transform.LookAt() 问题

Question

I am trying to make an AI that will follow the closest object, but the problem is that when the object gets close it will rotate vertically, which I think is because the transform.LookAt() rotates towards the center of the object. Is there a way to look at an object without rotating vertically? Here's the code for the AI

using System.Collections.Generic;
using UnityEngine;

public class AI : MonoBehaviour
{
    [SerializeField] public float speed = 2f;

    public float SphereRadius;
    public LayerMask mask;

    private void FixedUpdate()
    {
        //Checks if theres any objects nearbye
        Collider[] hitColliders = Physics.OverlapSphere(transform.position, SphereRadius, mask, QueryTriggerInteraction.UseGlobal);
        //Gets all the transforms of the objects and stores them into an array
        List<Transform> Transforms = new List<Transform>();
        foreach (var hitCollider in hitColliders)
        {
            Transforms.Add(hitCollider.transform);
        }
        //Checks what's the closest object and rotates the AI towards that object
        transform.LookAt(
        GetClosestEnemy(
            Transforms.ToArray()
        ) 
        );
        transform.Translate(Vector3.forward * speed * Time.deltaTime);
    }

    Transform GetClosestEnemy(Transform[] enemies)
    {
        Transform tMin = null;
        float minDist = Mathf.Infinity;
        Vector3 currentPos = transform.position;
        foreach (Transform t in enemies)
        {
            float dist = Vector3.Distance(t.position, currentPos);
            if (dist < minDist)
            {
                tMin = t;
                minDist = dist;
            }
        }
        return tMin;
    }
}

Answer 1

Instead of directly using the Transform overload use the one taking a Vector3 target position you can completely customize like eg

var target = GetClosestEnemy(Transforms.ToArray());

var localDelta = transform.InverseTransformPoint(target.position);
// Now you can reset any of the axis you do not want to be taken into account e.g.
localDelta.z = 0;

transform.LookAt(transform.TransformPoint(localDelta));

---

Btw as a little tip magnitude (which is internally used by Vector3.Distance ) is significantly slower than the sqrMagnitude as the latter skips taking the square root.

For comparison both work the same so you can use

Transform GetClosestEnemy(IEnumerable<Transform> enemies)
{
    Transform tMin = null;
    float minDist = Mathf.Infinity;
    Vector3 currentPos = transform.position;
    foreach (Transform t in enemies)
    {
        float dist = (t.position - currentPos).sqrMagnitude;
        if (dist < minDist)
        {
            tMin = t;
            minDist = dist;
        }
    }
    return tMin;
}

or if you re a fan of Linq you could also do

Transform GetClosestEnemy(IEnumerable<Transform> enemies)
{
    Vector3 currentPos = transform.position;
    return enemies.OrderBy(enemy => (enemy.position - currentPos).sqrMagnitude).FirstOrDefault();
}

Then you could also shrink down the rest and do

Collider[] hitColliders = Physics.OverlapSphere(transform.position, SphereRadius, mask, QueryTriggerInteraction.UseGlobal);
var target = GetClosestEnemy(hitColliders.Select(collider => collider.transform));