Instantiate 4 prefabs at 4 locations, shuffled

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.

Answer 1

Best Answer

Answer by Larry-Dietz · Dec 20, 2017 at 06:28 PM

Try something like this...

 public void Shuffle()
     {
         GameObject tmp;
 
         for (int i = 0; i < 100; i++)
         {
             int a = Random.Range(0, platforms.Length);
             int b = Random.Range(0, platforms.Length);
             
             tmp = platforms[a];
             platforms[a] = platforms[b];
             platforms[b] = tmp;
         }
     }

Then add a call to Shuffle in start before your loop.

I haven't tested this. I normally use List instead of an array, and i know this method will work with a list. I just modified it for an array off the top of my head. If it doesn't work, let me know.

I'm always ending up with off by 1 errors, so if you get an index out of bounds error, change the .Length lines in the Random.Range to .Length - 1

Hope this helps, -Larry

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fredkoto · Dec 20, 2017 at 07:27 PM 0

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I don't $$anonymous$$d using a list ins$$anonymous$$d of an array. How would go about creating this with a List, ins$$anonymous$$d of an Array?

Larry-Dietz fredkoto · Dec 20, 2017 at 07:37 PM 0

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Either way is fine.. But if you want to use a list, change your declaration to public List platforms = new List();

then in the Shuffle routine, change the .Length to .Count

Let me know if you have any problems with this. -Larry

fredkoto Larry-Dietz · Dec 20, 2017 at 08:29 PM 0

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It actually works both with Lists and Arrays! it's a great method, would you please explain how this exactly works? I'm having a hard time understanding it. Thanks!

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Instantiate 4 prefabs at 4 locations, shuffled

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