Resolved Detecting collision before spawning/instantiating not working.

Have you looked at the docs for Physics2D.CircleCast ? For LayerMask (int) where each bit indicates a layer, you're passing default; the default of int is obviously zero (no bits on). It'll always return false if you ask it to not check any layers.

Whatever layers the Colliders the "itemPrefab" is on is what you should be using. Either that or check all layers using Physics2D.AllLayers. The value of this int is ~0 (all bits on).

NOTE: Your code here is "dangerous". If it ever gets to point where it cannot find anything then you'll lock the main-thread along with your game. It'll also take longer and longer as the area becomes populated.

 

I already did above! Did you read the part where I said try using "Physics2D.AllLayers" and that using "default" is wrong?

The Unity "default" layer has nothing to do with the C# "default" keyword. Trying not to turn this into a C# tutorial, default means use the default of the value. The value there is an int. The default of int is zero.

 

So this...

Code (CSharp):

1. if (!Physics2D.OverlapCircle(spawnPoint, ItemCollisionCheckRadius, Physics2D.AllLayers))

... or just don't specify that argument at all and just pass point and radius and it'll work or as I said, the layer that your prefab is on. Just don't use "default" because that's not appropriate there and is nothing related to the Unity default layer.

 

I presume you don't mean "crash" as in you get a crash report but instead it enters an infinite loop and locks the main thread as I stated above would happen if it cannot find a place to put your prefab.

Using that argument won't crash anything. It'll be because it's always hitting something and so it never exits your loop as I mentioned before.

You should debug it.

 

Also, that fact that you tried passing zero means you have a misunderstanding of what layers and layer masks are so I would highly suggest you find a tutorial on that before you proceed. Using stuff you simply don't understand is going to be painful. Guess coding is hard work!

Search for "using unity layer masks" on YouTube. There's hundreds of videos about it. With that knowledge, you'll figure this out.

 

No inconvenience at all and no need to be sorry! There's nothing wrong with not understanding but sometimes you just have to point out that the best course of action is to go learn a specific thing.

In the meantime, I'd try this which limits how many times it'll try:

Code (CSharp):

1. public float ItemSpawnRadius = 1.5f;
2. public float ItemCollisionCheckRadius = 0.5f;
3.  
4. const int RetryThreshold = 10;
5.  
6. public void SpawnItem()
7. {
8.     for(var n = 0; n < RetryThreshold; ++n)
9.     {
10.         Vector2 spawnPoint = (Vector2)_playerTransform.position + Random.insideUnitCircle.normalized * ItemSpawnRadius;
11.  
12.         if (!Physics2D.OverlapCircle(spawnPoint, ItemCollisionCheckRadius, Physics2D.AllLayers))
13.         {
14.             Instantiate (itemPrefab, spawnPoint, Quaternion.identity);
15.             Debug.Log("Spawned");
16.             return;
17.         }
18.     }
19.  
20.     Debug.Log("Could not find a place to spawn.");
21. }
22.  

 

I thought I'd post this separately but "ItemSpawnRadius" is very, very tiny. It's only 1.5 so a very small area. You're checking for things that are 0.5 in size. You'll only get a few of those at best in that area. Surely it should be a lot larger than that!

You can visualise this by adding this to your class which will draw a sphere at the player position with your spawn radius:

Code (CSharp):

1. public float ItemSpawnRadius = 1.5f;
2. public float ItemCollisionCheckRadius = 0.5f;
3.  
4. const int RetryThreshold = 10;
5.  
6. // Draw the spawn area.
7. private void OnDrawGizmos()
8. {
9.     Gizmos.color = Color.red;
10.     Gizmos.DrawSphere(_playerTransform.position, ItemSpawnRadius);
11. }
12.  
13. public void SpawnItem()
14. {
15.     for(var n = 0; n < RetryThreshold; ++n)
16.     {
17.         Vector2 spawnPoint = (Vector2)_playerTransform.position + Random.insideUnitCircle.normalized * ItemSpawnRadius;
18.  
19.         if (!Physics2D.OverlapCircle(spawnPoint, ItemCollisionCheckRadius, Physics2D.AllLayers))
20.         {
21.             Instantiate (itemPrefab, spawnPoint, Quaternion.identity);
22.             Debug.Log("Spawned");
23.             return;
24.         }
25.     }
26.  
27.     Debug.Log("Could not find a place to spawn.");
28. }

Also, you can get 2D physics to always draw the gizmos of any colliders you create by going into "Project Settings > Physics 2D > Gizmos" and check "Always Show Colliders". This means you don't have to select them for them to be drawn. This can help you understand what's in your scene.

Hope this helps.

 

Always feel free to ask!

Good luck with it.