Godot4 全场景切换方案

extends Button # 菜单按钮脚本

func _pressed():
    # 切换到游戏关卡场景，同步加载，大场景会卡顿
    get_tree().change_scene_to_file("res://scenes/level_01.tscn")

# 全局预加载关卡，编译期载入，切换零卡顿
const LEVEL1: PackedScene = preload("res://scenes/level_01.tscn")

func switch_level():
    get_tree().change_scene_to_packed(LEVEL1)

# GameManager.gd 全局自动加载单例
var player_hp: int
var current_stage: int

# 切换前赋值
GameManager.current_stage = 1
get_tree().change_scene_to_file("res://scenes/level_01.tscn")

# 新场景_ready读取
func _ready():
    print("当前关卡：", GameManager.current_stage)

# 创建临时数据节点，新场景读取后销毁
var data_node = Node()
data_node.set_name("TempData")
data_node.set_meta("hp", 80)
get_tree().root.add_child(data_node)

get_tree().change_scene_to_file("res://scenes/level_01.tscn")

# 新场景读取
func _ready():
    var temp_data = get_tree().root.get_node_or_null("TempData")
    if temp_data:
        var hp = temp_data.get_meta("hp")
        temp_data.queue_free() # 用完销毁

extends Control # 加载界面脚本
@export var progress_bar: ProgressBar
var task_id: int = -1
var target_scene_path: String = "res://scenes/big_world.tscn"

func _ready():
    # 监听资源加载完成信号
    ResourceLoader.resource_load_completed.connect(_on_scene_loaded)
    # 开启子线程异步加载场景
    task_id = ResourceLoader.load_threaded(target_scene_path, PackedScene, true)
    await _process_frame
    _update_progress()

# 轮询更新加载进度条
func _update_progress():
    if task_id == -1: return
    var status = ResourceLoader.get_load_thread_status(task_id)
    var progress = ResourceLoader.get_load_thread_progress(task_id)
    progress_bar.value = progress * 100

    match status:
        0: # 加载中，继续循环
            await _process_frame
            _update_progress()
        1: # 加载完成，等待回调
            pass
        2: # 加载失败
            print("场景加载失败！")

# 资源加载完成回调，执行场景切换
func _on_scene_loaded(path: String, scene_res: Resource, err: int):
    if err != 0 or path != target_scene_path or scene_res == null:
        return
    # 替换根场景，进入新关卡
    get_tree().change_scene_to_packed(scene_res as PackedScene)

const UI_POPUP: PackedScene = preload("res://ui/shop_popup.tscn")

# 打开商店弹窗，原场景保留
func open_shop():
    var popup = UI_POPUP.instantiate()
    # 加到根节点，全屏覆盖UI
    get_tree().root.add_child(popup)

# 关闭弹窗（销毁叠加场景）
func close_shop(popup_node: Node):
    popup_node.queue_free()

# 父节点为 SceneLayerManager（放根节点下）
var battle_layer: Node3D = $SceneLayerManager/BattleLayer

func enter_battle():
    var battle_scene = preload("res://scenes/battle.tscn").instantiate()
    battle_layer.add_child(battle_scene)

# 清空所有战斗内容
func exit_battle():
    battle_layer.queue_free_children()

extends Node3D
var next_level_scene: PackedScene = null
var load_task: int = -1

func _ready():
    # 后台异步预加载下一关，不阻塞游戏
    load_task = ResourceLoader.load_threaded("res://scenes/level_02.tscn", PackedScene, true)
    ResourceLoader.resource_load_completed.connect(_preload_finish)

# 预加载完成缓存场景
func _preload_finish(path, res, err):
    if err == 0:
        next_level_scene = res as PackedScene
        print("下一关预加载完成，可无缝切换")

# 玩家触发切换关卡
func switch_next_level():
    if next_level_scene != null:
        get_tree().change_scene_to_packed(next_level_scene)
    else:
        # 预加载没完成，走同步加载兜底
        get_tree().change_scene_to_file("res://scenes/level_02.tscn")

const SHOP_SCENE: PackedScene = preload("res://ui/shop.tscn")
var shop_instance: Control

func _ready():
    # 提前实例化，默认隐藏
    shop_instance = SHOP_SCENE.instantiate()
    shop_instance.visible = false
    get_tree().root.add_child(shop_instance)

# 打开商店
func open_shop():
    shop_instance.visible = true
    shop_instance.process_mode = Node.PROCESS_MODE_INHERIT

# 关闭商店（不销毁，下次直接显示）
func close_shop():
    shop_instance.visible = false
    shop_instance.process_mode = Node.PROCESS_MODE_DISABLED # 停止逻辑节省性能

func restart_level():
    get_tree().reload_current_scene()

var current_path = get_tree().current_scene.resource_path
print("当前场景：", current_path)

func switch_and_do_something():
    get_tree().change_scene_to_file("res://level_02.tscn")
    await get_tree().scene_changed # 等待场景切换完成信号
    print("新场景加载完毕，执行初始化逻辑")

# 全局GameManager脚本
func _enter_tree():
    get_tree().scene_changed.connect(_on_scene_switch)

func _on_scene_switch(new_scene: Node):
    print("切换到新场景：", new_scene.name)
    AudioServer.stop_all_streams() # 停止旧场景音乐

# 过渡黑屏脚本
func fade_out():
    var tween = create_tween()
    tween.tween_property(self, "modulate:a", 0, 0.5)
    await tween.finished
    queue_free()