unity的自动寻路之 ------ wayPoint寻路的实现方式

孙广东 2015.6.28

看了看 Unity的官方案例，就顺便看了 wayPoint相关。

效果：

WaypointProgressTracker.cs 【固定】

WaypointCircuit.cs 【固定】

using System;
using System.Collections;
using UnityEngine;
#if UNITY_EDITOR
using UnityEditor;#endifnamespace UnityStandardAssets.Utility
{public class WaypointCircuit : MonoBehaviour{public WaypointList waypointList = new WaypointList();[SerializeField] private bool smoothRoute = true;private int numPoints;private Vector3[] points;private float[] distances;public float editorVisualisationSubsteps = 100;public float Length { get; private set; }public Transform[] Waypoints{get { return waypointList.items; }}// 这是在这里会保存 GC 分配private int p0n;private int p1n;private int p2n;private int p3n;private float i;private Vector3 P0;private Vector3 P1;private Vector3 P2;private Vector3 P3;// Use this for initializationprivate void Awake(){if (Waypoints.Length > 1){CachePositionsAndDistances();}numPoints = Waypoints.Length;}public RoutePoint GetRoutePoint(float dist){// 位置和方向Vector3 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 circuit// 得到最近的两个点，确保点环绕电路的开始与结束p1n = ((point - 1) + numPoints)%numPoints;p2n = point;// found point numbers, now find interpolation value between the two middle points// 发现点的数目，现在找到中间两点之间内的一个插值i = Mathf.InverseLerp(distances[p1n], distances[p2n], dist);if (smoothRoute){// 有关两点之间的光滑catmull-rom计算。// 获取周围的 2 点的指数，因为catmull-rom 函数要求四个点p0n = ((point - 2) + numPoints)%numPoints;p3n = (point + 1)%numPoints;// 第二个点可能已经是最后的 'last' 点了 - 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{// 两个点之间的简单线性插值:p1n = ((point - 1) + numPoints)%numPoints;p2n = point;return Vector3.Lerp(points[p1n], points[p2n], i);}}private Vector3 CatmullRom(Vector3 p0, Vector3 p1, Vector3 p2, Vector3 p3, float i){// 这是 catmull-rom 方程// 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);}private void CachePositionsAndDistances(){// transfer the position of each point and distances between points to arrays for// speed of lookup at runtime// 在运行时查找到阵列速度点之间传输的每个点和距离的位置points = 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;}}}private void OnDrawGizmos(){DrawGizmos(false);}private void OnDrawGizmosSelected(){DrawGizmos(true);}private 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;}}}}[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;}}}
}/// 编辑器对 Inspector面板的定制
namespace UnityStandardAssets.Utility.Inspector
{
#if UNITY_EDITOR[CustomPropertyDrawer(typeof (WaypointCircuit.WaypointList))]public class WaypointListDrawer : PropertyDrawer{private float lineHeight = 18;private 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;// 绘制 label// 不要缩进的子字段var indent = EditorGUI.indentLevel;EditorGUI.indentLevel = 0;var items = property.FindPropertyRelative("items");var titles = new string[] {"Transform", "", "", ""};var props = new string[] {"transform", "^", "v", "-"};var 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 rects// 计算 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 button// 添加"+"按钮var 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 button// 添加所有按钮var 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;}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 button// 重命名所有按钮var 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 was// 设置缩进EditorGUI.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 hits// 比较器检查射线发射命中的距离public class TransformNameComparer : IComparer{public int Compare(object x, object y){return ((Transform) x).name.CompareTo(((Transform) y).name);}}}
#endif
}

