在特定距离和角度内选择GameObjects

Question

所以我理解所涉及的数学，对如何实现它有点困惑。我已经抓住了一定距离的游戏对象：

        GameObject[] nodesInView = GameObject.FindGameObjectsWithTag ("Node");
        List<GameObject> listOfNodesInView = new List<GameObject> ();
        foreach (GameObject node in nodesInView) {
            float dist = (player.transform.position - node.transform.position).magnitude;
            if(dist < 100)
            {
                listOfNodesInView.Add (node);
            }

        }

但这给我的是一个360度的角度：

请原谅我的绘画，但它正在说明它在做什么。但是现在，我如何根据角度变量限制搜索？

* EDIT Theta =我选择的值，而不是值选择。

同样重要的是要知道红点代表原点，绿色代表收集的内容，橙色代表节点

Answer 1

要搜索一定距离内的游戏对象，角度我搞砸了很多，找到了我觉得有效的解决方案：

    GameObject[] nodesInView = GameObject.FindGameObjectsWithTag ("Node");
    List<GameObject> listOfNodesInView = new List<GameObject> ();
    foreach (GameObject node in nodesInView) {
        float dist = (player.transform.position - node.transform.position).magnitude;
        if(dist < 300)
        {
            Vector3 dir = player.transform.position - node.transform.position;
            float angle = Mathf.Atan2 (dir.z, dir.x) * Mathf.Rad2Deg;
            if(angle > 45 && angle < 120)
                listOfNodesInView.Add (node);
        }

    }

这是在一定距离内搜索两个角度之间的游戏对象。 （见第二张图片）

Answer 2

这是我使用的：

// From me to another game object returns it's distance and relative angle I'd need to turn to face it
private bool CalculateDistanceAndDirectionToTarget(Transform target, out float distance, out float angle)
{
    if (target == null) { return false; }

    // distance from me
    distance = Vector3.Distance(transform.position, target.position);

    // angle from me
    Vector3 deltaPosition = target.position - transform.position;
    // Get the delta angle from our current forward to turn towards the target. 
    // Note: This is an absolute value and the smallest angle
    // Ref: http://answers.unity3d.com/questions/376921/im-having-problems-checking-of-my-ai-can-see-me-c.html
    float angle = Vector3.Angle(deltaPosition, transform.forward);
    // To determine if we need to turn left/right, use the cross product to calculate the sign
    // Ref: http://answers.unity3d.com/questions/181867/is-there-way-to-find-a-negative-angle.html
    Vector3 cross = Vector3.Cross(deltaPosition, transform.forward);
    if (cross.y < 0)
    {
        angle = -angle;
    }

    return true;   
}

// Determine if I can see the target given a distance and angle I can see
public bool IsWithinSight(Transform target, float maxDistance, float maxAngle)
{
    float angle = 0f;
    float distance = 0f;

     if (CalculateDistanceAndDirection(target, out distance, out angle))
     {
            if (distance < maxDistance && Mathf.Abs(angle) < maxAngle)
            {
                return true;
            }
    }

    return false;
}

然后你可以循环浏览某种类型的所有游戏对象。