Test

Assets/Doc/浮漂.md

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+你这个现象（**两个角度来回切换/来回摆**）基本就是“**力矩过冲 + 阻尼施加方式不对**”导致的。
+
+我上一版里最明显的问题是：
+
+* **角阻尼 `AddTorque(-angularVelocity * …)` 被我放在每个采样点里执行了 n 次**
+  → 等于角阻尼被放大了 n 倍，而且随着浸没点数/深度变化，阻尼强度也在跳，容易出现“卡在两边来回抽”的感觉。
+* 浮力点离散 + 过强阻尼/过强浮力，很容易出现**过冲**，然后再被反向力矩拉回 → 看起来像两个角度之间来回切。
+
+下面我给你一个更稳的版本：
+✅ **浮力仍然按多点 AddForceAtPosition**（保证重心/姿态能自然翻正）
+✅ **角阻尼只加一次**（按总体浸没程度加）
+✅ 线性阻尼也更合理（仍然只阻尼“上浮方向分量”，但强度不乱跳）
+✅ 增加一个可选的 **“姿态稳定器 Upright Spring”**（很适合浮漂：会更快从躺漂回到竖漂，但不会锁死角度）
+
+---
+
+## CapsuleBuoyancyStable.cs（更稳定版）
+
+```csharp
+using UnityEngine;
+
+public interface IWaterProvider
+{
+    float GetWaterHeight(Vector3 worldPos);
+    Vector3 GetWaterNormal(Vector3 worldPos);
+    Vector3 GetWaterVelocity(Vector3 worldPos);
+}
+
+[DisallowMultipleComponent]
+[RequireComponent(typeof(Rigidbody), typeof(CapsuleCollider))]
+public class CapsuleBuoyancyStable : MonoBehaviour
+{
+    [Header("References")]
+    public MonoBehaviour WaterBehaviour; // 实现 IWaterProvider
+    private IWaterProvider Water => WaterBehaviour as IWaterProvider;
+
+    [Header("Buoyancy")]
+    [Tooltip("完全浸没时总浮力 = mass*g*buoyancyScale。>1 更浮。")]
+    public float buoyancyScale = 1.6f;
+
+    [Tooltip("沿胶囊轴向采样点数量（建议 7~11）。")]
+    [Range(3, 15)] public int samplePoints = 9;
+
+    [Tooltip("浸没比例曲线（0=刚碰水, 1=充分在水下）。")]
+    public AnimationCurve submergenceCurve = AnimationCurve.Linear(0, 0, 1, 1);
+
+    [Header("Damping")]
+    [Tooltip("上浮方向速度阻尼（越大越不弹）。")]
+    public float verticalDamping = 3.0f;
+
+    [Tooltip("整体角速度阻尼（只施加一次，不要太大）。")]
+    public float angularDamping = 0.6f;
+
+    [Header("Optional Upright Stabilizer (Recommended for bobber)")]
+    [Tooltip("让胶囊轴向更倾向于对齐世界Up。0=关闭。")]
+    public float uprightSpring = 0.0f;
+
+    [Tooltip("upright 的角速度阻尼。")]
+    public float uprightDamping = 0.5f;
+
+    [Tooltip("胶囊轴向：0=X,1=Y,2=Z（通常 CapsuleCollider.direction 也一样）。")]
+    public int uprightAxis = 1;
+
+    [Header("Water Drag")]
+    public float extraDragInWater = 0.8f;
+    public float extraAngularDragInWater = 0.8f;
+
+    [Header("Debug")]
+    public bool drawDebug = false;
+
+    Rigidbody _rb;
+    CapsuleCollider _cap;
+    float _baseDrag, _baseAngularDrag;
+
+    void Awake()
+    {
+        _rb = GetComponent<Rigidbody>();
+        _cap = GetComponent<CapsuleCollider>();
+        _baseDrag = _rb.drag;
+        _baseAngularDrag = _rb.angularDrag;
+
+        if (WaterBehaviour != null && Water == null)
+            Debug.LogError($"{name}: WaterBehaviour 没有实现 IWaterProvider。", this);
+    }
+
+    void FixedUpdate()
+    {
+        if (Water == null) return;
+
+        GetWorldCapsule(out Vector3 a, out Vector3 b, out float radius);
+
+        int n = Mathf.Max(3, samplePoints);
+        float fullBuoyancy = _rb.mass * Physics.gravity.magnitude * buoyancyScale;
+        float perPointMax = fullBuoyancy / n;
+
+        float subSum = 0f;
+        int wetCount = 0;
+
+        for (int i = 0; i < n; i++)
+        {
+            float t = (float)i / (n - 1);
+            Vector3 p = Vector3.Lerp(a, b, t);
+
+            float waterH = Water.GetWaterHeight(p);
+            float depth = waterH - p.y; // >0 在水下
+
+            float sub = Mathf.InverseLerp(-radius, radius, depth); // 0..1
+            if (sub <= 0f) continue;
+
+            sub = Mathf.Clamp01(submergenceCurve.Evaluate(sub));
+            subSum += sub;
+            wetCount++;
+
+            Vector3 buoyDir = Vector3.up;
+
+            Vector3 waterVel = Water.GetWaterVelocity(p);
+            Vector3 pointVel = _rb.GetPointVelocity(p);
+            Vector3 relVel = pointVel - waterVel;
+
+            // 浮力
+            Vector3 buoyForce = buoyDir * (perPointMax * sub);
+
+            // 只阻尼上浮方向速度分量（防弹跳）
+            float vUp = Vector3.Dot(relVel, buoyDir);
