浮漂逻辑

Assets/Scripts/Test/CapsuleBuoyancy.cs

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+using UnityEngine;
+
+[RequireComponent(typeof(Rigidbody))]
+[RequireComponent(typeof(CapsuleCollider))]
+public class CapsuleBuoyancy : MonoBehaviour
+{
+    [Header("Water Settings")]
+    public float waterHeight = 0f;          // 水面高度
+    public float waterDensity = 1000f;      // 水密度
+
+    [Header("Buoyancy Settings")]
+    public int samplePoints = 8;            // 采样点数量
+    public float buoyancyMultiplier = 1.0f; // 浮力强度调节
+    public float waterDrag = 1.5f;          // 水阻力
+    public float waterAngularDrag = 1.5f;   // 水角阻力
+
+    private Rigidbody rb;
+    private CapsuleCollider capsule;
+
+    private float capsuleVolume;
+    private float gravity;
+
+    void Start()
+    {
+        rb = GetComponent<Rigidbody>();
+        capsule = GetComponent<CapsuleCollider>();
+
+        gravity = Physics.gravity.magnitude;
+
+        CalculateCapsuleVolume();
+    }
+
+    void FixedUpdate()
+    {
+        ApplyBuoyancy();
+    }
+
+    void CalculateCapsuleVolume()
+    {
+        float radius = capsule.radius * Mathf.Max(transform.localScale.x, transform.localScale.z);
+        float height = Mathf.Max(0, capsule.height * transform.localScale.y - 2f * radius);
+
+        float cylinderVolume = Mathf.PI * radius * radius * height;
+        float sphereVolume = (4f / 3f) * Mathf.PI * radius * radius * radius;
+
+        capsuleVolume = cylinderVolume + sphereVolume;
+    }
+
+    void ApplyBuoyancy()
+    {
+        float submergedRatioTotal = 0f;
+
+        for (int i = 0; i < samplePoints; i++)
+        {
+            float t = (float)i / (samplePoints - 1);
+            Vector3 localPoint = Vector3.up * Mathf.Lerp(
+                -capsule.height * 0.5f + capsule.radius,
+                capsule.height * 0.5f - capsule.radius,
+                t);
+
+            Vector3 worldPoint = transform.TransformPoint(localPoint);
+
+            float depth = waterHeight - worldPoint.y;
+
+            if (depth > 0f)
+            {
+                float normalizedDepth = Mathf.Clamp01(depth / (capsule.height / samplePoints));
+                submergedRatioTotal += normalizedDepth;
+
+                float forceMagnitude =
+                    waterDensity *
+                    gravity *
+                    (capsuleVolume / samplePoints) *
+                    normalizedDepth *
+                    buoyancyMultiplier;
+
+                Vector3 buoyancyForce = Vector3.up * forceMagnitude;
+
+                rb.AddForceAtPosition(buoyancyForce, worldPoint, ForceMode.Force);
+            }
+        }
+
+        // 如果在水中，加阻力
+        if (submergedRatioTotal > 0f)
+        {
+            rb.linearDamping = waterDrag;
+            rb.angularDamping = waterAngularDrag;
+        }
+        else
+        {
+            rb.linearDamping = 0f;
+            rb.angularDamping = 0.05f;
+        }
+    }
+}