音效与视觉特效

皇牌空战的沉浸感很大程度来自音效：发动机的轰鸣随着油门变化、超音速时的音爆冲击、导弹击中时的爆炸声浪。本章实现让飞行体验栩栩如生的音效和视觉特效系统。

本章你将学到

• 发动机音效：随油门和速度动态变化
• 音速墙：突破音速（340m/s）时的视觉冲击波
• 导弹尾焰粒子特效
• 爆炸特效：飞机被击落的炫酷效果
• 机翼凝结尾迹（云迹）

发动机音效系统

发动机声音必须随油门、速度实时变化，才能有真实感：

GDScript

extends AudioStreamPlayer3D

## 发动机音效控制器
class_name EngineAudio

@export var min_pitch: float = 0.6      ## 慢车时的音调
@export var max_pitch: float = 1.6      ## 全油门时的音调
@export var afterburner_pitch: float = 2.0  ## 加力时的音调

@onready var aircraft: AircraftController = get_parent()

func _process(_delta: float) -> void:
    if not aircraft:
        return

    var target_pitch: float
    if aircraft.is_afterburner:
        target_pitch = afterburner_pitch
    else:
        # 根据油门线性插值音调
        target_pitch = lerp(min_pitch, max_pitch, aircraft.throttle)

    # 平滑过渡，避免音调跳变
    pitch_scale = lerp(pitch_scale, target_pitch, 0.1)

    # 音量也随油门变化
    volume_db = lerp(-10.0, 0.0, aircraft.throttle)

C

using Godot;

public partial class EngineAudio : AudioStreamPlayer3D
{
    [Export] public float MinPitch = 0.6f;
    [Export] public float MaxPitch = 1.6f;
    [Export] public float AfterburnerPitch = 2.0f;

    private AircraftController _aircraft;

    public override void _Ready()
    {
        _aircraft = GetParent<AircraftController>();
    }

    public override void _Process(double delta)
    {
        if (_aircraft == null) return;

        float targetPitch = _aircraft.IsAfterburner
            ? AfterburnerPitch
            : Mathf.Lerp(MinPitch, MaxPitch, _aircraft.Throttle);

        PitchScale = Mathf.Lerp(PitchScale, targetPitch, 0.1f);
        VolumeDb = Mathf.Lerp(-10f, 0f, _aircraft.Throttle);
    }
}

音速冲击波特效

当飞机速度超过340m/s（音速）时，产生锥形冲击波视觉效果：

GDScript

extends Node3D

## 音速冲击波特效
class_name SonicBoomEffect

## 音速（米/秒），实际游戏中可以调低让效果更频繁出现
const SOUND_SPEED := 340.0

@onready var cone_mesh: MeshInstance3D = $SonicConeMesh
@onready var aircraft: AircraftController = get_parent()

var is_supersonic: bool = false

func _process(delta: float) -> void:
    var speed := aircraft.airspeed
    var new_supersonic := speed > SOUND_SPEED

    if new_supersonic != is_supersonic:
        is_supersonic = new_supersonic
        cone_mesh.visible = is_supersonic
        if is_supersonic:
            _play_sonic_boom_sound()

    if is_supersonic:
        # 锥角随马赫数变化（速度越快锥角越小）
        var mach := speed / SOUND_SPEED
        var half_angle := asin(1.0 / mach)  ## 马赫锥半角
        cone_mesh.scale = Vector3(1.0, tan(half_angle) * 10.0, tan(half_angle) * 10.0)

func _play_sonic_boom_sound() -> void:
    pass  ## TODO: 播放音爆音效

C

using Godot;

public partial class SonicBoomEffect : Node3D
{
    private const float SoundSpeed = 340f;

    private MeshInstance3D _coneMesh;
    private AircraftController _aircraft;
    private bool _isSupersonic = false;

    public override void _Ready()
    {
        _coneMesh = GetNode<MeshInstance3D>("SonicConeMesh");
        _aircraft = GetParent<AircraftController>();
    }

    public override void _Process(double delta)
    {
        float speed = _aircraft.Airspeed;
        bool newSupersonic = speed > SoundSpeed;

        if (newSupersonic != _isSupersonic)
        {
            _isSupersonic = newSupersonic;
            _coneMesh.Visible = _isSupersonic;
            if (_isSupersonic) PlaySonicBoom();
        }

        if (_isSupersonic)
        {
            float mach = speed / SoundSpeed;
            float halfAngle = Mathf.Asin(1f / mach);
            float coneRadius = Mathf.Tan(halfAngle) * 10f;
            _coneMesh.Scale = new Vector3(1f, coneRadius, coneRadius);
        }
    }

    private void PlaySonicBoom() { /* TODO */ }
}

爆炸特效

被击落时的爆炸效果是玩家最后看到的画面，要足够震撼：

节点结构：

ExplosionEffect (Node3D)
├── Fireball (GPUParticles3D)      ← 火球（橙色/红色粒子）
├── Smoke (GPUParticles3D)         ← 浓烟（黑色粒子）
├── Debris (GPUParticles3D)        ← 碎片（灰色、棕色粒子）
├── ShockWave (MeshInstance3D)     ← 冲击波环（快速扩大的圆环）
└── ExplosionSound (AudioStreamPlayer3D)

机翼凝结尾迹

高速飞行时机翼尖端产生的白色水蒸气尾迹，是战斗机最标志性的视觉元素：

extends GPUParticles3D

## 凝结尾迹控制
class_name ContrailEffect

@export var min_altitude: float = 3000.0   ## 低于此高度不产生尾迹
@export var min_speed: float = 200.0       ## 低于此速度不产生尾迹

@onready var aircraft: AircraftController = get_parent().get_parent()

func _process(_delta: float) -> void:
    ## 只在高空高速时显示尾迹
    var show := aircraft.altitude > min_altitude and aircraft.airspeed > min_speed
    emitting = show

下一步

音效和特效完成后，进入 打磨与发布。