我在Unity 3D中遇到了一个奇怪的问题。我的想法是从阵列中找到距离玩家最近和第二最近的对象。然后我想让相机移动到最近的物体的位置，看着播放器，但是如果播放器和最近的物体之间的距离太小，我想让相机移动到第二个物体的位置。我做了一些编码，我不知道为什么else-if的第三部分甚至没有执行。当玩家离得太近时，相机不会切换，而是保持最近的物体位置。
public class Robot2 : MonoBehaviour
{
public GameObject cameraHolder;
public Transform[] objects;
private Transform nearestObj;
private Transform secondObj;
void Update()
{
float lowestDist = 9999f;
float secondLowestDist = lowestDist + 1f;
float tooCloseDist = 3f;
nearestObj = null;
secondObj = null;
foreach(Transform obj in objects)
{
float dist = Vector3.Distance(transform.position, obj.position);
if(dist < lowestDist)
{
lowestDist = dist;
nearestObj = obj;
cameraHolder.transform.position = nearestObj.transform.position;
}
else if(dist < secondLowestDist)
{
secondLowestDist = dist;
secondObj = obj;
}
else if(dist < tooCloseDist)
{
Debug.Log("Too close , switching");
cameraHolder.transform.position = secondObj.transform.position;
}
}
Debug.DrawLine(transform.position, nearestObj.transform.position, Color.red);
}
}
如果第二个对象也太近怎么办？
在使用和访问第一个和第二个最近的对象之前，为了获得更一般的解决方案，我将首先遍历整个阵列，看看是否真的没有更接近的对象。
您可以使用LinqOrderBy，并使用（transform.position-obj.position）作为标准。SQR幅度比使用幅度更便宜（这是矢量3.距离使用的）
using System.Linq;
...
[SerializeField] float tooCloseDist = 3f;
// Just a little helper struct, could also use a tuple
// but this is probably easier to understand
private struct DistanceInfo
{
public readonly Transform transform;
public readonly float sqrDistance;
public DistanceInfo(Transform self, Transform target)
{
transform = target;
sqrDistance = (self.position - target.position).sqrMagnitude;
}
}
private void Update ()
{
// It's cheaper to use squared magnitude of vectors if it is only about comparing them
var tooCloseDistanceSqr = tooCloseDistance * tooCloseDistance;
// In one go for each object get according distance info instance
// and order them starting with the smallest distance
var orderedByDistance = objects.Select(obj => new DistanceInfo (transform, obj)).OrderBy(info => info.sqrDistance);
// Go through the sorted instances of DistanceInfo
foreach(var info in orderedByDistance)
{
// since we ordered by distance "info" is always the next closest object
// if it is too close -> skip to the next closest one
if(info.sqrDistance < tooCloseDistanceSqr) continue;
// we found the next closest object that is not too close
cameraHolder.transform.position = info.transform.position;
Debug.DrawLine(transform.position, info.transform.position, Color.red);
// break the loop as we don't want to do anything further
break;
}
}
