Godot4 资源加载

extends Node3D

# 导出资源类型，编辑器拖拽赋值，【静态加载】
@export var player_scene: PackedScene       # 角色场景
@export var sound_jump: AudioStream         # 跳跃音效
@export var tex_body: Texture2D             # 角色贴图
@export var mat_metal: StandardMaterial3D   # 材质资源

func _ready():
    # 直接使用，无需加载代码，资源已经就绪
    $AudioStreamPlayer.stream = sound_jump

# 全局作用域，编译期静态加载
const BULLET_SCENE: PackedScene = preload("res://scenes/bullet.tscn")
const ICON_TEX: Texture2D = preload("res://textures/icon.png")

extends Node3D

# 1. 预加载场景文件【最常用】
const PLAYER_SCENE: PackedScene = preload("res://scenes/player.tscn")
# 2. 预加载贴图资源
const PLAYER_TEX: Texture2D = preload("res://textures/player.png")
# 3. 预加载音频
const JUMP_SOUND: AudioStream = preload("res://sounds/jump.wav")
# 4. 预加载材质
const RED_MAT: StandardMaterial3D = preload("res://materials/red_mat.tres")
# 5. 预加载GDScript脚本
const SKILL_SCRIPT: GDScript = preload("res://scripts/skill.gd")
# 6. 预加载动画资源
const IDLE_ANIM: Animation = preload("res://animations/idle.anim")

func _ready():
    # 直接实例化、使用，无任何加载延迟
    var player = PLAYER_SCENE.instantiate()
    add_child(player)

    # 赋值材质
    $MeshInstance3D.material_override = RED_MAT

extends Node3D

func _ready():
    # 1. 动态拼接路径，加载不同皮肤贴图【preload做不到】
    var skin_id = 2
    var tex_path = "res://textures/skin_%d.png" % skin_id
    var skin_tex: Texture2D = load(tex_path)
    $MeshInstance3D.texture_override = skin_tex

    # 2. 动态加载场景
    var enemy_scene: PackedScene = load("res://scenes/enemy_01.tscn")
    add_child(enemy_scene.instantiate())

    # 3. 动态加载脚本并附加
    var runtime_script: GDScript = load("res://scripts/buff.gd")
    $Player.set_script(runtime_script)

    # 4. 容错写法（防止资源不存在崩溃）
    var safe_res = load("res://textures/null.png")
    if safe_res != null:
        print("资源加载成功")
    else:
        print("资源缺失")

extends Node3D

# 存储加载任务ID
var load_task_id: int = -1

func _ready():
    # 绑定全局资源加载完成信号
    ResourceLoader.resource_load_completed.connect(_on_resource_loaded)

    # 启动异步加载：加载巨型场景+高清贴图
    # 参数1：资源路径 参数2：资源类型 参数3：子线程加载
    load_task_id = ResourceLoader.load_threaded(
        "res://scenes/big_map.tscn",
        PackedScene,
        true
    )

    # 开启进度检测
    await _process_frame
    _check_load_progress()

# 轮询加载进度，更新UI进度条
func _check_load_progress() -> void:
    if load_task_id == -1:
        return
    # 获取加载状态：0加载中 1完成 2失败
    var status = ResourceLoader.get_load_thread_status(load_task_id)
    var progress = ResourceLoader.get_load_thread_progress(load_task_id)
    print("地图加载进度：", progress * 100, "%")

    match status:
        0:
            await _process_frame
            _check_load_progress()
        1:
            print("加载完成，等待回调")
        2:
            print("资源加载失败、路径错误")

# 资源加载完成回调
func _on_resource_loaded(path: String, res: Resource, error: int) -> void:
    if error != 0 or res == null:
        print("加载异常")
        return

    # 实例化加载完成的大场景
    if path == "res://scenes/big_map.tscn":
        var map_scene = res as PackedScene
        add_child(map_scene.instantiate())

# 读取用户存档目录图片
var save_tex = load("user://save_texture.png")

# 加载json配置
var json_res: FileAccess = load("res://config/setting.json")
var json_data = JSON.parse(json_res.get_as_text())

# 清理指定资源缓存
ResourceCache.remove("res://textures/old_skin.png")
# 清空全部资源缓存
ResourceCache.clear()

# 第二个参数开启忽略缺失报错
var optional_sound = preload("res://sound/vip.wav", true)