Find the closest gameobject ?

Scripting
1

Ok, I have a Ai script that need to find the closest gameobject that is tagged by “Enemy”.

How should I do this ?

Raycast all around and find objects and store them in a array. How to find the closest object from the transfrom.position in the Array ?

OR another way to do this ?

2

Hi ,

why raycasting around if you already tagged your enemies ? You could just iterate through them with

// Quick Pseudocode

var allEnemies[] = GameObject.FindObjectsWithTag("Enemy");

For (var enemy in allEnemies)
{

  var pos = enemy.transform.position ;


    var dist = Vector3.Distance(pos, transform.position);
    
    print ("Distance to Enemy: " + dist);
}

There might be other ways, though.

–
oxl

3

OK, thanks

The raycast is to check if the player can see the enemies(If they are behind walls, not include them)

But could you explain the code you are using ?

what is the For(var enemy in allEnemies)

4

Thats looping through the array , you get returned by

FindObjectsWithTag(“Enemy”) ;

Maybe a “For (Next)” loop is more comfortable for you ?

Which language you are using ?

–
oxl

5

I’m using javascript.
Ok, is For(Next) the same as For(var enemy in allEnemies) ?

I didn’t understand the var enemy in allEnemies …

6

“var enemy” is one single enemy entry in the Array of Enemies per loop .

Something like :

For (var count ; count < Enemies.Length ; count++)
{

    var enemy = Enemies[count];

    // var pos = enemy.transform.position;

     //check distance etc
}

–
oxl

7

the “for enemy in allEnemies” simply means:
for each GameObject (lets call it enemy so that we can refrence it), in the list of GameObjects (which is called allEnemies) do the following code: …

it’s just a short way for looping through all items in a list, and it comes in handy when you don’t know how many elements you have in your list

8

ok, thanks for the explanation

but how do we know that enemy is one element in the enemies array ? Because of the tag ?

9

no… it’s not because of the tag… enemy here is just a variable
we could have just used something like:

	for (var x: GameObject in allEnemies) { 
		var pos = x.transform.position ; 
		var dist = Vector3.Distance(pos, transform.position);
                //extra code
	}

what happens here is that for every item in the allEnemies list:
in the first loop, x = allEnemies[0]
in the second loop, x = allEnemies[1]
… etc

as i said, x (or enemy) has nothing to do with the tag, it’s just a variable that holds a different item of the list each time

10

Ok, I get it now. Thanks

11

OK, then I have all the help I need to make a basic AI script. Finally understand a lot more about scripting :smile:

Thank you guys

12

I tried the script but get the error (UnityException: You are not allowed to call this function when declaring a variable.
Move it to the line after without a variable declaration.) :frowning:

13

ok… i don’t know what you did, but here is how i’d write it:

function Update() {
	var nearestEnemy : GameObject = Nearest("Enemy");
	var nearestCar : GameObject = Nearest("Car");
}



function Nearest(searchTag : String) : GameObject { 
   var allObjs : GameObject[] = GameObject.FindGameObjectsWithTag(searchTag); 
   var shortestDist : float = Vector3.Distance(allObjs[0].transform.position, transform.position);
   var nearestObj : GameObject = allObjs[0];
   
   for (var obj : GameObject in allObjs) { 
      var pos = obj.transform.position ; 
      var dist = Vector3.Distance(pos, transform.position); 
       
      if (dist <= shortestDist) 
         nearestObj = obj;
   } 
    
   return nearestObj;
}

hope this would help :smile:

14

yeah that helped, but the error was in

var allEnemies = GameObject.FindGameObjectsWithTag("enemy");

I couldn’t do FindGameObjectsWithTag when declaring the variable

15

yeah… if you want a variable to be fileld depending on what is available in the world, then you must do that inside a function (i don’t know why lol)
so… if you still want to use a public (or exposed variable), then use something like this:

var allEnemies : GameObject[]
function Update() {
       allEnemies = GameObject.FindGameObjectsWithTag("enemy");
       //rest of code
}

i think this would make it work… not sure lol

16

yeah I realized that after checking around

I ended up with this code today,but still going to add more

var enemies : GameObject[];
enemies = GameObject.FindGameObjectsWithTag("enemy"); 

var minDistance = 100; 
var closest : Transform; 

var smooth = 0.5;

for (var enemy in enemies) 
{ 
   var dist = Vector3.Distance(transform.position, enemy.transform.position); 
    
   if(dist < minDistance) 
   { 
      closest = enemy.transform; 
      minDistance = dist; 
   } 
} 



function Update () {
	transform.position = Vector3.Lerp(transform.position, closest.position, Time.deltaTime*smooth);
}