Collision detection (2d) with clone

Hello,

I struggle a few days now with this problem. In my Player script, the sphere gets instatiatet everytime I press the spacebar. This works pretty good.
And now, when I shoot another one, I want to check the collision between them. They have both a property called "sphereVal" and the value is random.
The problem now is, when they collide, both of them trigger the OnCollisionEnter2D.

Lets say the first sphere fired has the value 10 and the other one 20. When 10 hits 20 it Outputs "less" and "greater" at the same time because they "looking for each other".

I think ist because they have the same GameTag but I have no clue how to deal with that.

My goal is, when I shoot a sphere, it should only trigger the collision from "one perspective", if that makes sense.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class sphere: MonoBehaviour {
6.     public Rigidbody2D rb;
7.     public int speed;
8.     public int sphereVal;
9.     // Use this for initialization
10.     void Start () {
11.         rb = GetComponent<Rigidbody2D>();
12.         rb.tag = "sphere";
13.         kugelZahl = Random.Range(1,100);
14.         speed = 6;
15.        
16.     }
17.    
18.     // Update is called once per frame
19.     void Update () {
20.             float moveVertical = Input.GetAxisRaw("Vertical");
21.             Vector3 toTop = new Vector3(0, moveVertical + 0.5f, 0.0f);
22.             rb.velocity = toTop * speed;
23.     }
24.  
25.     private void OnCollisionEnter2D(Collision2D collision)
26.     {
27.        
28.         if (collision.gameObject.tag == "sphere" || collision.gameObject.tag == "background")
29.         {
30.            
31.            
32.             rb.constraints = RigidbodyConstraints2D.FreezePositionY | RigidbodyConstraints2D.FreezePositionX;
33.             int a = collision.gameObject.GetComponent<kugel>().kugelZahl;
34.            
35.             if(sphereVal< collision.gameObject.GetComponent<kugel>().sphereVal)
36.             {
37.                
38.                 Debug.Log("less");
39.             }
40.             if (sphereVal> collision.gameObject.GetComponent<sphere>().sphereVal)
41.             {
42.                 Debug.Log("greater");
43.             }
44.  
45.         }
46.     }
47. }

Greetings from Germany! (Yep, this explains my english)

 

Hi,

Your English is more than good enough.

Even with unique tags both OnCollisionEnter2D handlers will fire.

If you must have all spheres listening and you want to keep all your "sphere" scripts simple and symmetrical then you could tackle this by making a simple global collision manager; a simple singleton class (only one instance of this class exists for whole game):

That singleton should receives a call like:

Code (CSharp):

1. AddCollision(Collision2D collision)

So it will still be called twice for each collision between 2 objects.

But that manager can make decisions based on filters:

The manager maintains a short cyclic buffer of previous collisions and their times.

The manager only acts once on collisions <K distance apart.

The manager only acts once on collisions <T time apart.

The manager can also make higher level logic decisions (i.e. higher balls kill lower balls etc).

You may want to pass more info into the manager like:

Code (CSharp):

1. AddCollision(Collision2D collision, sphere cSphere)

Then the manager can also read any public data in cSphere/s for advanced decision making.