UI、音频与游戏流程

[node name="RightPanel" type="PanelContainer" parent="."]
anchors_preset = 11
anchor_left = 1.0
anchor_right = 1.0
anchor_bottom = 1.0
offset_left = -180.0
grow_horizontal = 0
grow_vertical = 2
theme_type_variation = &"HudPanel"

[resource]
default_font = ExtResource("font")
default_font_size = 18
Button/colors/font_color = Color(0.82, 0.9, 1, 1)
Button/colors/font_hover_color = Color(1, 1, 1, 1)
Button/colors/font_pressed_color = Color(0.02, 0.05, 0.1, 1)
Button/colors/font_focus_color = Color(1, 1, 1, 1)
Button/colors/font_hover_pressed_color = Color(0.02, 0.05, 0.1, 1)
Button/colors/font_disabled_color = Color(0.4, 0.45, 0.55, 1)
Button/font_sizes/font_size = 20
Button/styles/normal = SubResource("btn_normal")
Button/styles/hover = SubResource("btn_hover")
Button/styles/pressed = SubResource("btn_pressed")
Button/styles/hover_pressed = SubResource("btn_pressed")
Button/styles/disabled = SubResource("btn_disabled")
Button/styles/focus = SubResource("btn_focus")
DangerButton/base_type = &"Button"
DangerButton/styles/normal = SubResource("danger_normal")
DangerButton/styles/hover = SubResource("danger_hover")
Label/colors/font_color = Color(0.85, 0.92, 1, 1)
Label/colors/font_shadow_color = Color(0, 0, 0, 0.6)
Label/constants/shadow_offset_x = 0

[sub_resource type="StyleBoxFlat" id="btn_focus"]
content_margin_left = 16.0
content_margin_top = 8.0
content_margin_right = 16.0
content_margin_bottom = 8.0
draw_center = false
border_width_left = 2
border_width_top = 2
border_width_right = 2
border_width_bottom = 2
border_color = Color(1, 0.35, 0.8, 1)
corner_radius_top_left = 8

TitleLabel/base_type = &"Label"
TitleLabel/colors/font_color = Color(0.55, 1.7, 2.3, 1)
TitleLabel/colors/font_shadow_color = Color(1, 0.2, 0.7, 0.55)
TitleLabel/constants/shadow_offset_x = 3
TitleLabel/constants/shadow_offset_y = 3
TitleLabel/font_sizes/font_size = 60

## 鼠标移到按钮上时也把焦点给它，这样鼠标、键盘、手柄三种操作的"当前项"始终是同一个。
func _on_button_hover(b: Button) -> void:
	b.grab_focus()

func start_game(at_boss := false) -> void:
	start_at_boss = at_boss
	get_tree().paused = false
	Audio.set_muffled(false)
	_set_state(State.PLAYING)
	# change_scene_to_file 会在本帧结束时释放旧场景、加载新场景，
	# 旧场景里的节点（包括它们的 Tuning 绑定、信号连接）都会跟着消失。
	get_tree().change_scene_to_file(GAME_SCENE)


func go_to_title() -> void:
	get_tree().paused = false
	Audio.set_muffled(false)
	_set_state(State.TITLE)
	get_tree().change_scene_to_file(TITLE_SCENE)

[node name="PauseMenu" type="CanvasLayer"]
process_mode = 2
layer = 10
script = ExtResource("1")

func set_paused(paused: bool) -> void:
	if state != State.PLAYING and state != State.PAUSED:
		return
	# get_tree().paused 会停掉所有 process_mode 为 INHERIT/PAUSABLE 的节点：
	# _process、_physics_process、物理、动画、计时器（create_timer 的 process_always=false 时）都停。
	# 暂停菜单把自己设成 WHEN_PAUSED，Flow 和 Audio 是 ALWAYS，所以它们还能动。
	get_tree().paused = paused
	Audio.set_muffled(paused)
	_set_state(State.PAUSED if paused else State.PLAYING)


func _unhandled_input(event: InputEvent) -> void:
	if event.is_action_pressed("pause"):
		set_paused(state == State.PLAYING)
		get_viewport().set_input_as_handled()

