130 lines
4.2 KiB
C#
130 lines
4.2 KiB
C#
using UnityEngine;
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[DisallowMultipleComponent]
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[RequireComponent(typeof(Rigidbody))]
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[RequireComponent(typeof(CapsuleCollider))]
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public class BobberBuoyancyStable : MonoBehaviour
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{
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[Header("Water")]
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public float waterLevelY = 0f;
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[Tooltip("必须至少浸入这么深才开始产生浮力（防止还没入水就被顶）")]
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public float enterWaterDepth = 0.003f; // 3mm（按你的尺度改）
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[Tooltip("在这个深度范围内做平滑过渡（越大越软）")]
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public float smoothDepth = 0.02f;
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[Header("Buoyancy Spring")]
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public float buoyancySpring = 30f;
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public float buoyancyDamping = 8f;
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[Tooltip("最大上浮加速度限制(0=不限制)")]
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public float maxUpAcceleration = 0f;
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[Header("Water Drag")]
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public float extraLinearDampingInWater = 2f;
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public float extraAngularDampingInWater = 2f;
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[Header("Center Of Mass")]
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public bool driveCenterOfMassFromCapsule = true;
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public Vector3 extraCenterOfMassOffset = new Vector3(0f, -0.01f, 0f);
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[Header("Righting")]
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public float rightingTorque = 1.5f;
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public float rightingDamping = 0.5f;
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Rigidbody rb;
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CapsuleCollider cap;
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float airLinearDamping;
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float airAngularDamping;
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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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rb.useGravity = true;
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airLinearDamping = rb.linearDamping;
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airAngularDamping = rb.angularDamping;
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ApplyCenterOfMass();
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rb.maxAngularVelocity = 50f;
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}
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void FixedUpdate()
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{
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ApplyCenterOfMass();
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Bounds b = cap.bounds;
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float bottomY = b.min.y;
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float topY = b.max.y;
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// 用“底部点”判定是否真正入水（必须超过阈值）
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float bottomSubmersion = waterLevelY - bottomY; // >0 表示底部在水下
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if (bottomSubmersion <= enterWaterDepth)
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{
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// 认为未入水：不施加浮力，恢复空气阻尼
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rb.linearDamping = airLinearDamping;
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rb.angularDamping = airAngularDamping;
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return;
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}
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// 进入水中：阻尼随浸入增强
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// 这里用一个0~1的平滑权重，避免刚入水就“猛顶”
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float w = Smooth01((bottomSubmersion - enterWaterDepth) / Mathf.Max(1e-4f, smoothDepth));
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rb.linearDamping = airLinearDamping + extraLinearDampingInWater * w;
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rb.angularDamping = airAngularDamping + extraAngularDampingInWater * w;
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// 垂直速度（用刚体自身速度就够稳定）
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float vY = rb.linearVelocity.y;
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// 弹簧+阻尼浮力（仅向上）
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float forceY = buoyancySpring * bottomSubmersion - buoyancyDamping * vY;
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if (forceY < 0f) forceY = 0f;
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// 平滑权重：刚入水时逐渐接管
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forceY *= w;
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// 限制最大上浮加速度（可选）
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if (maxUpAcceleration > 0f)
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{
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float maxForce = rb.mass * maxUpAcceleration;
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if (forceY > maxForce) forceY = maxForce;
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}
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// 浮力作用点：必须放在水面下（否则会出现奇怪力矩）
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float buoyY = Mathf.Min(waterLevelY - 0.001f, topY); // 强制在水面下1mm
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buoyY = Mathf.Max(buoyY, bottomY); // 不低于底部
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Vector3 buoyPoint = new Vector3(b.center.x, buoyY, b.center.z);
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rb.AddForceAtPosition(Vector3.up * forceY, buoyPoint, ForceMode.Force);
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// 归正扭矩（只在水里生效）
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Vector3 up = transform.up;
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Vector3 axis = Vector3.Cross(up, Vector3.up);
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float mag = axis.magnitude;
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if (mag > 1e-4f)
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{
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axis /= mag;
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float angle = Mathf.Asin(Mathf.Clamp(mag, -1f, 1f));
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float angVelOnAxis = Vector3.Dot(rb.angularVelocity, axis);
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float torque = (rightingTorque * angle - rightingDamping * angVelOnAxis) * w;
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rb.AddTorque(axis * torque, ForceMode.Acceleration);
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}
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}
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void ApplyCenterOfMass()
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{
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if (!driveCenterOfMassFromCapsule) return;
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rb.centerOfMass = cap.center + extraCenterOfMassOffset;
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}
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static float Smooth01(float t)
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{
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t = Mathf.Clamp01(t);
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// smoothstep
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return t * t * (3f - 2f * t);
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}
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} |