Merging two tilemap grids into one with script

I have a base tilemap grid prefab that I'm loading as a gameobject. The grid has two tilemaps separately; one for the floor, one for the walls. This first prefab is randomly generated in a chunk-by-chunk basis, and has a variable size. I also have a separately created tilemap grid prefab that I hand-created. It is the same size as the chunks that make up the first grid. I'd like to be able to merge the two prefabs into one so that the second prefab overwrites one of the chunks of the first prefab.

I'm able to load the prefabs as gameobjects via script, but I'm not sure how to iterate through the tile coordinates in order to replace the tiles that I want. I can't seem to find a method that allows me to iterate through the tilemap coordinates.

If someone knows a way to get the size of the tilemap grid, I could then use my existing method of creating tiles and simply create a new grid with the tiles copied from the prefabs. I also need to know what method I need to use to do this for both the floor tilemap and the walls tilemap, so I need to know how to diferentiate between the two when reading the gameobject data.

 

https://docs.unity3d.com/ScriptReference/Tilemaps.Tilemap.html

Get bounds in cell-space. Note, unless it's completely full of tiles then many tiles will be null
https://docs.unity3d.com/ScriptReference/Tilemaps.Tilemap-cellBounds.html

BoundsInt has convenient way to foreach through all of its contents: boundsInt.allPositionsWithin
https://docs.unity3d.com/ScriptReference/BoundsInt-allPositionsWithin.html

So you can loop through your sourceTilemap (walls), use GetTile and if not null apply to the targetTilemap (floor) with SetTile. If performance matters here and you're processing a large # tiles, then it may be more efficient to use GetTileBlock and SetTiles after pruning away the nulls b/c it sounds like you wouldn't want to clear your target where your source has a null tile.

 

That's actually pretty great. I'll definitely use that, and I can probably make a workaround for null tiles like you said.

I have the grid as the prefab though, so I assume I'll want to use GameObject.GetComponentsInChildren to read the data for the two separate tilemaps I have on the grid?
https://docs.unity3d.com/ScriptReference/GameObject.GetComponentsInChildren.html

 

Yeah, that will give you the tilemaps in order. Then it's a matter of treating the correct one as the source and the other as the target.

edit: I should note that if your two tilemaps aren't using the same bounds, then perhaps your copy may need to add some Vector3Int offset so that when you copy from one it'll put the tiles into the correct position of the other. That will normalize the positions to the coordinates you want your tiles confined within.