Question How to check for the closest game object to player

I was wondering if there is an efficient method to find the closest object to the player from the scene in unity during runtime. I am hoping to run a function only when the player character is at a certain distance from the closest game object. (2d game)

 

Assuming your player has a rigidbody component, make a child GameObject of your player and attach a trigger collider to it. Then attach a script to the player that listens for OnTriggerEnter.

 

Thanks a lot PraetorBlue.

 

Why do you need to know the closest GameObject? OnTriggerEnter will tell you which object has entered the trigger zone.

 

Assuming you have a collection of GameObjects within a certain radius from the player:

Code (CSharp):

1. GameObject[] nearbyObjects;

You can get the distance of each one from your player by looping through and subtracting their positions from your player's position, then using the value of the returned

sqrMagnitude

. Keep a cached variable of the current closest distance while looping through the GameObjects and update it if the next object's distance is smaller than the cached variable.
Something like this:

Code (CSharp):

1. GameObject GetNearestObject(GameObject sourceObject, GameObject[] nearbyObjects) {
2.    GameObject nearestObject = null;
3.    float nearestDistance = float.MaxValue;
4.  
5.    for(int i = 0; i < nearbyObjects.Length; i++) {
6.       float distance = (nearbyObjects[i].transform.position - sourceObject.transform.position).sqrMagnitude;
7.  
8.       if(distance < nearestDistance) {
9.          nearestObject = nearbyObjects[i];
10.          nearestDistance = distance;
11.       }
12.    }
13.  
14.    return nearestObject;
15. }

How you get the collection of nearby GameObjects is up to you. You can use the trigger collider method above, or a physics overlap-sphere call, or have a preset cached array of objects to compare, etc.

 

I want my player to enter a gravitational field of another GameObject only when it is at a fixed distance from the player. The trigger collider might work well for this I think. I am looking to find the closest GameObject and assign that specific game object to a script.