279 lines
8.7 KiB
C#
279 lines
8.7 KiB
C#
using UnityEngine;
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[RequireComponent(typeof(LineRenderer))]
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public class Rope : MonoBehaviour
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{
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[Header("Demo Parameters")] [SerializeField, Min(0)]
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float mouseOffset = 10f;
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[Header("Verlet Parameters")] [SerializeField]
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float nodeDistance = 0.35f;
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[SerializeField] float nodeColliderRadius = 0.2f;
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[SerializeField] float gravityStrength = 2;
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[SerializeField] float totalLength = 10f;
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[SerializeField, Range(0, 1)] float velocityDampen = 0.95f;
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[SerializeField, Range(0, 0.99f)] float stiffness = 0.8f;
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[SerializeField, Range(1, 10)] int iterateCollisionsEvery = 1;
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[SerializeField, Range(1, 200)] int iterations = 10;
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[SerializeField] int colliderBufferSize = 1;
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[Header("Line Renderer")] [SerializeField]
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float ropeWidth = 0.1f;
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// 私有变量
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Camera cam;
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Vector3 gravity;
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Vector3 startLock;
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Vector3 endLock;
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bool isStartLocked = false;
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bool isEndLocked = false;
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// 数组和缓存
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Vector3[] currentNodePositions;
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Vector3[] previousNodePositions;
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Collider[] colliderHitBuffer;
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LineRenderer lineRenderer;
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GameObject nodeTester;
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SphereCollider nodeCollider;
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int totalNodes;
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float lastTotalLength; // 用于检测长度变化
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void Awake()
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{
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// 获取组件引用
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lineRenderer = GetComponent<LineRenderer>();
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cam = Camera.main;
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gravity = new Vector3(0, -gravityStrength, 0);
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// 初始化节点测试器
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nodeTester = new GameObject("Node Tester");
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nodeTester.layer = 8;
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nodeCollider = nodeTester.AddComponent<SphereCollider>();
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nodeCollider.radius = nodeColliderRadius;
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// 初始化长度跟踪
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lastTotalLength = totalLength;
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InitializeRope();
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}
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void InitializeRope()
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{
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// 计算节点数量
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totalNodes = Mathf.FloorToInt(totalLength / nodeDistance) + 1;
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float remainingLength = totalLength % nodeDistance;
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// 如果剩余长度大于0，增加一个节点
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if (remainingLength > 0 && totalLength > nodeDistance)
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{
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totalNodes++;
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}
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// 初始化或调整数组大小
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System.Array.Resize(ref currentNodePositions, totalNodes);
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System.Array.Resize(ref previousNodePositions, totalNodes);
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colliderHitBuffer = new Collider[colliderBufferSize];
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// 初始化节点位置
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Vector3 startPos = transform.position;
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for (int i = 0; i < totalNodes; i++)
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{
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// 如果是最后一个节点且有剩余长度，使用剩余长度
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float distance = (i == totalNodes - 1 && remainingLength > 0) ? remainingLength : nodeDistance;
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// 如果数组已有数据，保持现有位置，否则初始化新位置
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if (currentNodePositions[i] == null)
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{
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currentNodePositions[i] = startPos;
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previousNodePositions[i] = startPos;
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}
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startPos.y -= distance;
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}
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// 设置线渲染器
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lineRenderer.startWidth = ropeWidth;
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lineRenderer.endWidth = ropeWidth;
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lineRenderer.positionCount = totalNodes;
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}
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void Update()
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{
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// 检查长度是否变化
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if (!Mathf.Approximately(totalLength, lastTotalLength))
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{
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AdjustRopeLength();
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lastTotalLength = totalLength;
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}
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// 处理鼠标输入
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if (Input.GetMouseButtonDown(0))
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{
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if (!isStartLocked)
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{
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isStartLocked = true;
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startLock = GetMouseWorldPosition();
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}
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else if (!isEndLocked)
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{
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isEndLocked = true;
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endLock = GetMouseWorldPosition();
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}
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}
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else if (!isStartLocked)
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{
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startLock = GetMouseWorldPosition();
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}
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else if (isStartLocked && !isEndLocked)
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{
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endLock = GetMouseWorldPosition();
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}
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DrawRope();
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}
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void AdjustRopeLength()
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{
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// 保存旧位置
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Vector3[] oldPositions = (Vector3[])currentNodePositions.Clone();
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Vector3[] oldPrevPositions = (Vector3[])previousNodePositions.Clone();
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// 重新初始化绳索
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InitializeRope();
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// 尽可能保留旧位置数据
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int copyLength = Mathf.Min(oldPositions.Length, currentNodePositions.Length);
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System.Array.Copy(oldPositions, currentNodePositions, copyLength);
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System.Array.Copy(oldPrevPositions, previousNodePositions, copyLength);
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// 如果长度增加，初始化新增节点的位置
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if (currentNodePositions.Length > oldPositions.Length)
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{
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Vector3 lastPos = oldPositions[oldPositions.Length - 1];
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for (int i = oldPositions.Length; i < currentNodePositions.Length; i++)
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{
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float distance = (i == currentNodePositions.Length - 1 && (totalLength % nodeDistance) > 0) ?