[gd_resource type="AudioBusLayout" format=3 uid="uid://bgrbiwgujfvx0"]

[sub_resource type="AudioEffectHardLimiter" id="limiter"]
resource_name = "HardLimiter"
ceiling_db = -0.5

[sub_resource type="AudioEffectLowPassFilter" id="music_lowpass"]
resource_name = "LowPassFilter"
cutoff_hz = 20000.0

[sub_resource type="AudioEffectCompressor" id="sfx_comp"]
resource_name = "Compressor"
threshold = -14.0
ratio = 3.0

[resource]
bus/0/effect/0/effect = SubResource("limiter")
bus/0/effect/0/enabled = true
bus/1/name = &"Music"
bus/1/solo = false
bus/1/mute = false
bus/1/bypass_fx = false
bus/1/volume_db = 0.0
bus/1/send = &"Master"
bus/1/effect/0/effect = SubResource("music_lowpass")
bus/1/effect/0/enabled = true
bus/2/name = &"SFX"
bus/2/solo = false
bus/2/mute = false
bus/2/bypass_fx = false
bus/2/volume_db = 0.0
bus/2/send = &"Master"
bus/2/effect/0/effect = SubResource("sfx_comp")
bus/2/effect/0/enabled = true

## 暂停时把音乐"闷"住：打开 Music 总线上的低通滤波器，并压低音量。
## 低通是总线效果器，Web 默认的 Sample 播放模式不支持效果器，所以再叠一个降音量，两边都能听出变化。
func set_muffled(on: bool) -> void:
	_muffled = on
	var bus := AudioServer.get_bus_index(&"Music")
	var lowpass := AudioServer.get_bus_effect(bus, 0) as AudioEffectLowPassFilter
	lowpass.cutoff_hz = 900.0 if on else 20000.0
	music_volume = music_volume      # 重新走一遍 setter，按 _muffled 算音量

## 播放一个非定位音效（射击、拾取、UI）。
func play(sfx_name: String, volume_db := 0.0) -> void:
	var p: AudioStreamPlayer = _players.get(sfx_name)
	if p == null:
		return
	_plays_counter += 1
	p.volume_db = volume_db
	# 随机音高：同一个声音连发几十次也不会像"机关枪录音"。
	# 注意 pitch_scale 是整个节点的属性，会影响它正在响的其他声部；短音效听不出来。
	p.pitch_scale = 1.0 + randf_range(-random_pitch, random_pitch)
	p.play()     # max_polyphony > 1 时，play() 会新开一个声部；满了就掐掉最老的


## 在某个位置播放（爆炸）。AudioStreamPlayer2D 会根据它和摄像机的相对位置算左右声像和衰减。
func play_at(sfx_name: String, global_pos: Vector2, volume_db := 0.0) -> void:
	_plays_counter += 1
	var p := _voices_2d[_next_voice]
	_next_voice = (_next_voice + 1) % _voices_2d.size()   # 轮流使用，最老的被复用
	p.stream = SFX[sfx_name]
	p.global_position = global_pos
	p.volume_db = volume_db
	p.pitch_scale = 1.0 + randf_range(-random_pitch, random_pitch)
	p.play()

def osc(kind, freq, n, sr=SR):
    """振荡器。freq 可以是常数，也可以是逐采样的数组（用来做音高滑动）。
    相位 = 频率的累加，所以变频时波形是连续的，不会"咔哒"响。"""
    f = np.broadcast_to(np.asarray(freq, dtype=float), (n,))
    phase = np.cumsum(f / sr) % 1.0
    if kind == "sine":
        return np.sin(2 * np.pi * phase)
    if kind == "square":
        return np.where(phase < 0.5, 1.0, -1.0)
    if kind == "saw":
        return 2 * phase - 1
    if kind == "triangle":
        return 1 - 4 * np.abs(phase - 0.5)
    if kind == "noise":
        return rng.uniform(-1, 1, n)
    raise ValueError(kind)

