群组行为指的是多个对象组队同时进行的情况。每个boid需满足分离，队列，凝聚三个基本的规则。
分离：群组中的每个个体都与相邻的个体保持一定的距离。
队列：群组以相同的速度，向相同的方向移动。
凝聚：与群组的中心保持最小距离。
参见：http://www.red3d.com/cwr/boids/
结构：
控制器：即头鸟下有controller类来控制自身的移动。
个体成员：单独的个体，通过引用控制器的位置信息来产生群组跟随的效果。
群组中的个体：
1 using UnityEngine;
2 using System.Collections;
3
4
5 /// <summary>
6 /// 该类是对群体中的每个个体行为的约束，即单个的鸟
7 /// </summary>
8 public class UnityFlock : MonoBehaviour
9 {
10
11 //最小速度，转向速度，随机频率，随机力
12 public float minSpeed = 20.0f;
13 public float turnSpeed = 20.0f;
14 public float randomFreq = 20.0f;
15 public float randomForce = 20.0f;
16
17 //队列属性 ：向心力，向心区间，吸引力
18 public float toOriginForce = 50.0f;
19 public float toOriginRange = 100.0f;
20
21 public float gravity = 2.0f;
22
23 //分离属性：规避力，规避半径
24 public float avoidanceForce = 20.0f;
25 public float avoidanceRadius = 50.0f;
26
27 //凝聚属性：追随速度，追随半径（相对于领导者即头鸟）
28 public float followVelocity = 4.0f;
29 public float followRadius = 40.0f;
30
31
32 //控制单个个体运动的属性：父对象即头鸟，速度，归一化速度，随机推力，父对象的推力。。。
33 private Transform origin;
34 private Vector3 velocity;
35 private Vector3 normalizedVelicity;
36 private Vector3 randomPush;
37 private Vector3 originPush;
38 private Transform[] objects;
39 private UnityFlock[] otherFlocks;//其他个体集合
40 private Transform transformCompont;
41
42
43
44 // Use this for initialization
45 void Start ()
46 {
47 randomFreq = 1.0f/randomFreq;//获取随机变化的频率
48 //设置父节点为origin
49 origin = transform.parent;
50
51 transformCompont = transform;
52
53 //临时组件数组
54 Component[] tempFlocks = null;
55
56 if (transform.parent)
57 {
58 tempFlocks = transform.parent.GetComponentsInChildren<UnityFlock>();
59 }
60
61 objects=new Transform[tempFlocks.Length];
62 otherFlocks=new UnityFlock[tempFlocks.Length];
63
64 //将群体的位置信息和群体加载到数组
65 for (int i = 0; i < tempFlocks.Length; i++)
66 {
67 objects[i] = tempFlocks[i].transform;
68 otherFlocks[i] = (UnityFlock)tempFlocks[i];
69 }
70
71 transform.parent = null;
72
73 StartCoroutine(UpdateRandom());
74 }
75
76 //基于randomFreq的频率来更新randompush的频率
77 IEnumerator UpdateRandom()
78 {
79 while (true)
80 {
81 randomPush = Random.insideUnitSphere*randomForce;//Random.insideUnitSphere随机返回单位球体类一点坐标，配合随机力度来跟新randomPush
82 yield return new WaitForSeconds(randomFreq+Random.Range(-randomFreq/2,randomFreq/2));//依据随机频率在一定时间分为类变换randomPush
83 }
84 }
85
86 // Update is called once per frame
87 void Update ()
88 {
89 float speed = velocity.magnitude;
90 Vector3 avgVelocity = Vector3.zero;
91 Vector3 avgPosition = Vector3.zero;
92 float count = 0;
93 float f = 0.0f;
94 float d = 0.0f;
95 Vector3 myPosition = transformCompont.position;
96 Vector3 forceV;
97 Vector3 toAvg;
98 Vector3 wantedVel;
99
100 for (int i = 0; i < objects.Length; i++)
101 {
102 Transform transform = objects[i];
103 if (transform != transformCompont)
104 {
105 Vector3 otherPositon = transform.position;
106
107 //平均位置来计算聚合
108 avgPosition += otherPositon;
109 count++;
110
111 //从其他群体到这个的向量
112 forceV = myPosition - otherPositon;
113