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(totalLength % nodeDistance) : nodeDistance;
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lastPos.y -= distance;
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currentNodePositions[i] = lastPos;
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previousNodePositions[i] = lastPos;
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}
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}
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}
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void FixedUpdate()
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{
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Simulate();
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for (int i = 0; i < iterations; i++)
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{
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ApplyConstraint();
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// 减少碰撞检测频率
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if (i % (iterateCollisionsEvery + 1) == 0)
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{
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AdjustCollisions();
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}
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}
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}
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Vector3 GetMouseWorldPosition()
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{
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return cam.ScreenToWorldPoint(Input.mousePosition + new Vector3(0, 0, mouseOffset));
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}
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void Simulate()
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{
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float fixedDt = Time.fixedDeltaTime;
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for (int i = 0; i < totalNodes; i++)
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{
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// 计算并应用速度
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Vector3 velocity = (currentNodePositions[i] - previousNodePositions[i]) * velocityDampen;
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previousNodePositions[i] = currentNodePositions[i];
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currentNodePositions[i] += velocity + gravity * fixedDt;
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}
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}
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void ApplyConstraint()
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{
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// 锁定端点
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currentNodePositions[0] = startLock;
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if (isStartLocked && isEndLocked)
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{
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currentNodePositions[totalNodes - 1] = endLock;
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}
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// 预计算所有常用值
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float halfStiffness = 0.5f * stiffness;
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int nodeCountMinusOne = totalNodes - 1;
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for (int i = 0; i < nodeCountMinusOne; i++)
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{
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Vector3 node1 = currentNodePositions[i];
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Vector3 node2 = currentNodePositions[i + 1];
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Vector3 diff = node1 - node2;
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// 计算期望的距离 - 如果是最后一个段且有剩余长度，使用剩余长度
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float desiredDistance = (i == nodeCountMinusOne - 1 && (totalLength % nodeDistance) > 0) ?
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(totalLength % nodeDistance) : nodeDistance;
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float sqrDesiredDistance = desiredDistance * desiredDistance;
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float sqrDistance = diff.x * diff.x + diff.y * diff.y + diff.z * diff.z;
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// 只有当距离差异超过一定阈值时才调整
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if (Mathf.Abs(sqrDistance - sqrDesiredDistance) > 0.001f)
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{
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float distance = Mathf.Sqrt(sqrDistance);
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float difference = desiredDistance - distance;
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Vector3 direction = diff / distance;
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Vector3 adjustment = direction * (difference * halfStiffness);
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currentNodePositions[i] += adjustment;
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currentNodePositions[i + 1] -= adjustment;
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}
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}
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}
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void AdjustCollisions()
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{
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for (int i = 1; i < totalNodes; i += 2)
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{
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int hits = Physics.OverlapSphereNonAlloc(
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currentNodePositions[i],
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nodeColliderRadius,
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colliderHitBuffer,
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~(1 << 8));
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for (int n = 0; n < hits; n++)
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{
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if (Physics.ComputePenetration(
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nodeCollider,
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currentNodePositions[i],
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Quaternion.identity,
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colliderHitBuffer[n],
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colliderHitBuffer[n].transform.position,
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colliderHitBuffer[n].transform.rotation,
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out Vector3 direction,
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out float distance))
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{
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currentNodePositions[i] += direction * distance;
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}
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}
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}
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}
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void DrawRope()
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{
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lineRenderer.positionCount = totalNodes;
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lineRenderer.SetPositions(currentNodePositions);
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}
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void OnDestroy()
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{
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if (nodeTester != null)
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{
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Destroy(nodeTester);
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}
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}
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} |