925236118/alphaagent/godot-gdscript-patterns

Node: Base building block
├── Scene: Reusable node tree (saved as .tscn)
├── Resource: Data container (saved as .tres)
├── Signal: Event communication
└── Group: Node categorization

class_name Player
extends CharacterBody2D
 
# Signals
signal health_changed(new_health: int)
signal died
 
# Exports (Inspector-editable)
@export var speed: float = 200.0
@export var max_health: int = 100
@export_range(0, 1) var damage_reduction: float = 0.0
@export_group("Combat")
@export var attack_damage: int = 10
@export var attack_cooldown: float = 0.5
 
# Onready (initialized when ready)
@onready var sprite: Sprite2D = $Sprite2D
@onready var animation: AnimationPlayer = $AnimationPlayer
@onready var hitbox: Area2D = $Hitbox
 
# Private variables (convention: underscore prefix)
var _health: int
var _can_attack: bool = true
 
func _ready() -> void:
    _health = max_health
 
func _physics_process(delta: float) -> void:
    var direction := Input.get_vector("left", "right", "up", "down")
    velocity = direction * speed
    move_and_slide()
 
func take_damage(amount: int) -> void:
    var actual_damage := int(amount * (1.0 - damage_reduction))
    _health = max(_health - actual_damage, 0)
    health_changed.emit(_health)
 
    if _health <= 0:
        died.emit()

# state_machine.gd
class_name StateMachine
extends Node
 
signal state_changed(from_state: StringName, to_state: StringName)
 
@export var initial_state: State
 
var current_state: State
var states: Dictionary = {}
 
func _ready() -> void:
    # Register all State children
    for child in get_children():
        if child is State:
            states[child.name] = child
            child.state_machine = self
            child.process_mode = Node.PROCESS_MODE_DISABLED
 
    # Start initial state
    if initial_state:
        current_state = initial_state
        current_state.process_mode = Node.PROCESS_MODE_INHERIT
        current_state.enter()
 
func _process(delta: float) -> void:
    if current_state:
        current_state.update(delta)
 
func _physics_process(delta: float) -> void:
    if current_state:
        current_state.physics_update(delta)
 
func _unhandled_input(event: InputEvent) -> void:
    if current_state:
        current_state.handle_input(event)
 
func transition_to(state_name: StringName, msg: Dictionary = {}) -> void:
    if not states.has(state_name):
        push_error("State '%s' not found" % state_name)
        return
 
    var previous_state := current_state
    previous_state.exit()
    previous_state.process_mode = Node.PROCESS_MODE_DISABLED
 
    current_state = states[state_name]
    current_state.process_mode = Node.PROCESS_MODE_INHERIT
    current_state.enter(msg)
 
    state_changed.emit(previous_state.name, current_state.name)

# state.gd
class_name State
extends Node
 
var state_machine: StateMachine
 
func enter(_msg: Dictionary = {}) -> void:
    pass
 
func exit() -> void:
    pass
 
func update(_delta: float) -> void:
    pass
 
func physics_update(_delta: float) -> void:
    pass
 
func handle_input(_event: InputEvent) -> void:
    pass

# player_idle.gd
class_name PlayerIdle
extends State
 
@export var player: Player
 
func enter(_msg: Dictionary = {}) -> void:
    player.animation.play("idle")
 
func physics_update(_delta: float) -> void:
    var direction := Input.get_vector("left", "right", "up", "down")
 
    if direction != Vector2.ZERO:
        state_machine.transition_to("Move")
 
func handle_input(event: InputEvent) -> void:
    if event.is_action_pressed("attack"):
        state_machine.transition_to("Attack")
    elif event.is_action_pressed("jump"):
        state_machine.transition_to("Jump")

# game_manager.gd (Add to Project Settings > Autoload)
extends Node
 
signal game_started
signal game_paused(is_paused: bool)
signal game_over(won: bool)
signal score_changed(new_score: int)
 
enum GameState { MENU, PLAYING, PAUSED, GAME_OVER }
 
var state: GameState = GameState.MENU
var score: int = 0:
    set(value):
        score = value
        score_changed.emit(score)
 
var high_score: int = 0
 
func _ready() -> void:
    process_mode = Node.PROCESS_MODE_ALWAYS
    _load_high_score()
 
func _input(event: InputEvent) -> void:
    if event.is_action_pressed("pause") and state == GameState.PLAYING:
        toggle_pause()
 
func start_game() -> void:
    score = 0
    state = GameState.PLAYING
    game_started.emit()
 
func toggle_pause() -> void:
    var is_paused := state != GameState.PAUSED
 
    if is_paused:
        state = GameState.PAUSED
        get_tree().paused = true
    else:
        state = GameState.PLAYING
        get_tree().paused = false
 
    game_paused.emit(is_paused)
 
func end_game(won: bool) -> void:
    state = GameState.GAME_OVER
 
    if score > high_score:
        high_score = score
        _save_high_score()
 
    game_over.emit(won)
 
func add_score(points: int) -> void:
    score += points
 
func _load_high_score() -> void:
    if FileAccess.file_exists("user://high_score.save"):
        var file := FileAccess.open("user://high_score.save", FileAccess.READ)
        high_score = file.get_32()
 
func _save_high_score() -> void:
    var file := FileAccess.open("user://high_score.save", FileAccess.WRITE)
    file.store_32(high_score)

# event_bus.gd (Global signal bus)
extends Node
 
# Player events
signal player_spawned(player: Node2D)
signal player_died(player: Node2D)
signal player_health_changed(health: int, max_health: int)
 
