Spawning Sprites on Certain Tiles

Unity Engine
1

I am working on a top-down 2D lawnmowing game, and I want to spawn blades of grass on the level. I am using tilemaps to design levels and I am hoping to be able to place a green tile, and have grass blade sprites spawn randomly across those tiles when the level starts, but not across tiles that are sidewalks or roads. I have worked out how to spawn the sprites, but I have gotten stuck on trying to get information from the tilemap. Can anyone recommend a way to detect certain tiles in a tilemap (or any active tile in a grass specific tilemap), and have that communicate with a grass spawning script?

2

I think what you’re looking for is this:

https://docs.unity3d.com/Manual/Tilemap-ScriptableTiles.html

Caveat: I’ve not tinkered much with them but it seems they could (with perhaps additional scripting) do exactly what you want as far as special behavior in special parts of your map.

3

Approach 1: Using Scripting API to write additional tiles for the grass blades on top of grass tiles.

public class GrassSpawner : MonoBehaviour
{
    // connect these properties up in the Inspector
    public Tilemap grassTilemap;  // green tiles
    public Tilemap grassTuftTilemap;  // grass blades, needs to have order so that render on top of grassTilemap
    public TileBase grassTile;
    public TileBase grassTuft;
 
   void Start()
   {
       SpawnGrassTufts();
   }

    void SpawnGrassTufts()
    {
            foreach (var cell in grassTilemap.cellBounds.allPositionsWithin)
            {
                if (tilemap.GetTile(cell) == grassTile && Random.value < .33f)
                {
                    // 1/3 of grass tiles will receive grass tuft on top
                    grassTuftTilemap.SetTile(cell, grassTuft);
                }
            }
    }
}

Approach 2: use RandomTile

Another way to do this would be to create a RandomTile. See 2D Tilemap Extras package, available in the Package Manager. You would have the sprite sometimes be plain green. Other times, you’d use a different sprite: green plus blades.