Can't figure out Physics.OverlapSphere

Unity Engine
1

Hello,

I’m trying to add a feature where if the “z” key is hit, all enemies in a certain radius will be alerted. I think Physics.OverlapSphere is the best way to do this, but I cannot figure out how to implement it. I am using JS, and here are my scripts:

This is what I am using for pressing the ‘Z’ key, which causes the player to whistle

function Update () {
	if (Input.GetKeyDown ("z"))
        Whistle();
}

After Z is hit, all objects with the layer ‘Enemy’ that are within the radius of 100 should begin “AttackPlayer” - But I don’t know what I am doing wrong. I do not know how to search for ‘layer’ - I am just stabbing in the dark.

function Whistle()//added
{
var colliders : Collider[] = Physics.OverlapSphere(transform.position, 100.0);

for (var col : Collider in colliders)

    {

      if (col.collider.layer== "Enemy")

      {

           col.gameObject.SendMessage("AttackPlayer");

      }

    }
 
}
2

I thought “layer” is an int, not a string. Compare layer to LayerMask.NameToLayer(“Enemy”) instead. (optimize it later though after you get it working)

3

layers are bitmasks. You would have to use bitwise operators (1 << 20; for example) to access the layers.

Tags would be more appropriate for this situation, I think.

4

Using Layers would work well here but instead of checking the layer afterwards.
You can let the Physics.OverlapSphere call only return items of a specific layer.

Check the documentation: Unity - Scripting API: Physics.OverlapSphere
OverlapSphere (position : Vector3, radius : float, layerMask : int = kAllLayers) : Collider[ ]

This way you know you only have enemys and don’t need to compare them.

5

you could always use tags in this situation

 if (col.collider.layer== "Enemy")

try this

 if (col.gameObject.tag== "Enemy")
6

What Joshimoo said. Create a public variable called enemyLayer : LayerMask, it will create a dropdown in the inspector that you can pick the enemy layer from. Then pass the mask into the OverlapSphere call.

var enemyLayer : LayerMask; //set this in the editor

function Whistle(){
    var colliders : Collider[] = Physics.OverlapSphere(transform.position, 100.0, enemyLayer);
    for (var col : Collider in colliders){ 
        if (col.collider.layer== "Enemy")
            col.gameObject.SendMessage("AttackPlayer");
    }
}

If you just want to hard code it and you don’t want to set it as an inspector variable, you can use

LayerMask.NameToLayer("Enemy")