using System;
using UnityEngine;namespace UnityStandardAssets.Utility
{public class WaypointProgressTracker : MonoBehaviour{// 此脚本可以用于任何对象，支持沿着一条路线为标志的waypoints。// 此脚本管理向前看沿路线的数量，并跟踪进度和圈数。[SerializeField] private WaypointCircuit circuit; // 一个引用关于 waypoint-based 我们应该沿着的路线[SerializeField] private float lookAheadForTargetOffset = 5;// 我们将目标，沿着路线的偏移[SerializeField] private float lookAheadForTargetFactor = .1f;// 一个倍数，增加目标与沿着线路的距离，基于当前速度[SerializeField] private float lookAheadForSpeedOffset = 10;// 前面的偏移的唯一路线速度调整(作为waypoint目标的rotation变换)[SerializeField] private float lookAheadForSpeedFactor = .2f;// 一个倍数，沿着路线调整速度添加距离[SerializeField] private ProgressStyle progressStyle = ProgressStyle.SmoothAlongRoute;// 进度样式：是否smoothly更新位置沿着路线(好的曲线路径)或只是正常到达每个航点。[SerializeField] private float pointToPointThreshold = 4;// 接近waypoint的阈值，一旦达到这个值，目标将切换到下一个目标地点：只用于PointToPoint模式。public enum ProgressStyle{SmoothAlongRoute,PointToPoint,}// 这些是public，由其他对象读取。让一个AI知道在哪里头！public WaypointCircuit.RoutePoint targetPoint { get; private set; }public WaypointCircuit.RoutePoint speedPoint { get; private set; }public WaypointCircuit.RoutePoint progressPoint { get; private set; }public Transform target;private float progressDistance; // 圆形（环形）路线的进展，平滑smooth模式中使用。private int progressNum; // 当前waypoint数，点对点point-to-point模式中使用。private Vector3 lastPosition; // 用于计算当前速度(因为我们可能没有一个刚体组件)private float speed; // 此对象的当前速度(从最后一帧的delta计算) // 设置脚本属性private void Start(){
// 我们使用transform表示目标点，这个点被认为是为即将到来的变化的速度点。这允许此信息传递给 AI 而无需进一步依赖此组件。您可以手动创建transform设置该组件 *and* AI，然后此组件将更新它，和 AI 可以阅读它。if (target == null){target = new GameObject(name + " Waypoint Target").transform;}Reset();}// 对象重置为合理的值public void Reset(){progressDistance = 0;progressNum = 0;if (progressStyle == ProgressStyle.PointToPoint){target.position = circuit.Waypoints[progressNum].position;target.rotation = circuit.Waypoints[progressNum].rotation;}}private void Update(){if (progressStyle == ProgressStyle.SmoothAlongRoute){// 确定我们目前目标的位置 (这是不同于当前的进展位置，它是一个确定值沿着前方路线的) 我们使用 lerp 作为一种随着时间的推移速度进行平滑处理的简单方式。if (Time.deltaTime > 0){speed = Mathf.Lerp(speed, (lastPosition - transform.position).magnitude/Time.deltaTime,Time.deltaTime);}target.position =circuit.GetRoutePoint(progressDistance + lookAheadForTargetOffset + lookAheadForTargetFactor*speed).position;target.rotation =Quaternion.LookRotation(circuit.GetRoutePoint(progressDistance + lookAheadForSpeedOffset + lookAheadForSpeedFactor*speed).direction);// 得到我们的当前路线的进展progressPoint = circuit.GetRoutePoint(progressDistance);Vector3 progressDelta = progressPoint.position - transform.position;if (Vector3.Dot(progressDelta, progressPoint.direction) < 0){progressDistance += progressDelta.magnitude*0.5f;}lastPosition = transform.position;}else{// 点对点模式。 如果我们足够近，只是增加Waypoint：Vector3 targetDelta = target.position - transform.position;if (targetDelta.magnitude < pointToPointThreshold){progressNum = (progressNum + 1)%circuit.Waypoints.Length;}target.position = circuit.Waypoints[progressNum].position;target.rotation = circuit.Waypoints[progressNum].rotation;// 得到我们的当前路线的进展progressPoint = circuit.GetRoutePoint(progressDistance);Vector3 progressDelta = progressPoint.position - transform.position;if (Vector3.Dot(progressDelta, progressPoint.direction) < 0){progressDistance += progressDelta.magnitude;}lastPosition = transform.position;}}private void OnDrawGizmos(){if (Application.isPlaying){Gizmos.color = Color.green;Gizmos.DrawLine(transform.position, target.position);Gizmos.DrawWireSphere(circuit.GetRoutePosition(progressDistance), 1);Gizmos.color = Color.yellow;Gizmos.DrawLine(target.position, target.position + target.forward);}}}
}

最后： 看看Unity5的 sample中的 Car 和飞机的AI案例中：