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7. Boss战

EVOCOSMOS2026/4/14大约 7 分钟

7. 雷霆战机——Boss战

7.1 Boss战设计原则

Boss是每个关卡的高潮，一个好的Boss应该让玩家感到"好难但好爽"。设计Boss时需要遵循几个原则：

原则说明
阶段递进血量降低后攻击变强，让战斗有节奏感
弹幕公平再密集的弹幕也要有安全区域
弱点暴露某些时段不攻击或露出弱点，给玩家攻击窗口
视觉反馈Boss受伤、切换阶段时有明显提示
奖励丰厚击败Boss获得大量分数和道具

7.2 Boss血条系统

Boss需要一个醒目的血条，显示在屏幕顶部。

C
using Godot;

/// <summary>
/// Boss血条UI
/// </summary>
public partial class BossHealthBar : Control
{
    private ProgressBar _healthBar;
    private Label _bossNameLabel;
    private Label _hpLabel;
    private AnimationPlayer _animPlayer;

    private int _maxHP = 100;
    private int _currentHP = 100;

    public override void _Ready()
    {
        _healthBar = GetNode<ProgressBar>("HealthBar");
        _bossNameLabel = GetNode<Label>("BossName");
        _hpLabel = GetNode<Label>("HPLabel");
        _animPlayer = GetNode<AnimationPlayer>("AnimationPlayer");

        Visible = false;
    }

    /// <summary>
    /// 初始化Boss血条
    /// </summary>
    public void Initialize(string bossName, int maxHP)
    {
        _bossNameLabel.Text = bossName;
        _maxHP = maxHP;
        _currentHP = maxHP;

        _healthBar.MaxValue = maxHP;
        _healthBar.Value = maxHP;
        _hpLabel.Text = $"{maxHP} / {maxHP}";

        // 入场动画
        Visible = true;
        _animPlayer.Play("show");
    }

    /// <summary>
    /// 更新血条
    /// </summary>
    public void UpdateHP(int currentHP)
    {
        _currentHP = currentHP;
        _healthBar.Value = currentHP;
        _hpLabel.Text = $"{currentHP} / {_maxHP}";

        // 血量低于30%时血条变红
        float ratio = (float)currentHP / _maxHP;
        if (ratio < 0.3f)
        {
            _healthBar.SelfModulate = Colors.Red;
        }
        else if (ratio < 0.6f)
        {
            _healthBar.SelfModulate = Colors.Yellow;
        }
    }

    /// <summary>
    /// 隐藏血条
    /// </summary>
    public void HideBar()
    {
        _animPlayer.Play("hide");
        var timer = GetTree().CreateTimer(0.5f);
        timer.Timeout += () => Visible = false;
    }
}

7.3 Boss核心逻辑

Boss继承自Enemy基类，但增加了多阶段攻击和更复杂的行为。

C
using Godot;
using System.Collections.Generic;

/// <summary>
/// Boss——多阶段Boss
/// </summary>
public partial class Boss : Enemy
{
    // ===== Boss参数 =====
    [Export] public string BossName { get; set; } = "Boss";
    [Export] public int BossMaxHP { get; set; } = 200;

    // ===== 阶段系统 =====
    private int _currentPhase = 1;
    private int _maxPhases = 3;
    private float[] _phaseThresholds = { 1.0f, 0.6f, 0.3f };

    // ===== 攻击计时器 =====
    private float _attackTimer = 0f;
    private float _attackInterval = 1.5f;
    private int _attackPatternIndex = 0;

    // ===== 移动 =====
    private float _moveTimer = 0f;
    private Vector2 _targetPosition;

    // ===== 状态 =====
    private bool _isEntering = true;
    private float _enterTimer = 0f;
    private bool _isVulnerable = true;

    // ===== 引用 =====
    private BossHealthBar _healthBar;
    private Node2D _bulletContainer;
    private Area2D _player;

    public override void _Ready()
    {
        MaxHP = BossMaxHP;
        ScoreValue = 5000;
        DropChance = 1.0f; // Boss必掉道具
        MoveSpeed = 60f;

        base._Ready();

        _bulletContainer = GetParent()
            ?.GetParent()
            ?.GetNode<Node2D>("GameArea/EnemyBullets");
        _player = GetNodeOrNull<Area2D>(
            "/root/Main/GameArea/Player");
        _healthBar = GetNodeOrNull<BossHealthBar>(
            "/root/Main/HUD/BossHealthBar");

