Cannot convert 'UnityEngine.Collider[]' to 'UnityEngine.gameObject[]' using OverlapSphere

Questions & Answers
1

Hi

I am trying to make a more versatile way of entering vehicles I kinda am trying to “soft code” it instead of “hard coding” it like I did in the past.

var radius = 3.0;
function FindClosestVehicle(){
    
    var gameObjects : GameObject[] = Physics.OverlapSphere (transform.position,radius); // Error here
    
    for (var hit : GameObject in gameObjects) {
        if (!hit)
            continue;
        
        if (hit.gameObject){
            print(hit.gameObject.name);
           
    }
}
}

But is says “Cannot convert ‘UnityEngine.Collider’ to ‘UnityEngine.gameObject’” At the third line of code. I cannot see any collider information there unless OverlapSphere is only for collecting colliders. If so how would one go about finding gameObject using Physics.OverlapSphere?

Thank you my friend.

2

The physics system only works with colliders so [OverlapSphere][1] returns an array of colliders which bounds touches the sphere. An array of Colliders can’t be “casted” or “converted” into a GameObject array. You have to do it manually.

Colliders are components so they are always attached to a GameObject. To access this GameObject you can just use .gameObject on a collider.

Btw. in your for loop you have useless redundancy. The hit variable is of type GameObject so hit.gameObject is the same as hit.

However OverlapSphere doesn’t return a GameObject array so you should change your code like this:

var colliders : Collider[] = Physics.OverlapSphere (transform.position,radius);

for (var current : Collider in colliders)
{
    print(current.name);
    // To access the GameObject of that collider use:
    // current.gameObject
}

Oh and all Components attached to a GameObject share the gameobjects name, tag and layer so you don’t need to use current.gameObject.name
[1]: http://unity3d.com/support/documentation/ScriptReference/Physics.OverlapSphere.html

3

it’s all but elegant, but I think you could do something along the line of

var colliders : Collider[] = Physics.OverlapSphere (transform.position,radius);
var gameObjects : GameObject[];
for (var col : Collider in colliders)
{
  gameObjects.Add(col.gameObject);
}

[untested code!]

It should work, but there has to be a nicer way…?

Edit: Aw, Bunny was faster =3 … so there’s no other way after all o.o

Greetz, Ky.

4

A nice looking approach is to convert the whole array using a converter.

var radius = 3.0;
function FindClosestVehicle(){

    var colliders = Physics.OverlapSphere (transform.position,radius);
    var gameObjects = System.Array.ConvertAll.<Collider , GameObject>( colliders , function(x) x.gameObject );

    for (var hit : GameObject in gameObjects) {
        if (!hit)
            continue;

        if (hit.gameObject){
            print(hit.gameObject.name);

    }
}
}

The nice thing about that is you don’t have to rewrite your enumerator since you will have a gameObject array. there will be no need to change the enumerator to change the collider to a game object in the loop.

Note: I don’t know if you can use generic methods in js. I know generic types work, but I’ve never tried generic methods so I’m writing it in C# too

float radius = 3.0f;
public void FindClosestVehicle(){

    var colliders = Physics.OverlapSphere (transform.position,radius);
    var gameObjects = System.Array.ConvertAll<Collider , GameObject>( colliders , x => x.gameObject );

    for (var hit  in gameObjects) {
        if (hit == null)
            continue;

        else {
            print(hit.name);

    }
}
}