check if gameobjects overlap when collision occurs help?

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Hi everyone. Can someone help me with a JavaScript sample of how to check if one Game object prefab overlaps another At the point that a collision occurs?

Eg. Gameobject A,B, and C are overlapping each other in a 2d scene, and then game object D is moved in the direction and collides with game object A w$$anonymous$$le it overlaps with B and C. Game object A,B, and C are all destroyed and a special effects prefab is instantiated at the point/position of the collision. Can anyone help me with coding t$$anonymous$$s pseudo script concept?

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Answer by CScherer549 · Jul 20, 2014 at 05:57 PM

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Is t$$anonymous$$s what you mean? What collision are you wanting to look for? You want an object and anyt$$anonymous$$ng it's overlapping to be destroyed on collision? You Also say 'point', do you mean the point in space the collision happens or the point in time?

if that's so I would try somet$$anonymous$$ng like t$$anonymous$$s.

 //first add a OnCollisionEnter method to the script attached to the object you want to check for collisions. That will notify you when it collides with somet$$anonymous$$ng and what it $$anonymous$$t. I would write a seperate script/method that checks for whether your object is overlapping stuff.
 
 function OnCollisionEnter2D(Collision col){
        if(the object you collided with has a certain tag e.g. "projectile"){
           do stuff then check for t$$anonymous$$ngs the struck object overlaps      
           checkForOverlap(col.gameObject);
        }
        //i would do it that way so you can use colliders to detect overlap and also for the initial collision
 }
 
 GameObject[] : function checkForOverlap(GameObject){
      //In here you could find all the objects the initial object is overlapping also using colliders. In t$$anonymous$$s case I would probably 
 }

Let me know if you want clarification or if t$$anonymous$$s helps at all!

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mealone · Jul 20, 2014 at 10:52 PM 0

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thank you so much for your response. Is your code in C++? Could you clarify a bit, or try javascript? I am not very versed on c++ just as yet. Thanks in advance.

CScherer549 · Jul 22, 2014 at 05:28 AM 0

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It should be javascript. Something like this

 import UnityEditor;
 import System.Collections.Generic;
 
 //This would hold all the objects overlapping with the one this script is attached to
 var overlapping : ArrayList
 // Use this for initialization
 function Start () {
 }
 
 // Update is called once per frame
 function Update () {
 }
 
 //This is refering to the inital collision between two objects, a projectile and a player or environment object for example.
 function OnCollisionEnter2D(col: Collision2D){
 //Here you would probably want to check what you hit, you don't want the same actions happening to everything you shoot. 
 //Walls wouldn't explode when you shot them for example
        if(the object you collided with has a certain tag e.g. "projectile"){
        
           do stuff then check for things the struck object overlaps      
           checkForOverlap(col.gameObject);
        }
        //i would do it that way so you can use colliders to detect overlap and also for the initial collision
 }
 
 function OnCollisionStay2D(col: Collision2D){
     //This method checks all objects that remain collided with the object the script is attached to.
     //Anything inside this object is added to the list, you should look into making sure the object being added
     //is unique and add it only if it is
     overlapping.Add(col.gameObject)
 }
 
 function OnCollisionExit2D(col: Collision2D){
 //When an object stops colliding it is no longer overlapped, so we remove it from the list
     overlapping.Remove(col.gameObject)
 }

Let me know if there's something you don't understand, I'd be glad to clarify.

mealone · Jul 22, 2014 at 12:31 PM 0

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Thanks for your response again. I got this error message ---> Unknown identifier: 'checkForOverlap'. I can't seem to find it in the reference as well. Is this the code which checks the overlaps? and the ref guide suggests overlapcircleall... what do you think?

CScherer549 · Jul 22, 2014 at 05:42 PM 0

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That checkForOverlap line was meant to be a pseudocode suggestion. Yeah, overlapCircleAll looks great, or if your object isn't round you could use OverlapAreaAll.

check if gameobjects overlap when collision occurs help?

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