# 灵灯碰触流程重构

## Task 1: 灵灯只伤害第一个碰到的敌人

修改 `Assets/eco/SpiritLantern.cs` 的 `OnTriggerEnter`：

```csharp
private void OnTriggerEnter(Collider other)
{
    if (_recalled) return;  // 新增：已触发则忽略后续碰撞
    if (other.CompareTag("Player")) return;
    HealthSystem health = other.GetComponent<HealthSystem>();
    if (health != null)
    {
        health.Damage(damageOnContact);
        StartRecallSequence();  // 改名原 Recall()，改为协程流程
    }
}
```

## Task 2: 灵灯 2s 渐隐消失 + 灯光同步消失

修改 `Assets/eco/SpiritLantern.cs`，将 `Recall()` 改为分阶段流程：

```csharp
private void StartRecallSequence()
{
    if (_recalled) return;
    _recalled = true;
    // 1. 立即取消事件订阅 + 通知系统（回收灵灯名额）
    if (_ownerSystem != null) _ownerSystem.UnregisterLantern(this);
    OnLanternRecalled?.Invoke();
    OnLanternRecalled = null;
    // 2. 禁用碰撞体，开始 2s 渐隐
    GetComponent<Collider>().enabled = false;
    StartCoroutine(FadeOutAndDestroy(2f));
}

private IEnumerator FadeOutAndDestroy(float duration)
{
    var sr = GetComponent<SpriteRenderer>();
    var light = GetComponent<LightSource>();
    float startAlpha = sr != null ? sr.color.a : 1f;
    float startIntensity = light != null ? light.Intensity : 1f;
    float elapsed = 0f;
    while (elapsed < duration)
    {
        elapsed += Time.deltaTime;
        float t = elapsed / duration;
        if (sr != null)
            sr.color = new Color(sr.color.r, sr.color.g, sr.color.b, Mathf.Lerp(startAlpha, 0f, t));
        if (light != null)
            light.SetIntensity(Mathf.Lerp(startIntensity, 0f, t));
        yield return null;
    }
    Destroy(gameObject);
}
```

同时修改超时回收（`lifetime <= 0` 时）也走 `StartRecallSequence()` 而非直接销毁。

## Task 3: 敌人被灵灯杀死时的消失特效 + 魂灵掉落

修改 `Assets/eco/SpiritLantern.cs` 的 `OnTriggerEnter`，在调用 `health.Damage()` 之前读取敌人 maxHealth 并保存敌人位置：

```csharp
private void OnTriggerEnter(Collider other)
{
    if (_recalled) return;
    if (other.CompareTag("Player")) return;
    HealthSystem health = other.GetComponent<HealthSystem>();
    if (health != null)
    {
        // 在伤害前记录信息（用于掉落）
        Vector3 deathPos = other.transform.position;
        int enemyMaxHp = GetMaxHealth(health);
        health.Damage(damageOnContact);
        // 如果敌人死亡（血量<=0），生成魂灵掉落
        // 注意：Die() 会 Destroy gameObject，所以位置已提前保存
        if (health health <= 0) // 需要用反射或公开属性判断
            SpawnSoulDrops(deathPos, enemyMaxHp);
        StartRecallSequence();
    }
}
```

由于 `HealthSystem.health` 是 private，需要在 HealthSystem 中添加一个公开属性：

```csharp
// HealthSystem.cs 新增
public bool IsDead => _isDead;
public int MaxHealth => maxHealth;
```

然后改为：
```csharp
health.Damage(damageOnContact);
if (health.IsDead)
    SpawnSoulDrops(deathPos, health.MaxHealth);
```

## Task 4: 创建魂灵掉落物脚本 `SoulDrop.cs`

新建 `Assets/eco/SoulDrop.cs`：

```csharp
public class SoulDrop : MonoBehaviour
{
    [SerializeField] private float flyDuration = 0.8f;
    [SerializeField] private int scoreValue = 1;
    
    private RectTransform _targetUI; // HUD 魂灵图标位置
    
    public void Initialize(RectTransform targetUI)
    {
        _targetUI = targetUI;
        StartCoroutine(FlyToHUD());
    }
    
    private IEnumerator FlyToHUD()
    {
        Vector3 startPos = transform.position;
        // 获取目标屏幕位置
        Camera cam = Camera.main;
        Vector3 targetScreenPos = new Vector3(_targetUI.position.x, _targetUI.position.y, cam.WorldToScreenPoint(startPos).z);
        Vector3 targetWorldPos = cam.ScreenToWorldPoint(targetScreenPos);
        
        float elapsed = 0f;
        while (elapsed < flyDuration)
        {
            elapsed += Time.deltaTime;
            float t = elapsed / flyDuration;
            // 抛物线轨迹
            transform.position = Vector3.Lerp(startPos, targetWorldPos, t);
            transform.localScale = Vector3.one * (1f - t * 0.5f); // 缩小
            yield return null;
        }
        // 到达 HUD，加分
        if (ScoreManager.Instance != null)
            ScoreManager.Instance.AddScore(scoreValue);
        Destroy(gameObject);
    }
}
```

## Task 5: 魂灵掉落物生成逻辑

在 `SpiritLantern.cs` 中添加：

```csharp
[SerializeField] private GameObject soulDropPrefab;

private void SpawnSoulDrops(Vector3 position, int enemyMaxHp)
{
    int count = enemyMaxHp * Random.Range(2, 6); // 2~5倍
    RectTransform hudTarget = GameHUD.SoulIconRect; // 静态引用
    for (int i = 0; i < count; i++)
    {
        Vector3 offset = new Vector3(Random.Range(-0.3f, 0.3f), Random.Range(0f, 0.3f), Random.Range(-0.3f, 0.3f));
        GameObject drop = Instantiate(soulDropPrefab, position + offset, Quaternion.identity);
        SoulDrop soul = drop.GetComponent<SoulDrop>();
        if (soul != null)
            soul.Initialize(hudTarget);
    }
}
```

## Task 6: GameHUD 暴露魂灵图标 RectTransform

修改 `Assets/UI/GameHUD.cs`，添加静态引用：

```csharp
public static RectTransform SoulIconRect { get; private set; }

void Start()
{
    // ... 现有代码 ...
    if (soulIcon != null)
        SoulIconRect = soulIcon.rectTransform;
}
```

## Task 7: 创建魂灵掉落物预制体

- 创建一个小精灵 GameObject（SpriteRenderer + Collider2D trigger + SoulDrop 脚本）
- 保存为 `Assets/eco/Prefabs/SoulDrop.prefab`
- 将预制体引用赋给 SpiritLantern.prefab 的 `soulDropPrefab` 字段

## Task 8: 创建魂灵掉落物 Sprite 资源

- 使用 `ImageGen` 工具生成一个小光点/魂灵图标
- 导入 Unity 并赋给 SoulDrop.prefab 的 SpriteRenderer

---

## 涉及文件汇总

| 文件 | 修改类型 |
|------|---------|
| `Assets/eco/SpiritLantern.cs` | 重构碰撞+渐隐+掉落逻辑 |
| `Assets/2.5D Engine/Scripts/HealthSystem.cs` | 新增 `IsDead`、`MaxHealth` 公开属性 |
| `Assets/UI/GameHUD.cs` | 新增 `SoulIconRect` 静态属性 |
| `Assets/eco/SoulDrop.cs` | **新建** 魂灵掉落物脚本 |
| `Assets/eco/Prefabs/SoulDrop.prefab` | **新建** 魂灵掉落物预制体 |
| `Assets/eco/Prefabs/SpiritLantern.prefab` | 新增 `soulDropPrefab` 引用 |