238 lines
8.5 KiB
Markdown
238 lines
8.5 KiB
Markdown
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。
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我上一版里最明显的问题是：
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* **角阻尼 `AddTorque(-angularVelocity * …)` 被我放在每个采样点里执行了 n 次**
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→ 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。
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* 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。
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下面我给你一个更稳的版本：
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✅ **浮力仍然按多点 AddForceAtPosition**（保证重心/姿态能自然翻正）
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✅ **角阻尼只加一次**（按总体浸没程度加）
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✅ 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）
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✅ 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）
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---
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## CapsuleBuoyancyStable.cs（更稳定版）
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```csharp
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using UnityEngine;
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public interface IWaterProvider
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{
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float GetWaterHeight(Vector3 worldPos);
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Vector3 GetWaterNormal(Vector3 worldPos);
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Vector3 GetWaterVelocity(Vector3 worldPos);
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}
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[DisallowMultipleComponent]
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[RequireComponent(typeof(Rigidbody), typeof(CapsuleCollider))]
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public class CapsuleBuoyancyStable : MonoBehaviour
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{
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[Header("References")]
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public MonoBehaviour WaterBehaviour; // 实现 IWaterProvider
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private IWaterProvider Water => WaterBehaviour as IWaterProvider;
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[Header("Buoyancy")]
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[Tooltip("完全浸没时总浮力 = mass*g*buoyancyScale。>1 更浮。")]
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public float buoyancyScale = 1.6f;
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[Tooltip("沿胶囊轴向采样点数量（建议 7~11）。")]
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[Range(3, 15)] public int samplePoints = 9;
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[Tooltip("浸没比例曲线（0=刚碰水, 1=充分在水下）。")]
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public AnimationCurve submergenceCurve = AnimationCurve.Linear(0, 0, 1, 1);
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[Header("Damping")]
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[Tooltip("上浮方向速度阻尼（越大越不弹）。")]
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public float verticalDamping = 3.0f;
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[Tooltip("整体角速度阻尼（只施加一次，不要太大）。")]
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public float angularDamping = 0.6f;
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[Header("Optional Upright Stabilizer (Recommended for bobber)")]
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[Tooltip("让胶囊轴向更倾向于对齐世界Up。0=关闭。")]
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public float uprightSpring = 0.0f;
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[Tooltip("upright 的角速度阻尼。")]
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public float uprightDamping = 0.5f;
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[Tooltip("胶囊轴向：0=X,1=Y,2=Z（通常 CapsuleCollider.direction 也一样）。")]
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public int uprightAxis = 1;
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[Header("Water Drag")]
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public float extraDragInWater = 0.8f;
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public float extraAngularDragInWater = 0.8f;
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[Header("Debug")]
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public bool drawDebug = false;
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Rigidbody _rb;
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CapsuleCollider _cap;
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float _baseDrag, _baseAngularDrag;
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void Awake()
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{
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_rb = GetComponent<Rigidbody>();
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_cap = GetComponent<CapsuleCollider>();
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_baseDrag = _rb.drag;
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_baseAngularDrag = _rb.angularDrag;
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if (WaterBehaviour != null && Water == null)
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Debug.LogError($"{name}: WaterBehaviour 没有实现 IWaterProvider。", this);
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}
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void FixedUpdate()
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{
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if (Water == null) return;
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GetWorldCapsule(out Vector3 a, out Vector3 b, out float radius);
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int n = Mathf.Max(3, samplePoints);
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float fullBuoyancy = _rb.mass * Physics.gravity.magnitude * buoyancyScale;
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float perPointMax = fullBuoyancy / n;
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float subSum = 0f;
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int wetCount = 0;
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for (int i = 0; i < n; i++)
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{
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float t = (float)i / (n - 1);
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Vector3 p = Vector3.Lerp(a, b, t);
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float waterH = Water.GetWaterHeight(p);
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float depth = waterH - p.y; // >0 在水下
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float sub = Mathf.InverseLerp(-radius, radius, depth); // 0..1
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if (sub <= 0f) continue;
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sub = Mathf.Clamp01(submergenceCurve.Evaluate(sub));
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subSum += sub;
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wetCount++;
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Vector3 buoyDir = Vector3.up;
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Vector3 waterVel = Water.GetWaterVelocity(p);
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Vector3 pointVel = _rb.GetPointVelocity(p);
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Vector3 relVel = pointVel - waterVel;
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// 浮力
