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_EDITORusing 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 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：