5.随机徘徊

我们希望场景中有随机移动的单位,如巡逻的士兵 吃草的牛羊,往往我们在场景中设置几个点让单位在几个点中随机移动,这样会出现一种情况,单位突然掉头,Craig Reynolds突出的随机徘徊解决了这个问题

public class SteeringForWander : Steering {
    public float wanderRadius;//Wander半径
    public float wanderDistance;//Wander距离
    public float wanderJitter;//每秒加到随机位移的最大值
    
    
    private Vector3 desiredVelocity;
    private Vehicle m_vehicle;
    private float maxSpeed;
    private Vector3 circleTarget;
    private Vector3 wanderTarget;
    // Use this for initialization
    void Start () {
        m_vehicle = GetComponent<Vehicle>();
        maxSpeed = m_vehicle.maxSpeed;
        //选圆上一个点作为初始点
        circleTarget = new Vector3(wanderRadius * 0.5f, 0, wanderRadius * 0.3f);

    }

    public override Vector3 Force()
    {
        //随机位移
        Vector3 randomDisplacement = new Vector3((Random.value - 0.5f) * 2 * wanderJitter, 0, (Random.value - 0.5f) * 2 * wanderJitter);
        //从初始点加上一个随机位移
        circleTarget += randomDisplacement;
        //将得到的新点进行投射到圆弧上
        circleTarget = wanderRadius * circleTarget.normalized;
        wanderTarget = m_vehicle.velocity.normalized * wanderDistance + circleTarget + transform.position;
        desiredVelocity = (wanderTarget - transform.position).normalized * maxSpeed;
        return desiredVelocity - m_vehicle.velocity;
    }
}

Wander.gif

6.避开障碍

通过在AI前方发射一条一定长度的射线来检测AI前方是否有需要躲避的物体,在有障碍时,我们给AI一个向量为向前方的向量加上障碍中心到AHead的向量,来让AI物体避开障碍.

public class SteeringForCollisionAvoidance : Steering {
    public Vehicle m_vehicle;
    private float maxSpeed;

    Vector3 desiredVelocity;
    float maxForce;
    //避免障碍的力
    public float avoidanceForce;
    public float MAX_SEE_AHEAD = 2.0f;

    GameObject[] allColliders;
    
    
    // Use this for initialization
    void Start () {
        m_vehicle = GetComponent<Vehicle>();
        maxSpeed = m_vehicle.maxSpeed;
        maxForce = m_vehicle.maxForce;
        if(avoidanceForce > maxForce)
        {
            avoidanceForce = maxForce;
        }
        allColliders = GameObject.FindGameObjectsWithTag("obstacle");
    }

    public override Vector3 Force()
    {
        RaycastHit hit;
        Vector3 force = new Vector3(0, 0, 0);
        Vector3 velocity = m_vehicle.velocity;
        Vector3 normalizedVelocity = velocity.normalized;
        //从AI向前发射一条射线,如果在需要避开障碍的范围内,进行当前前方加一个原点到前方的向量和来作为新的力
        if (Physics.Raycast(transform.position,normalizedVelocity,out hit, MAX_SEE_AHEAD * velocity.magnitude / maxSpeed))
        {
            Vector3 ahead = transform.position + normalizedVelocity * MAX_SEE_AHEAD * (velocity.magnitude / maxSpeed);
            force = ahead - hit.collider.transform.position;
            force *= avoidanceForce;
        }
        return force;
    }
}

CollisionAvoidance.gif