koobas.hobune.stream
2D LookAt not working as intended
So I have looked this up and found http://www.dphsw.co.uk/blog/?p=172, but when I try it out, it did not work for me so I had to add a line so that the sprite would be visible. There is still a problem with it, here is an image of the problem. What am I doing wrong? 
using UnityEngine;
using System.Collections;
public class Target : MonoBehaviour
{
private Transform target;
private RaycastHit2D hit;
// Use this for initialization
void Start ()
{
}
// Update is called once per frame
void Update ()
{
if (!target)
{
hit = Physics2D.Raycast(transform.position, Vector2.up);
Debug.DrawRay(transform.position, Vector2.up);
}
if (target)
{
hit = Physics2D.Raycast(transform.position, target.position - transform.position);
Debug.DrawRay(transform.position, target.position - transform.position);
var direction = target.position - transform.position;
transform.LookAt(Vector3.forward, direction); //target has to be 0,0,1 in order for it to be visible.
transform.rotation = new Quaternion(0, 0, transform.rotation.z, transform.rotation.w);
}
}
void OnTriggerEnter2D(Collider2D other)
{
if (other.gameObject.tag == "Enemy" && !target)
{
target = other.gameObject.transform;
}
}
void OnTriggerExit2D(Collider2D other)
{
if (other.gameObject.transform == target)
{
target = null;
}
}
}
Best Answer
The best thing for a sprite is to make the texture so that the front is on the right. Then you can do this:
if (target)
{
hit = Physics2D.Raycast(transform.position, target.position - transform.position);
Debug.DrawRay(transform.position, target.position - transform.position);
Vector3 direction = target.position - transform.position;
float angle = Mathf.Atan2(direction.y, direction.x) * Mathf.Rad2Deg;
transform.rotation = Quaternion.AngleAxis(angle, Vector3.forward);
}
So using Atan2 is okay? I am planning on having like 500 of these things on the screen, would performance be okay using Atan2?
There are other ways to solve this rotation, but I doubt they are any more efficient than this one. I doubt that Atan2() will play any role in performance issues you have with 500 objects.