114 //上面向量的长度
115 d = forceV.magnitude;
116
117 //如果向量长度比规避半径小的话，则加大推力
118 if (d < followRadius)
119 {
120 //如果当前的向量长度小于规定的逃离半径的话，则基于 逃离半径计算对象的速度
121 if (d > 0)
122 {
123 f = 1.0f - (d/avoidanceRadius);
124 avgVelocity += (forceV / d) * f * avoidanceForce;
125 //向量除以它的模得到自己的单位向量
126 }
127
128 }
129
130 //保持与头儿的距离
131 f = d/followRadius;
132 UnityFlock otherSealgull = otherFlocks[i];
133
134 //标准化otherSealgul的速度来获取移动的方向，接下来设置一个新的速度
135 avgVelocity += otherSealgull.normalizedVelicity * f *followVelocity;
136
137 }
138 }
139
140 if (count > 0)
141 {
142 //得到平均速度
143 avgVelocity /= count;
144 //获得平均位置与对象间的向量
145 toAvg = (avgPosition/count) - myPosition;
146 }
147 else
148 {
149 toAvg = Vector3.zero;
150 }
151
152 //
153 forceV = origin.position - myPosition;
154 d = forceV.magnitude;
155 f = d/toOriginRange;
156 //
157 if (d > 0)
158 originPush = (forceV/d)*f*toOriginForce;
159 if (speed < minSpeed && speed > 0)
160 velocity = (velocity/speed)*minSpeed;
161
162 wantedVel = velocity;
163
164 //最终速度
165 wantedVel -= wantedVel*Time.deltaTime;
166 wantedVel += randomPush*Time.deltaTime;
167 wantedVel += originPush*Time.deltaTime;
168 wantedVel += avgVelocity*Time.deltaTime;
169 wantedVel += toAvg.normalized*gravity*Time.deltaTime;
170
171 //调整速度使之转向最终速度
172 velocity = Vector3.RotateTowards(velocity, wantedVel,turnSpeed*Time.deltaTime, 100.00f);
173
174 transformCompont.rotation = Quaternion.LookRotation(velocity);
175
176 //移动对象
177 transformCompont.Translate(velocity*Time.deltaTime,Space.World);
178
179 //跟新标准化向量的引用
180 normalizedVelicity = velocity.normalized;
181 }
182
183
184
185 }
群组控制器（头鸟）：
1 using UnityEngine;
2 using System.Collections;
3
4 /// <summary>
5 /// 头鸟决定飞行的整体方向，在unityflock中被origin引用
6 /// </summary>
7 public class UnityFlockController : MonoBehaviour
8 {
9
10 public Vector3 offset;//偏移
11 public Vector3 bound;//范围
12 public float speed = 100.0f;
13
14 private Vector3 initialPosition;
15 private Vector3 nextMovementPoint;
16
17 //
18
19 // Use this for initialization
20 void Start ()
21 {
22 initialPosition = transform.position;
23 CalculateNextMovementPoint();
24 }
25
26 // Update is called once per frame
27 void Update () {
28 transform.Translate(Vector3.forward*speed*Time.deltaTime);
29 transform.rotation=Quaternion.Slerp(transform.rotation,Quaternion.LookRotation(nextMovementPoint-transform.position),1.0f*Time.deltaTime );//调整飞行角度
30
31 if(Vector3.Distance(nextMovementPoint,transform.position)<=10.0f)
32 {
33 CalculateNextMovementPoint();
34 }
35
36 }
37
38 void CalculateNextMovementPoint()
39 {
40 float posx = Random.Range(initialPosition.x - bound.x, initialPosition.x + bound.x);
41 float posy = Random.Range(initialPosition.y - bound.y, initialPosition.y + bound.y);
42 float posz = Random.Range(initialPosition.z - bound.z, initialPosition.z + bound.z);
43
44 nextMovementPoint = initialPosition + new Vector3(posx, posy, posz);
45 }
46 }
效果：
时间： 2024-12-25 05:43:34