How do I implement melee hit boxes for a top-down game?

Question

For a 3D top-down game, how should I handle collision in melee combat? My game has no targeting system, so I can't use a simple distance check between attacker and target.

What I am thinking is have the character swing, generate a hit box, run the damage script for any characters in that hit box, and then delete the hit box. How should I handle this?

Also, I would like to use the same attack script for all players and NPCs in melee, even with different attack animations and hit boxes. However, really I can't figure out how to reliably assign who the attacker and who the target are within that script, or how to handle multiple simultaneous attacks.

Answer 1

I think you and the commenters are on the right track. Ideally the hitboxes wouldn't have to be recreated on each attack (unless the nature of the attack were to change, maybe?). You could add something like this to every GameObject that can attack, along with a hitbox Collider marked as a Trigger.

public class HitController : MonoBehavior {

private Queue hitQueue;
private int health;
private int damage;
private bool attacking;

public void Start() {
    hitQueue = new Queue();
    health = 10;
    damage = 3;
    attacking = false;
}

public void Update() {
    // rudimentary attack input..
    if (Input.GetKeyDown(KeyCode.Space)) {
        // play an animation, etc...
        attacking = true;
    } else {
        attacking = false;
    }
    //  ...
    HandleHits();
    //  ...
}

private void HandleHits() {
    if (hitQueue.Count > 0) {
        Hashtable hitData = hitQueue.Dequeue();
        string name = hitData["name"];
        // do something with the attacker's name if you like
        int dmg = hitData["damage"];
        // could do further processing with attacker's damage..
        health -= dmg;
        if (health <= 0) {
            //however you wanna handle this
        }
    }
}

public void SignalHit(Hashtable hitData) {
    hitQueue.Enqueue(hitData);
}

public void OnTriggerEnter(Collider c) {
    // we only care about collisions if we're attacking
    if (attacking) {
        HitController hc = c.gameObject.GetComponent<HitController>();
        // this will hit other HitControllers, but not handle other collisions
        if (hc != null) {
            Hashtable h = new Hashtable();
            h.Add("name", this.name);
            h.Add("damage", this.damage);
            hc.SignalHit(h);
        }
    }
}
}