Spawn an object to a random spawn point from a list

Question

I want to spawn 3 of the same game object at a random spawn point that I put into a list. But everytime I run my project there's an error saying ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index

I was wandering how does t$$anonymous$$s error is happening, or there can be a better way to do what i am trying to implement?

 private void Start()
 {
     foreach (GameObject obj in GameObject.FindGameObjectsWithTag("Savee"))
     {
         saveePoints.Add(obj);
     }
     spawn();
 }

 void spawn()
 {
     for (int i = 0; i <= 2; i++)
     {
         i = Random.Range(0, saveePoints.Count);
         saveePoints[i] = Instantiate(saveeObject, saveePoints[i].transform.position, transform.rotation) as GameObject;
     }
 }

Answer 1

Answer by Metais · Jun 04, 2019 at 01:57 PM

You are changing the value of i inside your for loop, w$$anonymous$$ch you are already using to cycle through it three times. Change the i to j or similar, perhaps that helps?

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Answer 2

Answer by SirPaddow · Jun 04, 2019 at 02:03 PM

You shouldn't use i to count your instances and to get a random spawn position. Try somet$$anonymous$$ng like t$$anonymous$$s.

  void spawn()
  {
      for (int i = 0; i <= 2; i++)
      {
          int spawnIndex = Random.Range(0, saveePoints.Count);
          Instantiate(saveeObject, saveePoints[spawnIndex].transform.position, transform.rotation);
      }
  }

If the error is still showing after, make sure your Start function actually finds the spawn positions.

Also, I don't understand why you replace your spawn positions with your new instances... Can you tell what you are trying to do exactly?

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munggol97 · Jun 04, 2019 at 02:31 PM 0

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Thanks for your feedback I still got the error but as you say my start function is not founding my spawn points I noticed it by puting a Debug.Log inside the foreach loop. What should I do? Maybe it is because my spawn points were also instantiated when the game starts.

Metais munggol97 · Jun 04, 2019 at 02:56 PM 0

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You could try to instantiate the list of save points as a new, empty list before adding new objects to it, that way you are certain of the size of the list and can understand your indexoutofbounds exception better.

Like this:

  private void Start()
  {
      saveePoints = new List<GameObject>();
      foreach (GameObject obj in GameObject.FindGameObjectsWithTag("Savee"))
      {
          saveePoints.Add(obj);
      }
      spawn();
  }

SirPaddow munggol97 · Jun 04, 2019 at 04:05 PM 0

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Does your scene actually contain gameobjects with the tag "Savee"? I can't see why the find function would fail, but you can try to avoid it by assigning your spawn positions through the inspector by making "saveePoints" public.

Spawn an object to a random spawn point from a list

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