Spawn List of game Objects

Question

I am trying to spawn a list of GameObjects. I have been roaming the documentation and I have tried to do this:

Currently I am getting out of bounds argument. Could anyone point me in the right direction? Thanks in advance.

      public void spawntiles()
 {
     for (int i = 0; i < int_tile_spawnrate; i++)
     {
         int f = i - 1;
         Vector2 previous_tile_location;
         if (i == 0)
         {
             previous_tile_location = screenPosition;

             array_tiles.Add(Instantiate(Tiles, previous_tile_location, Quaternion.identity) as GameObject);

         }
         else
         {
             previous_tile_location = array_tiles[f].transform.position + array_tiles[f].GetComponent<Collider>().bounds.size;
             // var vector_previous_tile_position =array_tiles[f].transform.position;
             // vector_previous_tile_position.x = vector_previous_tile_position + Tiles.GetComponent<Collider>().bounds.size;
         }
        




     }
 }

Answer 1

Best Answer

Answer by Anton-Korhonen · Oct 31, 2016 at 10:10 PM

I would first store the reference to previous_tile_location outside the loop. Then inside your for-loop i would first spawn your Tiles object and then assign the previous_tile_location. This way every time the for-loop iterates, the object is instantiated to the location set in the last loop.

Something like this (untested):

     previous_tile_location = screenPosition;

     for (int i = 0; i < tile_spawnrate; i++)
     {
         array_tiles.Add(Instantiate(Tiles, previous_tile_location, Quaternion.identity) as GameObject);
         previous_tile_location = array_tiles[i].transform.position + array_tiles[i].GetComponent<Collider>().bounds.size;
     }

And if you want append the width of your collider to the position, you could use something like:

 previous_tile_location = array_tiles[i].transform.position + new Vector3(array_tiles[i].transform.position.x + array_tiles[i].GetComponent<Collider>().bounds.size.x, array_tiles[i].transform.position.y, array_tiles[i].transform.position.z));

Oh that horrible forum code formatting.

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upariver · Nov 01, 2016 at 01:01 PM 0

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Thank you very much!

Answer 2

Answer by EpicPants · Oct 31, 2016 at 10:58 AM

You don't add to your array in the else statement (where i!=0) so when i ==2 f will be 1 but your array count will be just 1. Basically you only add to your array when i == 0.

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upariver · Oct 31, 2016 at 11:02 AM 0

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That is one of the issues, thanks for helping out. However, I get nothing spawned on the screen at all either. Could you tell me why?

EpicPants upariver · Oct 31, 2016 at 11:20 AM 1

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Do they appear in the hierarchy? If so it may be an issue with positioning or scaling. I can't see any problems with your code at a glance but i'm not in a position to test it.

upariver EpicPants · Oct 31, 2016 at 01:51 PM 0

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Thank you for reminding me of the hierarchy. It was spawning, but it was spawning away from the screen.

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upariver · Oct 31, 2016 at 02:57 PM 0

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Sorry to bother, but how would you get the width of the previous gameobject in the list?

Answer 3

Answer by bishop87 · Oct 31, 2016 at 03:16 PM

try changing to i < int_tile_spawnrate to i < int_tile_spawnrate.length

Remove int f = i-1 and everyhwere that you have f on line 16/17 replace it with i.

also change if (i == 0) to if (i = 0)

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upariver · Oct 31, 2016 at 05:43 PM 0

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Thank you for answering. The thing is that I need to get the previous gameobject on the list's position and add it's length in order to spawn the next object in front of it.

JincSoft upariver · Nov 01, 2016 at 06:45 AM 1

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Well the part of the int f=i-1 will cause an out of bounds exception because the first time it loops it will be equal to -1 (arrays start at 0).

@bishop87 this is C# so if (i == 0) is correct, if(i=0) will throw an error because you are trying to assign 0 to i ins$$anonymous$$d of comparing the value.

bishop87 JincSoft · Nov 01, 2016 at 07:03 AM 0

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@JincSoft Ah yes you're right. I sometimes get confused about which is a value comparison and which one is a bool comparison in IF statements

Spawn List of game Objects

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