Question pick a random object from the array if it is within some range

Hello! I have an array of enemies. I want to select a random enemy, but if it is within some distance of the player.
Here is my script for the random enemy:

Code (CSharp):

1. public GameObject RandomEnemy()
2.     {
3.         GameObject[] gos;
4.         gos = GameObject.FindGameObjectsWithTag("Enemy");
5.         if (gos.Length != 0) { random = gos[Random.Range(0, gos.Length)]; }
6.         return random;
7.  
8.     }

But I need something like this:

Code (CSharp):

1. if (Vector3.Distance(playerPosition, go.transform.position) < someRange)

and before I set "random" otherwise sometimes I will not receive anything from the array
Could you help me?

 

Once you determine the range you want to use for detection, you should attempt to gather all enemies in that range. Then create a collection of only those enemies. There are different ways to do so. But if you have that collection, you can pick a random one from it.

 

Thanks for the reply. I understand what needs to be done but I don't know how. That is the problem . I am a very inexperienced programmer.
Could you tell me how to do it? Interested in the most inexpensive method, since there can be a lot of enemies. I would really appreciate it.

 

Without knowing if the game is 2d or 3d, usually when you want to find something with respect to a point, you use raycasts or overlaps checks with the Physics/Physics2D classes. In the case of wanting to find a certain enemy within range, you would probably use an overlap Sphere/Circle:
3d: https://docs.unity3d.com/ScriptReference/Physics.OverlapSphere.html
2d: https://docs.unity3d.com/ScriptReference/Physics2D.OverlapCircleAll.html

You can use that to easily find all enemies within a range around the player, then it's just a matter or selecting a random entry from the results. There's an infinite number of tutorials out there on how to use raycasts/overlaps.

 

Thank you. This is a 3D game.

OK, I can find all enemies. Let it be array 'gos'. And I can find all "go" from "gos" that are within the range around the player. How do I put all these valid "go" into a new array ( "validCos")?

 

Please read my post again.

Use OverlapSphere to get all enemies within a certain range. Ideally you put enemies all on their own layer, and use a layer mask to only receive results on that layer. The method returns a collection of colliders, of which you can use

GetComponent<T>

to get whatever component you care about to deal damage or whatever.

Like I said. Lots of tutorials out there on raycasts/overlap stuff.

There's no need to use

GameObject.FindGameObjectsWithTag

or similar when you can just use an overlap sphere to find every enemy within the desired range.

 

If I use OverlapSphere I will get not only enemies but other objects with collider too. Then I can choose only enemies ( GetComponent<Enemy>).
But how can I choose random enemy then? That is what I can't realize.

 

As mentioned there's various ways to filter the results of an overlap sphere, such as using a LayerMask. Plenty of info on it in the docs: https://docs.unity3d.com/Manual/Layers.html

When you have a collection of something, either a list of an array, you can access their elements via a numerical index. You just need to make a random number from 0 to the one less than the number of elements in your collection (as collections in C# are zero-index based).

Honestly it's only three lines of code:

Code (CSharp):

1. Collider[] enemyColliders = Physics.OverlapSphere(transform.position, radius, enemyLayerMask);
2. int randomIndex = UnityEngine.Random.Range(0, enemyColliders.Length);
3. Collider randomEnemyCollider = enemyColliders[randomIndex];

 

Thanks for the answer and your patience I just didn't want to use layers and was looking for an alternative way. But now I see that the method you suggested was much easier.