Instantiate 4 prefabs at 4 locations, shuffled, Unity Engine C#

Question

What I have are 4 platforms that I instantiate at 4 locations. What I want is for the platforms to be shuffled every time. My code so far:

using UnityEngine;

public class PlatformCreator : MonoBehaviour {

 public GameObject[] platforms;
 public Transform[] points;

 private void Start()
 {

     for (int i = 0; i < points.Length; i++)
     {
         Instantiate(platforms[i], points[i].position, Quaternion.identity);
     }
 }

}

For example the platforms now always spawn in the same order - pink, yellow, blue, purple

I want them to be spawned in different order every time, for example - yellow, blue, purple, pink. I've tried creating an int index with random.range, but I am messing something up

Could you use int x = Random.Range(0,points.Length) inside your for loop and then points[x].position? — apollosoftware.org, Dec 20 '17 at 20:28

Brandon Miller · Accepted Answer · 2017-12-20T18:34:27.030

4

You could add the points to a List instead of an array, which will help you to "shuffle" the values. Taking the shuffle function from This SO post, you could do something like this:

public class PlatformCreator : MonoBehaviour {

 public GameObject[] platforms;
 public List<Transform> points;

 private Random rng; 

 public void Shuffle<T>(this IList<T> list)  
 {  
    int n = list.Count;  
    while (n > 1) {  
    n--;  
    int k = rng.Next(n + 1);  
    T value = list[k];  
    list[k] = list[n];  
    list[n] = value;  
    }  
 }

 private void Start()
 {
    rng = new Random(); 
    points.Shuffle();
    for (int i = 0; i < points.Count; i++)
    {
        Instantiate(platforms[i], points[i].position, Quaternion.identity);
    }
 }
}

edited Dec 20 '17 at 18:34

answered Dec 20 '17 at 18:23

Brandon Miller

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Unfortunately it does not work, because points.Length property can't be used with lists. Perhaps I can try with .Count (points.Count)? Same problem with int k = rng.Next(), I am unable to use Next(), receiving an error. – Lee Jaedong Dec 20 '17 at 18:31
Yes, sorry. List uses Count, not Length. Updated answer. – Brandon Miller Dec 20 '17 at 18:34
Could you tell me what the error is? I have no way of knowing unless you post it. – Brandon Miller Dec 20 '17 at 18:37
it works, I guess i'll look around more on this shuffling method, it caught my attention. Thanks – Lee Jaedong Dec 20 '17 at 20:28

Instantiate 4 prefabs at 4 locations, shuffled, Unity Engine C#

1 Answers1