using System.Collections;
using System.Collections.Generic;
using UnityEngine;public static class Bezier
{/// <summary>/// 获取曲线上某点的坐标/// </summary>/// <param name="p0"> 曲线起点 </param>/// <param name="p1"> 曲线终点 </param>/// <param name="p2"> 曲线调整点1 </param>/// <param name="p3"> 曲线调整点2 </param>/// <param name="t"> 曲线插值t </param>/// <returns></returns>public static Vector3 GetPoint(Vector3 p0, Vector3 p1, Vector3 p2, Vector3 p3, float t){t = Mathf.Clamp01(t);float oneMinusT = 1f - t;return oneMinusT * oneMinusT * oneMinusT * p0 +3f * oneMinusT * oneMinusT * t * p1 +3f * oneMinusT * t * t * p2 +t * t * t * p3;}/// <summary>/// 获取曲线某点的切线/// </summary>/// <param name="p0"> 曲线起点 </param>/// <param name="p1"> 曲线终点 </param>/// <param name="p2"> 曲线调整点1 </param>/// <param name="p3"> 曲线调整点2 </param>/// <param name="t"> 曲线插值t </param>/// <returns></returns>public static Vector3 GetFirstDerivative(Vector3 p0, Vector3 p1, Vector3 p2, Vector3 p3, float t){t = Mathf.Clamp01(t);float oneMinusT = 1f - t;return3f * oneMinusT * oneMinusT * (p1 - p0) +6f * oneMinusT * t * (p2 - p1) +3f * t * t * (p3 - p2);}
}

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;public enum BezierControlPointMode
{Free,Aligned,Mirrored
}public class BezierSpline : MonoBehaviour
{[SerializeField]public Vector3[] points;[SerializeField]private BezierControlPointMode[] modes;[SerializeField]private bool loop;public bool Loop{get { return loop; }set{loop = value;if (value == true){modes[modes.Length - 1] = modes[0];SetControlPoint(0, points[0]);}}}/// <summary>/// 控制点总数/// </summary>/// <value></value>public int ControlPointCount{get { return points.Length; }}/// <summary>/// 获取控制点坐标/// </summary>/// <param name="index"></param>/// <returns></returns>public Vector3 GetControlPoint(int index){return points[index];}/// <summary>/// 设置控制点坐标/// </summary>/// <param name="index"></param>/// <param name="point"></param>public void SetControlPoint(int index, Vector3 point){if (index % 3 == 0){//获取当前控制点变换增量Vector3 delta = point - points[index];if (loop)//保持环状{//保证所选择的曲线控制点的前后增量一致if (index == 0){points[1] += delta;points[points.Length - 2] += delta;points[points.Length - 1] = point;}else if (index == points.Length - 1){points[0] = point;points[1] += delta;points[index - 1] += delta;}else{points[index - 1] += delta;points[index + 1] += delta;}}else{//适配以交点对称的两个点或一个点的增量if (index > 0){points[index - 1] += delta;}if (index + 1 < points.Length){points[index + 1] += delta;}}points[index] = point;EnforceMode(index);}}public void Reset(){points = new Vector3[]{new Vector3(1f,0f,0f),new Vector3(2f,0f,0f),new Vector3(3f,0f,0f),new Vector3(4f,0f,0f)};modes = new BezierControlPointMode[]{BezierControlPointMode.Free,BezierControlPointMode.Free};}/// <summary>/// 获取当前控制点的控制模式/// </summary>/// <param name="index"></param>/// <returns></returns>public BezierControlPointMode GetControlPointMode(int index){return modes[(index + 1) / 3];}/// <summary>/// 设置当前点的控制模式/// </summary>/// <param name="index"></param>/// <param name="mode"></param>public void SetControlPonitMode(int index, BezierControlPointMode mode){int modeIndex = (index + 1) / 3;modes[modeIndex] = mode;if (loop){//收尾相连if (modeIndex == 0){modes[modes.Length - 1] = mode;}else if (modeIndex == modes.Length - 1){modes[0] = mode;}}EnforceMode(index);}/// <summary>/// 强制修改模式/// </summary>/// <param name="index"></param>private void EnforceMode(int index){int modeIndex = (index + 1) / 3;//确定曲线索引BezierControlPointMode mode = modes[modeIndex];//曲线端点两个点和曲线终点两个点舍弃if (mode == BezierControlPointMode.Free || !loop && (modeIndex == 0 || modeIndex == modes.Length - 1))return;//获取曲线相交的中点int middleIndex = modeIndex * 3;int fixedIndex, enforcedIndex;//修正右侧点if (index <= middleIndex){fixedIndex = middleIndex - 1;if (fixedIndex < 0){fixedIndex = points.Length - 2;}enforcedIndex = middleIndex + 1;if (enforcedIndex >= points.Length){enforcedIndex = 1;}}else{//修正左侧点fixedIndex = middleIndex + 1;if (fixedIndex >= points.Length){fixedIndex = 1;}enforcedIndex = middleIndex - 1;if (enforcedIndex < 0){enforcedIndex = points.Length - 2;}}//将与中心对称的另一个点修正与选择的点Vector3 middle = points[middleIndex];//以中心点对称Vector3 enforcedTangent = middle - points[fixedIndex];if (mode == BezierControlPointMode.Aligned){//以中心点排齐enforcedTangent = enforcedTangent.normalized * Vector3.Distance(middle, points[enforcedIndex]);}//修正points[enforcedIndex] = middle + enforcedTangent;}/// <summary>/// 曲线总数/// </summary>/// <value></value>public int CurveCount{get { return (points.Length - 1) / 3; }}/// <summary>/// 根据插值t获取曲线上对应点坐标/// </summary>/// <param name="t"></param>/// <returns></returns>public Vector3 GetPoint(float t){int i;if (t >= 1f){t = 1f;i = points.Length - 4;//取最后一段曲线}else{//找到当前所属曲线对应的tt = Mathf.Clamp01(t) * CurveCount;i = (int)t;t -= i;i *= 3;}return transform.TransformPoint(Bezier.GetPoint(points[i], points[i + 1], points[i + 2], points[i + 3], t));}/// <summary>/// 根据插值t获取曲线上对应点方向/// </summary>/// <param name="t"></param>/// <returns></returns>public Vector3 GetVelocity(float t){int i;if (t >= 1f){t = 1f;i = points.Length - 4;//取最后一段曲线}else{//找到当前所属曲线对应的tt = Mathf.Clamp01(t) * CurveCount;i = (int)t;t -= i;i *= 3;}//速度矢量return transform.TransformPoint(Bezier.GetFirstDerivative(points[i], points[i + 1], points[i + 2], points[i + 3], t) - transform.position);}/// <summary>/// 根据插值t获取曲线上对应点方向的归一化坐标/// </summary>/// <param name="t"></param>/// <returns></returns>public Vector3 GetDirection(float t){return GetVelocity(t).normalized;}/// <summary>/// 添加一段曲线(起点，终点，2个控制点)/// </summary>public void AddCurve(){//曲线控制点Vector3 point = points[points.Length - 1];Array.Resize(ref points, points.Length + 3);point.x += 1f;points[points.Length - 3] = point;point.x += 1f;points[points.Length - 2] = point;point.x += 1f;points[points.Length - 1] = point;//曲线调整模式Array.Resize(ref modes, modes.Length + 1);modes[modes.Length - 1] = modes[modes.Length - 2];EnforceMode(points.Length - 4);//曲线呈环状if (loop){points[points.Length - 1] = points[0];modes[modes.Length - 1] = modes[0];EnforceMode(0);}}
}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
using System;[CustomEditor(typeof(BezierSpline))]
public class BezierSplineInspector : Editor
{//样条曲线private BezierSpline spline;//拖动对象变换private Transform handleTransform;//拖动对象旋转private Quaternion handleRotation;//private const int stepsPerCurve = 10;private float directionScale = 0.5f;private const float handleSize = 0.04f;private const float pickSize = 0.06f;private int selectedIndex = -1;public override void OnInspectorGUI(){spline = target as BezierSpline;//添加loop按钮EditorGUI.BeginChangeCheck();bool loop = EditorGUILayout.Toggle("Loop", spline.Loop);if (EditorGUI.EndChangeCheck()){Undo.RecordObject(spline, "Toggle Loop");EditorUtility.SetDirty(spline);spline.Loop = loop;}if (selectedIndex >= 0 && selectedIndex < spline.ControlPointCount)DrawSelectedPointInspector();//添加曲线按钮    if (GUILayout.Button("Add Curve")){Undo.RecordObject(spline, "Add Curve");spline.AddCurve();EditorUtility.SetDirty(spline);}}private void DrawSelectedPointInspector(){GUILayout.Label("Selected Point");//位移坐标显示EditorGUI.BeginChangeCheck();Vector3 point = EditorGUILayout.Vector3Field("Position", spline.GetControlPoint(selectedIndex));if (EditorGUI.EndChangeCheck()){Undo.RecordObject(spline, "Move Ponit");EditorUtility.SetDirty(spline);spline.SetControlPoint(selectedIndex, point);}//mode枚举EditorGUI.BeginChangeCheck();BezierControlPointMode mode = (BezierControlPointMode)EditorGUILayout.EnumPopup("Mode", spline.GetControlPointMode(selectedIndex));if (EditorGUI.EndChangeCheck()){Undo.RecordObject(spline, "Change Point Mode");spline.SetControlPonitMode(selectedIndex, mode);EditorUtility.SetDirty(spline);}}/// <summary>/// 场景UI/// </summary>private void OnSceneGUI(){spline = target as BezierSpline;handleTransform = spline.transform;handleRotation = Tools.pivotRotation == PivotRotation.Local ? handleTransform.rotation : Quaternion.identity;//曲线起点Vector3 p0 = ShowPoint(0);for (int i = 1; i < spline.ControlPointCount; i += 3){//曲线调整点1Vector3 p1 = ShowPoint(i);//曲线调整点2Vector3 p2 = ShowPoint(i + 1);//曲线终点Vector3 p3 = ShowPoint(i + 2);Handles.color = Color.gray;//控制点之间用直线表示Handles.DrawLine(p0, p1);Handles.DrawLine(p2, p3);//贝塞尔曲线API接口Handles.DrawBezier(p0, p3, p1, p2, Color.white, null, 2f);p0 = p3;//实际贝塞尔曲线显示算法// int lineStep = 50;//决定曲线平滑度// for (int bezierPonitCount = 0; bezierPonitCount < lineStep; bezierPonitCount++)// {//     Handles.color = Color.white;//     //曲线上的某个点//     Vector3 p = spline.GetPoint(bezierPonitCount / (float)lineStep);//     Handles.DrawLine(p0, p);//     //线段的终点作为下一个点的起点//     p0 = p;// }}ShowDirections();}/// <summary>/// 显示曲线某个点的方向/// </summary>private void ShowDirections(){Handles.color = Color.green;Vector3 point = spline.GetPoint(0f);Handles.DrawLine(point, point + spline.GetDirection(0f) * directionScale);//每段曲线显示10个点方向int steps = stepsPerCurve * spline.CurveCount;for (int i = 0; i < steps; i++){point = spline.GetPoint(i / (float)steps);Handles.DrawLine(point, point + spline.GetDirection(i / (float)steps) * directionScale);}}private static Color[] modeColors ={Color.white,Color.yellow,Color.cyan};/// <summary>/// 展示曲线控制点/// </summary>/// <param name="index"></param>/// <returns></returns>private Vector3 ShowPoint(int index){Vector3 point = handleTransform.TransformPoint(spline.GetControlPoint(index));//根据点获取世界空间显示的尺寸float size = HandleUtility.GetHandleSize(point);if (index == 0)size *= 2f;Handles.color = modeColors[(int)spline.GetControlPointMode(index)];if (Handles.Button(point, handleRotation, size * handleSize, size * pickSize, Handles.DotCap)){selectedIndex = index;Repaint();}if (selectedIndex == index){EditorGUI.BeginChangeCheck();//获取当前控制点的坐标point = Handles.DoPositionHandle(point, handleRotation);if (EditorGUI.EndChangeCheck()){Undo.RecordObject(spline, "Move Ponit");EditorUtility.SetDirty(spline);spline.SetControlPoint(index, handleTransform.InverseTransformPoint(point));}}return point;}
}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;public enum SplineWalkerMode
{Once,Loop,PingPong
}public class SplineWalker : MonoBehaviour
{public SplineWalkerMode mode;public BezierSpline spline;public float duration = 1f;private float progress = 0;private bool gongForward = true;public bool lookForward;void Update(){if (gongForward){progress += Time.deltaTime / duration;if (progress > 1f){if (mode == SplineWalkerMode.Once){progress = 1f;}else if (mode == SplineWalkerMode.Loop){progress -= 1f;}else{progress = 2f - progress;gongForward = false;}}}else{progress -= Time.deltaTime / duration;if (progress < 0f){progress = -progress;gongForward = true;}}Vector3 position = spline.GetPoint(progress);transform.localPosition = position;if (lookForward)transform.LookAt(position + spline.GetDirection(progress));}
}