• GDScript Tutorial：How to program in Godot - GDScript Tutorial - YouTube
• GDScript Tutorial with 中文字幕：Brackeys- How to program in Godobilibili
• Docs
  • 学习用 GDScript 编程 — Godot Engine (4.x) 简体中文文档
  • GDScript 参考 — Godot Engine (4.x) 简体中文文档
• Others:
  • Godot
  • Godot 4 Recipes

1 Syntax

1.0.1 Modifying nodes

$ is short for get_node()

@export var my_node: Sprite2D
@onready var weapon = $Player/Weapon

func _ready(): # called by engine
    $Label.text = "Hello, world!"

1.0.2 Input

输入示例 — Godot Engine (4.x) 简体中文文档

func _input()
    if event.is_action_pressed("my_action"):
        jump()

1.0.3 Variables

var health = 100 # dynamic typing
var health: int = 100 # static typing, this variable wiil always stay an integer
var health := 100 # inferred typing

@export var health := 100 # allow us to set it using the inspector

const GRAVITY = -9.81 # use CONSTANT_CASE

func _ready():
    heatlth += 10
    heatlth -= 10
    heatlth *= 10
    heatlth /= 10
    print("Health: "+ str(health))

注意 scope（作用域）

1.0.4 If statements

if x != y or y >= z:
    pass
elif y != z:
    pass
else:
    print("haha")

1.0.5 Data types

• bool
• int
• float
• string
• Vector2: stores two floats, x and y
• Vector3: stores three floats, x y z

var position = Vector3(1,2,3)
position.x += 2

1.0.6 Functions

func add(num1: int, num2: int) -> int:
    var result = num1 + num2
    return result

1.0.7 Random numbers

随机数生成

• randf() gives a random number between 0 and 1
• randf_range(from, to): gives a random floating-point number number between from and to
• rand_irange(int1, int2): gives a random integer number between int1 and int2

You can also set a fixed random seed instead using seed()

1.0.8 shuffle bag

我们希望随机挑选水果. 然而, 每次选择水果时依靠随机数生成会导致分布不那么 均匀 . 如果玩家足够幸运（或不幸）, 他们可能会连续三次或更多次得到相同的水果.

你可以使用 shuffle bag 模式来实现。它的工作原理是在选择数组后从数组中删除一个元素。多次选择之后，数组会被清空。当这种情况发生时，就将数组重新初始化为默认值。

var _fruits = ["apple", "orange", "pear", "banana"]

# A copy of the fruits array so we can restore the original value into `fruits`.

var _fruits_full = []


func _ready():
    randomize()
    _fruits_full = _fruits.duplicate() # deep copy
    _fruits.shuffle()

    for i in 100:
        print(get_fruit())


func get_fruit():
    if _fruits.is_empty():

        # Fill the fruits array again and shuffle it.

        _fruits = _fruits_full.duplicate()
        _fruits.shuffle()

    # Get a random fruit, since we shuffled the array,
    # and remove it from the `_fruits` array.

    var random_fruit = _fruits.pop_front()

    # Prints "apple", "orange", "pear", or "banana" every time the code runs.

    return random_fruit

1.0.9 Arrays

var array = []
var items: Array[String] = ["Knife", "Potion"]
items.append("Sword")
items[1] = "Damaged Knife"

1.0.10 Loops

# for loop

for item in items:
    print(item)

# while loop

while true: # DO NOT CREATE INFINIT LOOP!
    learn()

1.0.11 Dictionaries

key value pairs

var my_dict = {}
var employees = {
    "Jim": {"Salary":85, "Gender": "Male"},
    "Pam": {"Salary":80, "Gender": "Female"},,
}
players["Dwight"] = {"Salary":87, "Gender": "Male"}
print(employees["Jim"])

for employee in employees:
    print(employee + "'s salary:" + str(employees[employee]["Salary"] ))

1.0.12 Enums

枚举的成员是常量，所以大写

enum Suits { HEART,CLUB,DIAMOND,SPADE }
var card1 = Suit.CLUB
@export var card_suit: Suits

func _ready():
    if card1 == Suit.CLUB
        print("Club A")

最好将枚举的每个项写在单独的一行

enum Element {
    EARTH,
    WATER,
    AIR,
    FIRE,
}

1.0.13 Match statements

GDScript-match

func _ready():
    match Suits:
        Suits.HEART:
            print("Heart")
        Suits.CLUB:
            print("Club")
        _:
            print("Which suit is this card?")

1.0.14 Signals

最好用过去时态来命名信号。

func _on_button_pressed():
    pass

signal leveled_up(msg)

var xp := 0
for i in 8:
    xp += 5
    if xp >= 20:
        leveled_up.emit("DING!")

func _ready():
    leveled_up.connect(_on_leveled_up) # connect without inspector
    leveled_up.disconnect(_on_leveled_up)
    
func _on_leveled_up(msg):
    print(msg)

1.0.15 Setter and getter

GDScript-setter and getter set(value) 是变量的 setter 方法，用来控制变量被赋值时的行为。

var health := 100
    set(value):
        health = clamp(value, 0, 100)

其中 clamp(value, 0, 100) 将传入的 value 限制在 0 到 100 的范围内。

类似于 set 方法，get 方法用来控制变量在被读取时的行为，更常用于转换值：

var chance := 100
var chance_pct: int:
    get:
        return chance * 100
    set(value):
        chance = float(value)/100

1.0.16 Classes

https://www.bilibili.com/video/BV1mH4y1g7e5?t=3072.9 Godot 所有内置节点都是类

class_name Charactor

extends Node

1.0.17 Inner classes

var chest := Equipment.new()
var legs := Equipment.new()

func _ready():
    chest.armor = 20

# Inner class

class Equipment:
    var armor := 10
    var weight := 5

1.0.18 Composition

bitlytic How you can easily make your code simpler in Godot 4

1.1 Practices

1.1.1 Call down, signal up

Node communication 在层次结构中，节点可以调用位于其下方的节点上的函数，但反之则不然。

1.1.2 Memory management

GDScript-memory-management

1.1.3 Style

GDScript 编写风格指南

代码顺序：

01. @tool
02. class_name
03. extends
04. # docstring

05. signals
06. enums
07. constants
08. @export variables
09. public variables
10. private variables
11. @onready variables

12. optional built-in virtual _init method
13. optional built-in virtual _enter_tree() method
14. built-in virtual _ready method
15. remaining built-in virtual methods
16. public methods
17. private methods
18. subclasses