        // 初始位置：屏幕上方中间
        Position = new Vector2(
            GameConfig.ScreenWidth / 2f, -80f);
        _targetPosition = new Vector2(
            GameConfig.ScreenWidth / 2f, 80f);
    }

    public override void _Process(double delta)
    {
        if (_isEntering)
        {
            HandleEntry((float)delta);
            return;
        }

        if (!_alive) return;

        HandleMovement((float)delta);
        HandleAttack((float)delta);
    }

    /// <summary>
    /// Boss入场动画
    /// </summary>
    private void HandleEntry(float delta)
    {
        _enterTimer += delta;

        // 缓慢移动到目标位置
        Position = Position.Lerp(
            _targetPosition, 2f * delta);

        if (_enterTimer >= GameConfig.BossEntryDuration)
        {
            _isEntering = false;
            _healthBar?.Initialize(BossName, BossMaxHP);
        }
    }

    /// <summary>
    /// Boss移动——左右缓慢移动
    /// </summary>
    private void HandleMovement(float delta)
    {
        _moveTimer += delta;

        float margin = 60f;
        float minX = margin;
        float maxX = GameConfig.ScreenWidth - margin;

        // 阶段越高移动越快
        float speed = 40f + _currentPhase * 20f;

        Position += new Vector2(
            Mathf.Sin(_moveTimer * speed * 0.02f) * speed,
            0
        ) * delta;

        // 限制范围
        Position = new Vector2(
            Mathf.Clamp(Position.X, minX, maxX),
            Position.Y);
    }

    /// <summary>
    /// Boss攻击——根据阶段选择不同的弹幕模式
    /// </summary>
    private void HandleAttack(float delta)
    {
        _attackTimer += delta;

        float interval = Mathf.Max(0.3f,
            _attackInterval - _currentPhase * 0.3f);

        if (_attackTimer >= interval)
        {
            _attackTimer = 0f;
            ExecuteAttackPattern();
        }
    }

    /// <summary>
    /// 执行攻击模式
    /// </summary>
    private void ExecuteAttackPattern()
    {
        if (_player == null) return;

        switch (_currentPhase)
        {
            case 1:
                Phase1Attack();
                break;
            case 2:
                Phase2Attack();
                break;
            case 3:
                Phase3Attack();
                break;
        }

        _attackPatternIndex++;
    }

    /// <summary>
    /// 阶段1攻击——扇形散射
    /// </summary>
    private void Phase1Attack()
    {
        int bulletCount = 5;
        float spreadAngle = Mathf.Pi / 3f; // 60度扇形

        for (int i = 0; i < bulletCount; i++)
        {
            float angle = -spreadAngle / 2f
                + spreadAngle * i / (bulletCount - 1)
                + Mathf.Pi / 2f; // 向下

            var dir = new Vector2(Mathf.Cos(angle), Mathf.Sin(angle));
            FireBullet(dir, GameConfig.EnemyBulletSpeed,
                EnemyBullet.BulletType.Straight);
        }
    }

    /// <summary>
    /// 阶段2攻击——圆形弹幕+散射
    /// </summary>
    private void Phase2Attack()
    {
        if (_attackPatternIndex % 2 == 0)
        {
            // 圆形弹幕
            int bulletCount = 12;
            for (int i = 0; i < bulletCount; i++)
            {
                float angle = (Mathf.Tau * i) / bulletCount
                    + _attackPatternIndex * 0.3f;
                var bullet = GD.Load<PackedScene>(
                    "res://scenes/bullets/enemy_bullet.tscn")
                    .Instantiate<EnemyBullet>();
                bullet.InitCircular(GlobalPosition, angle,
                    GameConfig.EnemyBulletSpeed * 0.8f);
                _bulletContainer.AddChild(bullet);
            }
        }
        else
        {
            // 瞄准弹
            FireBullet(Vector2.Down, GameConfig.EnemyBulletSpeed * 1.2f,
                EnemyBullet.BulletType.Aimed);
        }
    }

    /// <summary>
    /// 阶段3攻击——疯狂模式
    /// </summary>
    private void Phase3Attack()
    {
        // 旋转弹幕
        int bulletCount = 16;
        float offset = _attackPatternIndex * 0.2f;
        for (int i = 0; i < bulletCount; i++)
        {
            float angle = (Mathf.Tau * i) / bulletCount + offset;
            var bullet = GD.Load<PackedScene>(
                "res://scenes/bullets/enemy_bullet.tscn")
                .Instantiate<EnemyBullet>();
            bullet.InitCircular(GlobalPosition, angle,
                GameConfig.EnemyBulletSpeed * 0.7f);
            _bulletContainer.AddChild(bullet);
        }