+            Vector3 dampForce = -buoyDir * (vUp * verticalDamping * _rb.mass * sub);
+
+            _rb.AddForceAtPosition(buoyForce + dampForce, p, ForceMode.Force);
+
+            if (drawDebug)
+            {
+                Debug.DrawLine(p, p + buoyForce / (_rb.mass * 10f), Color.cyan, 0f, false);
+                Debug.DrawLine(p, p + dampForce / (_rb.mass * 10f), Color.yellow, 0f, false);
+            }
+        }
+
+        float subAvg = (wetCount > 0) ? (subSum / wetCount) : 0f;
+
+        // 角阻尼：只加一次（关键修复点）
+        if (subAvg > 0f)
+        {
+            _rb.AddTorque(-_rb.angularVelocity * (angularDamping * _rb.mass * subAvg), ForceMode.Force);
+        }
+
+        // 可选：upright 稳定器（更像“浮漂自动立起来”）
+        if (subAvg > 0f && uprightSpring > 0f)
+        {
+            Vector3 axisWorld = GetAxisWorld(uprightAxis);
+            Vector3 targetUp = Vector3.up;
+
+            // 误差轴：axisWorld 需要对齐 targetUp（也可反过来按你浮漂模型选）
+            Vector3 errorAxis = Vector3.Cross(axisWorld, targetUp);
+            float errorMag = errorAxis.magnitude;
+
+            if (errorMag > 1e-6f)
+            {
+                errorAxis /= errorMag;
+
+                // “弹簧”力矩 + 阻尼（防止在两个角度间抽动）
+                Vector3 springTorque = errorAxis * (uprightSpring * errorMag * _rb.mass);
+                Vector3 dampTorque = -_rb.angularVelocity * (uprightDamping * _rb.mass);
+
+                _rb.AddTorque((springTorque + dampTorque) * subAvg, ForceMode.Force);
+            }
+        }
+
+        // 入水整体 drag
+        if (subAvg > 0.001f)
+        {
+            _rb.drag = _baseDrag + extraDragInWater * subAvg;
+            _rb.angularDrag = _baseAngularDrag + extraAngularDragInWater * subAvg;
+        }
+        else
+        {
+            _rb.drag = _baseDrag;
+            _rb.angularDrag = _baseAngularDrag;
+        }
+    }
+
+    Vector3 GetAxisWorld(int axis)
+    {
+        return axis switch
+        {
+            0 => transform.right,
+            2 => transform.forward,
+            _ => transform.up,
+        };
+    }
+
+    void GetWorldCapsule(out Vector3 a, out Vector3 b, out float radius)
+    {
+        Vector3 lossy = transform.lossyScale;
+        int dir = _cap.direction; // 0=X,1=Y,2=Z
+
+        float scaleAlong = (dir == 0) ? Mathf.Abs(lossy.x) : (dir == 1) ? Mathf.Abs(lossy.y) : Mathf.Abs(lossy.z);
+
+        float scaleR;
+        if (dir == 0) scaleR = Mathf.Max(Mathf.Abs(lossy.y), Mathf.Abs(lossy.z));
+        else if (dir == 1) scaleR = Mathf.Max(Mathf.Abs(lossy.x), Mathf.Abs(lossy.z));
+        else scaleR = Mathf.Max(Mathf.Abs(lossy.x), Mathf.Abs(lossy.y));
+
+        radius = _cap.radius * scaleR;
+
+        Vector3 center = transform.TransformPoint(_cap.center);
+        Vector3 axisWorld = (dir == 0) ? transform.right : (dir == 1) ? transform.up : transform.forward;
+
+        float heightWorld = Mathf.Max(0f, _cap.height * scaleAlong);
+        float cylinderLen = Mathf.Max(0f, heightWorld - 2f * radius);
+
+        Vector3 half = axisWorld * (cylinderLen * 0.5f);
+        a = center - half;
+        b = center + half;
+    }
+}
+```
+
+---
+
+## 你该怎么调（针对“两个角度来回变”）
+
+先用这组“稳的起步值”：
+
+* `samplePoints = 9`
+* `buoyancyScale = 1.4 ~ 2.2`
+* `verticalDamping = 2.0 ~ 6.0`（弹跳就加）
+* `angularDamping = 0.3 ~ 1.0`（摆动就加，但别太大）
+* 如果你是浮漂想要“自动立漂”：
+
+    * `uprightSpring = 0.5 ~ 3.0`
+    * `uprightDamping = 0.3 ~ 1.5`
+
+---
+
+## 额外一句：为什么 upright 会明显改善“两个角度抽动”
+
+纯“浮力点分布”产生的扶正力矩在水面附近会很敏感（浸没量一点点变化就翻转力矩方向），尤其你做的是**超小物体**，数值抖动更明显。upright 相当于给了一个“低频、连续”的姿态回正控制，配合阻尼，就不会在两个角度之间来回抽。
+
+如果你把你当前浮漂的 **CapsuleCollider 参数（height/radius/center/direction）+ Rigidbody mass + drag/angularDrag + 模型 pivot 在哪** 发我，我可以直接按你的尺度给一套“几乎不用调”的默认参数（针对 0.01 级尺寸那种）。

Assets/Doc/浮漂.md.meta

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