基于Unity3D的循环路径的实现

废话少说，直接上代码：

路径脚本

using UnityEngine;using System.Collections;using System.Collections.Generic;#if UNITY_EDITORusing UnityEditor;#endifpublic class WaypointCircuit : MonoBehaviour {public WaypointList waypointList = new WaypointList();[SerializeField] bool smoothRoute = true;int numPoints;Vector3[] points;float[] distances;public float editorVisualisationSubsteps = 100;public float Length { get; private set; }public Transform[] Waypoints { get { return waypointList.items; } }//this being here will save GC allocsint p0n;int p1n;int p2n;int p3n;private float i;Vector3 P0;Vector3 P1;Vector3 P2;Vector3 P3;// Use this for initializationvoid Awake () {if (Waypoints.Length > 1){CachePositionsAndDistances();}numPoints = Waypoints.Length;}public RoutePoint GetRoutePoint(float dist){// position and directionVector3 p1 = GetRoutePosition(dist);Vector3 p2 = GetRoutePosition(dist + 0.1f);Vector3 delta = p2-p1;return new RoutePoint( p1, delta.normalized );}public Vector3 GetRoutePosition(float dist){int point = 0;if (Length == 0){Length = distances[distances.Length-1];}dist = Mathf.Repeat(dist,Length);while (distances[point] < dist) { ++point; }// get nearest two points, ensuring points wrap-around start & end of circuitp1n = ((point-1) + numPoints) % numPoints;p2n = point;// found point numbers, now find interpolation value between the two middle pointsi = Mathf.InverseLerp(distances[p1n],distances[p2n],dist);if (smoothRoute){// smooth catmull-rom calculation between the two relevant points// get indices for the surrounding 2 points, because// four points are required by the catmull-rom functionp0n = ((point-2) + numPoints) % numPoints;p3n = (point+1) % numPoints;// 2nd point may have been the 'last' point - a dupe of the first,// (to give a value of max track distance instead of zero)// but now it must be wrapped back to zero if that was the case.p2n = p2n % numPoints;P0 = points[ p0n ];P1 = points[ p1n ];P2 = points[ p2n ];P3 = points[ p3n ];return CatmullRom(P0,P1,P2,P3,i);} else {// simple linear lerp between the two points:p1n = ((point-1) + numPoints) % numPoints;p2n = point;return Vector3.Lerp ( points[p1n], points[p2n], i );}}Vector3 CatmullRom(Vector3 _P0, Vector3 _P1, Vector3 _P2, Vector3 _P3, float _i){// comments are no use here... it's the catmull-rom equation.// Un-magic this, lord vector!return 0.5f * ( (2 * _P1) + (-_P0 + _P2) * _i + (2*_P0 - 5*_P1 + 4*_P2 - _P3) * _i*_i + (-_P0 + 3*_P1 - 3*_P2 + _P3) * _i*_i*_i );}void CachePositionsAndDistances(){// transfer the position of each point and distances between points to arrays for// speed of lookup at runtimepoints = new Vector3[Waypoints.Length+1];distances = new float[Waypoints.Length+1];float accumulateDistance = 0;for (int i = 0; i<points.Length; ++i) {var t1 =  Waypoints[(i)% Waypoints.Length ];var t2 =  Waypoints[(i+1)% Waypoints.Length ];if (t1 != null && t2 != null){Vector3 p1 = t1.position;Vector3 p2 = t2.position;points[i] = Waypoints[i % Waypoints.Length].position;distances[i] = accumulateDistance;accumulateDistance += (p1 - p2).magnitude;} }}void OnDrawGizmos(){DrawGizmos(false);}void OnDrawGizmosSelected(){DrawGizmos(true);}void DrawGizmos(bool selected){waypointList.circuit = this;if (Waypoints.Length > 1){numPoints = Waypoints.Length;CachePositionsAndDistances();Length = distances[distances.Length-1];Gizmos.color = selected ? Color.yellow : new Color(1,1,0,0.5f);Vector3 prev = Waypoints[0].position;if (smoothRoute){for (float dist=0; dist<Length; dist += Length/editorVisualisationSubsteps){Vector3 next = GetRoutePosition(dist+1);Gizmos.DrawLine( prev, next );prev = next;}Gizmos.DrawLine( prev, Waypoints[0].position );} else {for (int n=0; n<Waypoints.Length; ++n){Vector3 next = Waypoints[(n+1) % Waypoints.Length].position;Gizmos.DrawLine( prev, next );prev = next;}}}}[System.Serializable]public class WaypointList{public WaypointCircuit circuit;public Transform[] items = new Transform[0];}public struct RoutePoint{public Vector3 position;public Vector3 direction;public