        // 追踪弹（每隔3次攻击发射一颗）
        if (_attackPatternIndex % 3 == 0)
        {
            var homingBullet = GD.Load<PackedScene>(
                "res://scenes/bullets/enemy_bullet.tscn")
                .Instantiate<EnemyBullet>();
            homingBullet.InitHoming(GlobalPosition, _player,
                GameConfig.EnemyBulletSpeed * 0.5f, 1.0f);
            _bulletContainer.AddChild(homingBullet);
        }
    }

    /// <summary>
    /// 重写受伤处理——加入阶段切换逻辑
    /// </summary>
    public override void TakeDamage(int damage)
    {
        if (!_isVulnerable) return;

        base.TakeDamage(damage);

        // 更新血条
        _healthBar?.UpdateHP(_currentHP);

        // 检查是否进入下一阶段
        float ratio = (float)_currentHP / BossMaxHP;
        int newPhase = 1;
        for (int i = _phaseThresholds.Length - 1; i >= 0; i--)
        {
            if (ratio <= _phaseThresholds[i])
            {
                newPhase = i + 1;
                break;
            }
        }

        if (newPhase > _currentPhase)
        {
            _currentPhase = newPhase;
            OnPhaseChange();
        }
    }

    /// <summary>
    /// 阶段切换
    /// </summary>
    private void OnPhaseChange()
    {
        GD.Print($"Boss进入阶段 {_currentPhase}");

        // 短暂无敌+特效
        _isVulnerable = false;
        var tween = CreateTween();

        // 闪烁效果
        for (int i = 0; i < 6; i++)
        {
            tween.TweenProperty(this, "modulate",
                new Color(1, 1, 1, 0.3f), 0.1f);
            tween.TweenProperty(this, "modulate",
                Colors.White, 0.1f);
        }

        tween.TweenCallback(Callable.From(() =>
        {
            _isVulnerable = true;
        }));
    }

    /// <summary>
    /// 重写死亡处理
    /// </summary>
    protected override void Die()
    {
        _healthBar?.HideBar();
        _gameManager?.AddScore(ScoreValue);

        // 大爆炸特效
        for (int i = 0; i < 5; i++)
        {
            var timer = GetTree().CreateTimer(i * 0.15f);
            timer.Timeout += () =>
            {
                SpawnExplosion();
                Position += new Vector2(
                    _random.Next(-30, 30),
                    _random.Next(-30, 30));
            };
        }

        // 屏幕震动
        ScreenShake.Shake(
            GameConfig.ScreenShakeOnBossDeath, 1.0f);

        // 掉落多个道具
        var powerUpMgr = GetNodeOrNull<PowerUpManager>(
            "/root/Main/PowerUpManager");
        if (powerUpMgr != null)
        {
            powerUpMgr.ForceDrop(GlobalPosition,
                PowerUp.PowerUpType.Power);
            powerUpMgr.ForceDrop(
                GlobalPosition + new Vector2(-30, 0),
                PowerUp.PowerUpType.Bomb);
            powerUpMgr.ForceDrop(
                GlobalPosition + new Vector2(30, 0),
                PowerUp.PowerUpType.Life);
        }

        // 延迟后销毁
        var destroyTimer = GetTree().CreateTimer(1.0f);
        destroyTimer.Timeout += () => QueueFree();

        _alive = false;
        Visible = false;
    }

    private Random _random = new();
}

7.4 Boss攻击模式总结

阶段血量范围攻击模式移动速度
1100%-60%5发扇形散射慢
260%-30%圆形弹幕+瞄准弹交替中
330%-0%16发旋转弹幕+追踪弹快

7.5 本章小结

组件说明
Boss血条顶部显示，带入场/退场动画
多阶段系统血量降低自动切换阶段
弹幕模式散射→圆形→旋转+追踪，递进加强
阶段切换闪烁特效+短暂无敌
Boss死亡多次爆炸+屏幕震动+大量道具掉落

下一章我们将搭建游戏UI界面。

最近更新:
贡献者: zefeng.peng,bobokaka
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