@ -147,7 +176,7 @@ func control_flow():
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continue
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_:
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print("Underscore is a default case.")
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# ternary operator (one line if-else statement)
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prints("x is", "positive" if x >= 0 else "negative")
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@ -191,7 +220,7 @@ func _physics_process(delta):
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# like here:
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func get_children():
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# Do some additional things here.
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var r = .get_children() # call parent's implementation
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var r = super() # call parent's implementation
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return r
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# Inner class
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@ -220,19 +249,19 @@ func _ready() -> void:
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# Create NodePath by passing String to its constructor:
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var path1 = NodePath("path/to/something")
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# Or by using NodePath literal:
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var path2 = @"path/to/something"
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var path2 = ^"path/to/something"
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# NodePath examples:
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var path3 = @"Sprite" # relative path, immediate child of the current node
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var path4 = @"Timers/Firerate" # relative path, child of the child
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var path5 = @".." # current node's parent
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var path6 = @"../Enemy" # current node's sibling
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var path7 = @"/root" # absolute path, equivalent to get_tree().get_root()
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var path8 = @"/root/Main/Player/Sprite" # absolute path to Player's Sprite
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var path9 = @"Timers/Firerate:wait_time" # accessing properties
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var path10 = @"Player:position:x" # accessing subproperties
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var path3 = ^"Sprite" # relative path, immediate child of the current node
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var path4 = ^"Timers/Firerate" # relative path, child of the child
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var path5 = ^".." # current node's parent
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var path6 = ^"../Enemy" # current node's sibling
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var path7 = ^"/root" # absolute path, equivalent to get_tree().get_root()
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var path8 = ^"/root/Main/Player/Sprite" # absolute path to Player's Sprite
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var path9 = ^"Timers/Firerate:wait_time" # accessing properties
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var path10 = ^"Player:position:x" # accessing subproperties
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# Finally, to get a reference use one of these:
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sprite = get_node(@"Sprite") as Sprite # always cast to the type you expect
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sprite = get_node(^"Sprite") as Sprite # always cast to the type you expect
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sprite = get_node("Sprite") as Sprite # here String gets
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# implicitly casted to NodePath
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sprite = get_node(path3) as Sprite
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@ -243,14 +272,17 @@ func _process(delta):
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# Now we can reuse the reference in other places.
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prints("Sprite has global_position of", sprite.global_position)
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# Use onready keyword to assign a value to
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# Use @onready annotation to assign a value to
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# a variable just before _ready executes.
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# This is a commonly used syntax sugar.
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onready var tween = $Tween as Tween
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@onready var other_sprite = $Sprite as Sprite
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# You can export NodePath, so you can assign it within the inspector.
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export var nodepath = @""
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onready var reference = get_node(nodepath) as Node
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@export var nodepath = ^""
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@onready var reference = get_node(nodepath) as Node
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# Or export Node directly
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@export var other_reference: Node
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```
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## Signals
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@ -263,27 +295,34 @@ class_name Player extends Node2D
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var hp = 10
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# Doc comments can go on signals too
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## Emitted when the player dies
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signal died() # define signal
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signal hurt(hp_old, hp_new) # signals can take arguments
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func apply_damage(dmg):
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var hp_old = hp
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hp -= dmg
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emit_signal("hurt", hp_old, hp) # emit signal and pass arguments
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hurt.emit(hp_old, hp) # emit signal and pass arguments
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if hp <= 0:
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emit_signal("died")
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died.emit()
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func _ready():
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# connect signal "died" to function "_on_death" defined in self
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self.connect("died", self, "_on_death")
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died.connect(_on_death)
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# Alternate way
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# needed if the target object is not self
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# died.connect(Callable(self, &"_on_death"))
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func _on_death():
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self.queue_free() # destroy Player on death
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queue_free() # destroy Player on death
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```
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## Type hints
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GDScript can optionally use static typing.
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GDScript can optionally use static typing, for both code clarity and
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performance benefits.
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```gdscript
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extends Node
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@ -292,15 +331,23 @@ var x: int # define typed variable
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var y: float = 4.2
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var z := 1.0 # infer type based on default value using := operator
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onready var node_ref_typed := $Child as Node
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var a: Array[int] = [1, 2, 3] # Array can also have its type content specified
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export var speed := 50.0
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enum NamedEnum { ONE = 1, TWO, THREE }
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var n: NamedEnum = NamedEnum.ONE # Enums can be used as types as well
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@onready var node_ref_typed := $Child as Node
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@export var speed := 50.0
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const CONSTANT := "Typed constant."
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signal example(arg: int)
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func _ready() -> void:
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# function returns nothing
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x = "string" # ERROR! Type can't be changed!
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a.append("q") # ERROR! Array[int] can't hold strings!
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return
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func join(arg1: String, arg2: String) -> String:
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@ -310,8 +357,6 @@ func join(arg1: String, arg2: String) -> String:
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func get_child_at(index: int) -> Node:
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# function takes an int and returns a Node
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return get_children()[index]
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signal example(arg: int) # ERROR! Signals can't take typed arguments!
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```
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## Further Reading
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