RoutePoint(Vector3 position, Vector3 direction){this.position = position;this.direction = direction;}}}#if UNITY_EDITOR[CustomPropertyDrawer (typeof(WaypointCircuit.WaypointList))]public class WaypointListDrawer : PropertyDrawer{float lineHeight = 18;float spacing = 4;public override void OnGUI (Rect position, SerializedProperty property, GUIContent label){EditorGUI.BeginProperty (position, label, property);float x = position.x;float y = position.y;float inspectorWidth = position.width;// Draw label// Don't make child fields be indentedvar indent = EditorGUI.indentLevel;EditorGUI.indentLevel = 0;var items = property.FindPropertyRelative ("items");string[] titles = new string[] { "Transform", "", "", "" };string[] props = new string[] { "transform", "^", "v", "-" };float[] widths = new float[] { .7f, .1f, .1f, .1f };float lineHeight = 18;bool changedLength = false;if (items.arraySize > 0){for (int i=-1; i<items.arraySize; ++i) {var item = items.GetArrayElementAtIndex (i);float rowX = x;for (int n=0; n<props.Length; ++n){float w = widths[n] * inspectorWidth;// Calculate rectsRect rect = new Rect (rowX, y, w, lineHeight);rowX += w;if (i == -1){EditorGUI.LabelField(rect, titles[n]);} else {if (n==0){EditorGUI.ObjectField(rect, item.objectReferenceValue, typeof(Transform), true);                        } else {if (GUI.Button (rect, props[n])){switch (props[n]){case "-":items.DeleteArrayElementAtIndex(i);items.DeleteArrayElementAtIndex(i);changedLength = true;break;case "v":if (i > 0) items.MoveArrayElement(i,i+1);break;case "^":if (i < items.arraySize-1) items.MoveArrayElement(i,i-1);break;}}}}}y += lineHeight + spacing;if (changedLength){break;}}} else {// add buttonvar addButtonRect = new Rect ((x + position.width) - widths[widths.Length-1]*inspectorWidth, y, widths[widths.Length-1]*inspectorWidth, lineHeight);if (GUI.Button (addButtonRect, "+")) {items.InsertArrayElementAtIndex(items.arraySize);}y += lineHeight + spacing;}// add all buttonvar addAllButtonRect = new Rect (x, y, inspectorWidth, lineHeight);if (GUI.Button (addAllButtonRect, "Assign using all child objects")){var circuit = property.FindPropertyRelative("circuit").objectReferenceValue as WaypointCircuit;var children = new Transform[ circuit.transform.childCount ];int n=0; foreach (Transform child in circuit.transform) children[n++] = child;System.Array.Sort( children, new TransformNameComparer() );circuit.waypointList.items = new Transform[children.Length];for (n=0; n<children.Length; ++n){circuit.waypointList.items[n] = children[n];}}y += lineHeight + spacing;// rename all buttonvar renameButtonRect = new Rect (x, y, inspectorWidth, lineHeight);if (GUI.Button (renameButtonRect, "Auto Rename numerically from this order")) {var circuit = property.FindPropertyRelative("circuit").objectReferenceValue as WaypointCircuit;int n=0; foreach (Transform child in circuit.waypointList.items) child.name = "Waypoint "+(n++).ToString("000");}y += lineHeight + spacing;// Set indent back to what it wasEditorGUI.indentLevel = indent;EditorGUI.EndProperty ();}public override float GetPropertyHeight (SerializedProperty property, GUIContent label){SerializedProperty items = property.FindPropertyRelative ("items");float lineAndSpace = lineHeight + spacing;return 40 + (items.arraySize * lineAndSpace) + lineAndSpace;}// comparer for check distances in ray cast hitspublic class TransformNameComparer: IComparer{public int Compare(object x, object y) {return ((Transform)x).name.CompareTo(((Transform)y).name);}   }}#endif

角色脚本

using UnityEngine;using System.Collections;public class Follow : MonoBehaviour {// 路径脚本[SerializeField]private WaypointCircuit circuit;//移动距离private float dis;//移动速度private float speed;// Use this for initializationvoid Start(){dis = 0;speed = 10;}// Update is called once per framevoid Update(){//计算距离dis += Time.deltaTime * speed;//获取相应距离在路径上的位置坐标transform.position = circuit.GetRoutePoint (dis).position;//获取相应距离在路径上的方向transform.rotation = Quaternion.LookRotation (circuit.GetRoutePoint (dis).direction);}}