def adsr(n, a, d, s, r, sr=SR):
    """ADSR 包络：起音 a 秒升到 1 → 衰减 d 秒降到持续电平 s → 保持 → 最后 r 秒释放到 0。
    n 是总采样数；返回长度为 n 的增益曲线。"""
    A, D, R = int(a * sr), int(d * sr), int(r * sr)
    S = max(0, n - A - D - R)                       # 持续段占剩下的时间
    env = np.concatenate([
        np.linspace(0, 1, A, endpoint=False),        # Attack
        np.linspace(1, s, D, endpoint=False),        # Decay
        np.full(S, s),                               # Sustain
        np.linspace(s, 0, R),                        # Release
    ])
    return np.pad(env, (0, max(0, n - len(env))))[:n]

def make_shoot():
    n = sec(0.09)
    tone = osc("square", sweep(1400, 520, n, 0.6), n) * 0.5 + osc("noise", 0, n) * 0.15
    return tone * adsr(n, 0.002, 0.04, 0.25, 0.04)


def make_explosion(length=0.55, low=55):
    n = sec(length)
    noise = lowpass(osc("noise", 0, n), sweep(5000, 180, n, 0.5))
    thump = osc("sine", sweep(160, low, n, 0.4), n)
    return (noise * 1.2 + thump * 0.9) * adsr(n, 0.003, length * 0.35, 0.35, length * 0.6)


def make_pickup():
    notes = [523.25, 659.25, 783.99, 1046.5]          # C5 E5 G5 C6 琶音
    parts = []
    for f in notes:
        n = sec(0.065)
        parts.append((osc("square", f, n) * 0.4 + osc("sine", f * 2, n) * 0.3) * adsr(n, 0.002, 0.03, 0.6, 0.02))
    return np.concatenate(parts)


def make_hurt():
    n = sec(0.42)
    tone = osc("saw", sweep(520, 70, n, 0.7), n) * 0.7 + osc("noise", 0, n) * 0.25
    return lowpass(tone, 2400) * adsr(n, 0.004, 0.12, 0.5, 0.25)


def make_enemy_shot():
    n = sec(0.07)
    return osc("triangle", sweep(900, 600, n), n) * adsr(n, 0.002, 0.03, 0.3, 0.03)


def make_ui_move():
    n = sec(0.035)
    return osc("square", 1200, n) * adsr(n, 0.001, 0.015, 0.2, 0.015)


def make_ui_ok():
    a, b = sec(0.06), sec(0.11)
    return np.concatenate([osc("square", 880, a) * adsr(a, 0.001, 0.02, 0.6, 0.02),
                           osc("square", 1320, b) * adsr(b, 0.001, 0.03, 0.5, 0.07)])

## 浏览器的自动播放策略：用户和页面交互之前，声音不允许播放。
## Godot 收到第一次输入时会恢复 AudioContext；这里也等到那一刻再开始放音乐，
## 这样玩家不会错过开头，也不会在后台"无声地"播完前奏。
func play_music() -> void:
	_want_music = true
	if _unlocked and not _music.playing:
		_music.play()


func _input(event: InputEvent) -> void:
	if _unlocked:
		return
	if (event is InputEventKey or event is InputEventMouseButton or event is InputEventJoypadButton
			or event is InputEventScreenTouch) and event.is_pressed():
		_unlocked = true
		if _want_music:
			_music.play()

## 存档用 ConfigFile（INI 格式的文本）。user:// 在桌面上是系统的应用数据目录，
## 在 Web 上是浏览器的 IndexedDB——刷新页面后还在，换浏览器或清除网站数据就没了。
func save() -> void:
	var cfg := ConfigFile.new()
	cfg.set_value("scores", "list", high_scores)
	cfg.set_value("audio", "music_volume", Audio.music_volume)
	cfg.set_value("audio", "sfx_volume", Audio.sfx_volume)
	var err := cfg.save(SAVE_PATH)
	if err != OK:
		push_warning("存档失败：%s" % error_string(err))


func load_save() -> void:
	var cfg := ConfigFile.new()
	if cfg.load(SAVE_PATH) != OK:
		return      # 第一次运行，还没有存档
	high_scores.assign(cfg.get_value("scores", "list", []))
	Audio.music_volume = cfg.get_value("audio", "music_volume", Audio.music_volume)
	Audio.sfx_volume = cfg.get_value("audio", "sfx_volume", Audio.sfx_volume)