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Vector3 buoyForce = buoyDir * (perPointMax * sub);
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// 只阻尼上浮方向速度分量（防弹跳）
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float vUp = Vector3.Dot(relVel, buoyDir);
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Vector3 dampForce = -buoyDir * (vUp * verticalDamping * _rb.mass * sub);
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_rb.AddForceAtPosition(buoyForce + dampForce, p, ForceMode.Force);
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if (drawDebug)
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{
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Debug.DrawLine(p, p + buoyForce / (_rb.mass * 10f), Color.cyan, 0f, false);
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Debug.DrawLine(p, p + dampForce / (_rb.mass * 10f), Color.yellow, 0f, false);
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}
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}
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float subAvg = (wetCount > 0) ? (subSum / wetCount) : 0f;
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// 角阻尼：只加一次（关键修复点）
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if (subAvg > 0f)
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{
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_rb.AddTorque(-_rb.angularVelocity * (angularDamping * _rb.mass * subAvg), ForceMode.Force);
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}
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// 可选：upright 稳定器（更像“浮漂自动立起来”）
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if (subAvg > 0f && uprightSpring > 0f)
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{
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Vector3 axisWorld = GetAxisWorld(uprightAxis);
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Vector3 targetUp = Vector3.up;
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// 误差轴：axisWorld 需要对齐 targetUp（也可反过来按你浮漂模型选）
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Vector3 errorAxis = Vector3.Cross(axisWorld, targetUp);
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float errorMag = errorAxis.magnitude;
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if (errorMag > 1e-6f)
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{
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errorAxis /= errorMag;
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// “弹簧”力矩 + 阻尼（防止在两个角度间抽动）
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Vector3 springTorque = errorAxis * (uprightSpring * errorMag * _rb.mass);
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Vector3 dampTorque = -_rb.angularVelocity * (uprightDamping * _rb.mass);
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_rb.AddTorque((springTorque + dampTorque) * subAvg, ForceMode.Force);
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}
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}
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// 入水整体 drag
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if (subAvg > 0.001f)
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{
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_rb.drag = _baseDrag + extraDragInWater * subAvg;
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_rb.angularDrag = _baseAngularDrag + extraAngularDragInWater * subAvg;
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}
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else
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{
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_rb.drag = _baseDrag;
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_rb.angularDrag = _baseAngularDrag;
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}
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}
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Vector3 GetAxisWorld(int axis)
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{
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return axis switch
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{
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0 => transform.right,
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2 => transform.forward,
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_ => transform.up,
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};
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}
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void GetWorldCapsule(out Vector3 a, out Vector3 b, out float radius)
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{
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Vector3 lossy = transform.lossyScale;
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int dir = _cap.direction; // 0=X,1=Y,2=Z
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float scaleAlong = (dir == 0) ? Mathf.Abs(lossy.x) : (dir == 1) ? Mathf.Abs(lossy.y) : Mathf.Abs(lossy.z);
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float scaleR;
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if (dir == 0) scaleR = Mathf.Max(Mathf.Abs(lossy.y), Mathf.Abs(lossy.z));
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else if (dir == 1) scaleR = Mathf.Max(Mathf.Abs(lossy.x), Mathf.Abs(lossy.z));
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else scaleR = Mathf.Max(Mathf.Abs(lossy.x), Mathf.Abs(lossy.y));
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radius = _cap.radius * scaleR;
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Vector3 center = transform.TransformPoint(_cap.center);
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Vector3 axisWorld = (dir == 0) ? transform.right : (dir == 1) ? transform.up : transform.forward;
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float heightWorld = Mathf.Max(0f, _cap.height * scaleAlong);
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float cylinderLen = Mathf.Max(0f, heightWorld - 2f * radius);
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Vector3 half = axisWorld * (cylinderLen * 0.5f);
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a = center - half;
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b = center + half;
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}
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}
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```
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---
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## 你该怎么调（针对“两个角度来回变”）
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先用这组“稳的起步值”：
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* `samplePoints = 9`
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* `buoyancyScale = 1.4 ~ 2.2`
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* `verticalDamping = 2.0 ~ 6.0`（弹跳就加）
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* `angularDamping = 0.3 ~ 1.0`（摆动就加，但别太大）
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* 如果你是浮漂想要“自动立漂”：
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* `uprightSpring = 0.5 ~ 3.0`
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* `uprightDamping = 0.3 ~ 1.5`
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---
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## 额外一句：为什么 upright 会明显改善“两个角度抽动”
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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。
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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）。
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