Line of sight for multiple targets - AI - in a 2d game

Questions & Answers
1

Hi I am making a multiplayer game. And I would like my monsters to shoot at any player who gets within their line of sight and if multiple players are within the line of sight, I would like them to shoot at the closest one.

What I have tried doing so far was to create a dictionary of players that enter the monsters area collider and update their positions in ontriggerstay. and then cast rays at said locations and check if it hits. This has not worked well at all.

I am wondering if there is a simpler solution to this problem.

I have read up on raycasts quite a bit and it would be simple if all I had to do was hit one player and on eplayers only, but I get stumped when there are many different players that the monster can chose from.

public void OnTriggerEnter2D(Collider2D other)
    {
        if (other.tag == "player")
        {
            aggro = true;

            if (!playersInLineOfSight.ContainsKey(other.gameObject.name))
            {
                playersInLineOfSight.Add(other.gameObject.name, other.gameObject.transform.position);
            }
        }
    }

Then I run method during aggro:

public void RayLogic() {

foreach (KeyValuePair<string, Vector3> player in playersInLineOfSight)
        {
            var playerName = player.Key;
            var playerLoc = player.Value;
            var dir = (playerLoc - transform.position).normalized;
            float distanceToPlayer = Vector2.Distance(transform.position, playerLoc);

            RaycastHit2D hit = Physics2D.Raycast(transform.position, playerLoc - transform.position, distanceToPlayer);
            if (hit.transform.tag == "enemy")
                continue;
            if (hit.transform.tag == "Untagged")
                continue;

            if (hit.transform.tag == "wall")
            {
                Debug.Log("I see a wall");
            }

            if (hit.transform.tag == "otherPlayer")
            {
                Debug.Log("I see a player");
            }

            Debug.Log("hit on: " + hit.transform.tag);
            Debug.DrawRay(transform.position, dir, Color.red);

        }

    }

It seems to have very small range but I can get it to log “I see a player” if I stand right on top of the enemy.

any help would be greatly appreciated.

2

Ok I managed to figure it out:

public void RayLogic() {

        foreach (KeyValuePair<string, GameObject> player in playersInLineOfSight)
        {
            var playerLoc = player.Value.transform.position;
            var dir = (playerLoc - transform.position).normalized;
            float distanceToPlayer = Vector3.Distance(transform.position, playerLoc);

            Debug.DrawRay(transform.position, dir * 10000f, Color.red); // makes a long line which is easier to use

            RaycastHit2D[] hits = Physics2D.RaycastAll(transform.position, dir, distanceToPlayer);

            foreach (RaycastHit2D hit in hits)
            {
                if (hit.transform.tag == "enemy")  // som tags I need to ignore in my game
                    continue;
                if (hit.transform.tag == "Untagged")
                    continue;
            }

            if (hits.Length > 0)
            {
                   if (hits[0].transform.tag == "player")
                  {
                          // do something
                  }
            }
        }

    }