Unity3D射线检测墙面前停止移动

功能：

计算角色/怪物走到目标，如果有墙就再墙前停止，防止一直怼墙走现象。

思路:

1. 求角度 = 反入射线 与 法线 的夹角度

2. cos角度 = 自身宽度 / 距墙停止距离

3. 距墙停止距离 = 自身宽度 / cos角度

4. |应走向量| = |走到墙前向量| -  距墙停止距离

5. 应走向量 = 到墙向量.单位向量 *  |应走向量|

图文待更新

限制：

①不能是斜着的墙或人

②地形是平面

③不能太小的阻挡物

实验截图：

橙色圆柱是角色，绿色是要走到的目标位置，计算结果是灰色圆柱

   

    

上码：

public class test : MonoBehaviour
{
    public GameObject Self;
    public GameObject Fake;
    public GameObject Target;
    public float width;

    public float rayAngle;
    public float rayDirectValue;
    public float realGetLenght;
    public Vector3 rayVector;
    public Vector3 realGetVector;

    public float offerAngle;
    public float offerSin;
    public float offerCos;
    public float offerXValue;
    public float offerZValue;

    void Start()
    {
        width = Self.GetComponent<CapsuleCollider>().radius * Self.transform.localScale.x;
    }

    void Update()
    {
        Vector3 wantPos = Target.transform.position;
        Vector3 realGetPos = Vector3.zero;
        RaycastHit raycastHit = new RaycastHit();
        Ray wallCheck = new Ray(Self.transform.position, Target.transform.position - Self.transform.position);
        if (Physics.Raycast(wallCheck, out raycastHit, Vector3.Distance(Target.transform.position, Self.transform.position) + 8, 1 << LayerMask.NameToLayer("Ground")))
        {
            rayAngle = Vector3.Angle(Self.transform.position - Target.transform.position, raycastHit.normal);
            rayDirectValue = width / Mathf.Cos(Mathf.PI / 180 * rayAngle);
            rayVector = raycastHit.point - Self.transform.position;
            realGetLenght = rayVector.magnitude - rayDirectValue;           
            realGetVector = rayVector.normalized * realGetLenght;
            realGetPos = new Vector3(
                    Self.transform.position.x + realGetVector.x,
                    Self.transform.position.y,
                    Self.transform.position.z + realGetVector.z);
        }
        else
            realGetPos = wantPos;
        
        Fake.transform.position = realGetPos;
        Debug.DrawLine(Self.transform.position, wantPos, Color.red);
        Debug.DrawLine(Self.transform.position, realGetPos, Color.blue);
    }
}