[Beginner question] 2D Time based spawning of objects like weeds or stones/ore

Question

Hi there,

I'm currently working on a topdown 2D game and have a question about spawning stuff like Weeds or rocks after a certain amount of time.

What I'm trying to achieve:

Similar to games like Stardew Valley and Forager, I am trying to make a spawner that spawns weeds, rocks, or even trees that the player can interact with (chop them or gather them etc).
This would need a timer, and something that checks if the area is empty.

Where I am lost:

So right now I have my tilemap, which is the background. I then want to spawn trees, weeds, and other objects at random which I can cut or collect.

I am just unsure if I need to make a separate grid for this, that checks if the cell is empty, and if it is, it can spawn an item at random. Or, if somehow I should just do this without a grid?

I'm also a little confused as to how I achieve this the best and what the best practice is for this.

Below is a video, with a timestamp. At the timestamp, you see a bunch of ores that randomly spawned. I'm trying to create something similar. As far as I can tell, the spawner checks if the area is empty (on a grid?) and then it spawns say 1 object on a random cell that is empty every 1 minute or so.

Video is here

Anyone got any idea on how to do this?

I did this but I don't think it's right...

     public int numberToSpawn;
     public List<GameObject> spawnPool;
 
     public void SpawnObjects()
     {
         for (int i = 0; i < 10; i++)
         {
             float spawnY = Random.Range
                 (Camera.main.ScreenToWorldPoint(new Vector2(0, 0)).y, Camera.main.ScreenToWorldPoint(new Vector2(0, Screen.height)).y);
             float spawnX = Random.Range
                 (Camera.main.ScreenToWorldPoint(new Vector2(0, 0)).x, Camera.main.ScreenToWorldPoint(new Vector2(Screen.width, 0)).x);
 
             Vector2 spawnPosition = new Vector2(spawnX, spawnY);
             Instantiate(spawnPool, spawnPosition, Quaternion.identity);
         }
     }

Answer 1

I'm also creating a 2d open-world farming game that is somewhat similar to forager...

The way I did i handled spawning of objects : I made my world randomly generated tiles that are simple gameobjects. Then I actually instatintiated the objects as children of the tile... So when I need to check whether the tile is full or not I just check the childCount of the object

BUT, I think you are using a tilemap to make your world.
A possible solution is to this is set up a timer and use raycasts to check whether an object is present in the given position... If you need code for reference on how to do it, I can provide some :)

Reference code :

 [SerializeField] private int MaxX, MaxY, MinX, MinY; //Assign all these in the inspector according to the size of the tilemap
 
 [SerializeField] private GameObject[] SpawnObjs; //These are the objects like weeds, stones, etc...
 
 private float Timer;
 [SerializeField] private float MaxTime; //This is the time between spawns, change accordingly
 
 private void Update()
 {
     Timer += Time.deltaTime;
     if (Timer >= MaxTime)
     {
         int XPos = Random.Range(MinX, MaxX + 1);
         int YPos = Random.Range(MinY, MaxY + 1);
 
         int InstNum = Random.Range(0, SpawnObjs.Length);
 
         Instantiate(SpawnObjs[InstNum], new Vector3(XPos, YPos, 0f), Quaternion.identity);
 
         Timer = 0;
     }
 }

This isn't tested but i think it should work :)

Reference code 2 : Change the code to this if you want to be sure that no objects spawn on top of each other

  [SerializeField] private int MaxX, MaxY, MinX, MinY; //Assign all these in the inspector according to the size of the tilemap
     
     [SerializeField] private GameObject[] SpawnObjs; //These are the objects like weeds, stones, etc...
     
     private float Timer;
     [SerializeField] private float MaxTime; //This is the time between spawns, change accordingly
     
     private void Update()
     {
         Timer += Time.deltaTime;
         if (Timer >= MaxTime)
         {
             int XPos = Random.Range(MinX, MaxX + 1);
             int YPos = Random.Range(MinY, MaxY + 1);
     
             int InstNum = Random.Range(0, SpawnObjs.Length);
             
             RaycastHit2D = hit;
             if (Physics2D.Raycast(new Vector3(XPos, YPos, 1f), Vector3.back, out hit))
             {
                 if (hit.tranform.tag != "InstObj")
                 { 
                    Instantiate(SpawnObjs[InstNum], new Vector3(XPos, YPos, 0f), Quaternion.identity);
                 }
             } 
             Timer = 0;
         }
     }

Important : All the Objects like weeds, stones and whatever you are instantiating must have the tag InstObj

Sorry for not posting this code sooner, i got caught up in some other work... Good Luck :)

[Beginner question] 2D Time based spawning of objects like weeds or stones/ore

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