【AI】角色的自主移动（2）——靠近、离开、抵达、追逐、逃避

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
/// <summary>
/// 靠近
/// </summary>
public class SteeringForSeek :Steering {


    //目标物体
    public GameObject target;

    //预期速度
    private Vector3 desiredVelocity;

    //获取AI角色
    private Vehicle m_vehicle;

    //最大 速度
    private float maxSpeed;

    //是否在2d平面
    private bool isPlanar;

    void Start()
    {
        m_vehicle = GetComponent<Vehicle>();
        maxSpeed = m_vehicle.maxSpeed;
        isPlanar = m_vehicle.isPlanar;
    }

   //计算力
    public override Vector3 Force()
    {
      
        desiredVelocity=(target.transform.position-transform.position).normalized*maxSpeed;
        if (isPlanar)
        {
            desiredVelocity.y=0;
    
        }
        return (desiredVelocity - m_vehicle.velocity);
    }
}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
/// <summary>
/// 离开
/// </summary>
public class SteeringForFlee : Steering{

    public GameObject target;

    //设置危险距离
    public float fearDistance = 20;

    private Vector3 desiredVelocity;
    private Vehicle m_vehicle;
    private float maxSpeed;

    void Start()
    {

        m_vehicle = GetComponent<Vehicle>();
        maxSpeed = m_vehicle.maxSpeed;
    }

    public override Vector3 Force()
    {
        Vector3 tmpPos = new Vector3(transform.position.x, 0, transform.position.z);
        Vector3 tmpTargetPos = new Vector3(target.transform.position.x, 0, target.transform.position.z);

        //如果大于逃跑距离，那么返回向量0

        if (Vector3.Distance(tmpPos,tmpTargetPos)>fearDistance)
        {
            return new Vector3(0, 0, 0);
        }

        //如果小于 计算

        desiredVelocity = (transform.position - target.transform.position).normalized * maxSpeed;

        return (desiredVelocity - m_vehicle.velocity);

       
    }
}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
/// <summary>
/// 抵达
/// </summary>
public class SteeringForArrive : Steering
{


    public bool isPanar = true;
    public float arrivalDistance = 0.3f;
    public float characterRadius = 1.2f;

    //当与目标小于这个距离时，开始减速

    public float slowDownDistance;
    public GameObject target;
    private Vector3 desiredVelocity;
    private Vehicle m_vehicle;
    private float maxSpeed;



    void Start()
    {

        m_vehicle = GetComponent<Vehicle>();
        maxSpeed = m_vehicle.maxSpeed;
        isPanar = m_vehicle.isPlanar;
    }

    public override Vector3 Force()
    {


        //角色与目标的距离
        Vector3 toTarget = target.transform.position - transform.position;

        //预期速度
        Vector3 desiredVelocity;

        Vector3 returnForce;
        if (isPanar)
        {
            toTarget.y = 0;
        }

        float distance = toTarget.magnitude;
        //大于减速半径
        if (distance > slowDownDistance)
        {
            desiredVelocity = toTarget.normalized * maxSpeed;

            returnForce = desiredVelocity - m_vehicle.velocity;
        }
        else
        {
            desiredVelocity = toTarget - m_vehicle.velocity;
            returnForce = desiredVelocity - m_vehicle.velocity;

        }
        return returnForce;
    }


    void OnDrawGizmos()
    {
        //在目标范围画白色线框
        Gizmos.DrawWireSphere(target.transform.position, slowDownDistance);
    }

}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
/// <summary>
/// 追逐
/// </summary>
public class SteeringForPursuit : Steering {

    public GameObject target;
    private Vector3 desiredVelocity;
    private Vehicle m_vehicle;
    private float maxSpeed;

    void Start()
    {
        m_vehicle = GetComponent<Vehicle>();
        maxSpeed = m_vehicle.maxSpeed;
    }
    public override Vector3 Force()
    {
        Vector3 toTarget = target.transform.position - transform.position;
        //计算追逐者前向与逃避者前向的夹角
        float relativeDirection = Vector3.Dot(transform.forward, target.transform.forward);

        //如果夹角大于0，且面对
        if ((Vector3.Dot(toTarget,transform.forward)>0)&&(relativeDirection<-0.95f))
        {
            //计算预期速度
            desiredVelocity = (target.transform.position - transform.position).normalized * maxSpeed;
            //返回向量
            return (desiredVelocity - m_vehicle.velocity);
        }
        //计算预测时间，距离/速度和

        float lookaheadTime = toTarget.magnitude / (maxSpeed + target.GetComponent<Vehicle>().velocity.magnitude);

        //计算预期速度
        desiredVelocity = (target.transform.position + target.GetComponent<Vehicle>().velocity * lookaheadTime - transform.position).normalized * maxSpeed;



        return (desiredVelocity - m_vehicle.velocity);
    }
}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
/// <summary>
/// 逃避
/// </summary>
public class SteeringForEvade : Steering {

    public GameObject target;
    private Vector3 desiredVelocity;
    private Vehicle m_vehicle;
    private float maxSpeed;
    void Start()
    {
        m_vehicle = GetComponent<Vehicle>();
        maxSpeed = m_vehicle.maxSpeed;
    }

    public override Vector3 Force()
    {
        Vector3 toTarget = target.transform.position - transform.position;
        //预测时间
        float lookaheadTime = toTarget.magnitude / (maxSpeed + target.GetComponent<Vehicle>().velocity.magnitude);

        //计算预期速度
        desiredVelocity = (transform.position - (target.transform.position + target.GetComponent<Vehicle>().velocity * lookaheadTime)).normalized * maxSpeed;

        //返回操控向量
        return (desiredVelocity - m_vehicle.velocity);
    }
    
}