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】

using System; using System.Collections; using UnityEngine; #if UNITY_EDITOR using UnityEditor; #endif namespace 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 initialization private 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 rects Rect 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：