# Enemy events
signal enemy_spawned(enemy: Node2D)
signal enemy_died(enemy: Node2D, position: Vector2)
 
# Item events
signal item_collected(item_type: StringName, value: int)
signal powerup_activated(powerup_type: StringName)
 
# Level events
signal level_started(level_number: int)
signal level_completed(level_number: int, time: float)
signal checkpoint_reached(checkpoint_id: int)

# weapon_data.gd
class_name WeaponData
extends Resource
 
@export var name: StringName
@export var damage: int
@export var attack_speed: float
@export var range: float
@export_multiline var description: String
@export var icon: Texture2D
@export var projectile_scene: PackedScene
@export var sound_attack: AudioStream

# character_stats.gd
class_name CharacterStats
extends Resource
 
signal stat_changed(stat_name: StringName, new_value: float)
 
@export var max_health: float = 100.0
@export var attack: float = 10.0
@export var defense: float = 5.0
@export var speed: float = 200.0
 
# Runtime values (not saved)
var _current_health: float
 
func _init() -> void:
    _current_health = max_health
 
func get_current_health() -> float:
    return _current_health
 
func take_damage(amount: float) -> float:
    var actual_damage := maxf(amount - defense, 1.0)
    _current_health = maxf(_current_health - actual_damage, 0.0)
    stat_changed.emit("health", _current_health)
    return actual_damage
 
func heal(amount: float) -> void:
    _current_health = minf(_current_health + amount, max_health)
    stat_changed.emit("health", _current_health)
 
func duplicate_for_runtime() -> CharacterStats:
    var copy := duplicate() as CharacterStats
    copy._current_health = copy.max_health
    return copy

# Using resources
class_name Character
extends CharacterBody2D
 
@export var base_stats: CharacterStats
@export var weapon: WeaponData
 
var stats: CharacterStats
 
func _ready() -> void:
    # Create runtime copy to avoid modifying the resource
    stats = base_stats.duplicate_for_runtime()
    stats.stat_changed.connect(_on_stat_changed)
 
func attack() -> void:
    if weapon:
        print("Attacking with %s for %d damage" % [weapon.name, weapon.damage])
 
func _on_stat_changed(stat_name: StringName, value: float) -> void:
    if stat_name == "health" and value <= 0:
        die()

# object_pool.gd
class_name ObjectPool
extends Node
 
@export var pooled_scene: PackedScene
@export var initial_size: int = 10
@export var can_grow: bool = true
 
var _available: Array[Node] = []
var _in_use: Array[Node] = []
 
func _ready() -> void:
    _initialize_pool()
 
func _initialize_pool() -> void:
    for i in initial_size:
        _create_instance()
 
func _create_instance() -> Node:
    var instance := pooled_scene.instantiate()
    instance.process_mode = Node.PROCESS_MODE_DISABLED
    instance.visible = false
    add_child(instance)
    _available.append(instance)
 
    # Connect return signal if exists
    if instance.has_signal("returned_to_pool"):
        instance.returned_to_pool.connect(_return_to_pool.bind(instance))
 
    return instance
 
func get_instance() -> Node:
    var instance: Node
 
    if _available.is_empty():
        if can_grow:
            instance = _create_instance()
            _available.erase(instance)
        else:
            push_warning("Pool exhausted and cannot grow")
            return null
    else:
        instance = _available.pop_back()
 
    instance.process_mode = Node.PROCESS_MODE_INHERIT
    instance.visible = true
    _in_use.append(instance)
 
    if instance.has_method("on_spawn"):
        instance.on_spawn()
 
    return instance
 
func _return_to_pool(instance: Node) -> void:
    if not instance in _in_use:
        return
 
    _in_use.erase(instance)
 
    if instance.has_method("on_despawn"):
        instance.on_despawn()
 
    instance.process_mode = Node.PROCESS_MODE_DISABLED
    instance.visible = false
    _available.append(instance)
 
func return_all() -> void:
    for instance in _in_use.duplicate():
        _return_to_pool(instance)

# pooled_bullet.gd
class_name PooledBullet
extends Area2D
 
signal returned_to_pool
 
@export var speed: float = 500.0
@export var lifetime: float = 5.0
 
var direction: Vector2
var _timer: float
 
func on_spawn() -> void:
    _timer = lifetime
 
func on_despawn() -> void:
    direction = Vector2.ZERO
 
func initialize(pos: Vector2, dir: Vector2) -> void:
    global_position = pos
    direction = dir.normalized()
    rotation = direction.angle()
 
func _physics_process(delta: float) -> void:
    position += direction * speed * delta
 
    _timer -= delta
    if _timer <= 0:
        returned_to_pool.emit()
 
func _on_body_entered(body: Node2D) -> void:
    if body.has_method("take_damage"):
        body.take_damage(10)
    returned_to_pool.emit()

# health_component.gd
class_name HealthComponent
extends Node
 
signal health_changed(current: int, maximum: int)
signal damaged(amount: int, source: Node)
signal healed(amount: int)
signal died
 
@export var max_health: int = 100
@export var invincibility_time: float = 0.0
 
var current_health: int:
    set(value):
        var old := current_health
        current_health = clampi(value, 0, max_health)
        if current_health != old:
            health_changed.emit(current_health, max_health)
 
var _invincible: bool = false
 
func _ready() -> void:
    current_health = max_health
 
func take_damage(amount: int, source: Node = null) -> int:
    if _invincible or current_health <= 0:
        return 0
 
    var actual := mini(amount, current_health)
    current_health -= actual
    damaged.emit(actual, source)
 
    if current_health <= 0:
        died.emit()
    elif invincibility_time > 0:
        _start_invincibility()
 
    return actual