Tilemap: Resizebounds() And Clearalltiles() Leaving Orphaned Tile Resources

So I have created an endless terrain generator using an isometric tilemap. Rather than implementing a chunking system I am actually updating the tilemap every time the player moves to a new tile. Basically it looks something like:

Code (CSharp):

1. Start() {
2.      Tilemap.size= new Vector3Int(xSize, ySize, 1)
3. }
4. FixedUpdate() {
5.      if(currentCell != previousCell)
6.      {
7.          Tilemap.origin = player's new location;
8.          Tilemap.ResizeBounds();
9.          Tilemap.CompressBounds();
10.          RecalculateTiles();
11.     }
12. }

This actually works exactly like I want it to and performs quite well... sorta.

According to the documentation: "Tiles outside of the bounds will be removed from the Tilemap," and this works as expected. It may be that I don't have a complete understanding of the feature, but it seems like if the tiles are removed that they should also be destroyed. However, the tiles remain in the scene with 0 reference counts and just continue to eat more and more memory.



After searching the forums a bit I learned that these are not managed objects and therefore not subject to GC.

https://forum.unity.com/threads/mem...-gc-ed-when-re-allocated.513961/#post-3365665

"The rule-of-thumb is that if the type inherits from UnityEngine.Object, it lives in C++, and you're handling a representation of it in your C# scripts."

Now my fix for this is as follows:

Code (CSharp):

1.      TileBase[] originalTiles = tilemap.GetTilesBlock(tilemap.cellBounds);
2.      tilemap.origin = origin;
3.      tilemap.size = size;
4.      tilemap.ResizeBounds();
5.      tilemap.CompressBounds();
6.      TileBase[] newTiles = tilemap.GetTilesBlock(tilemap.cellBounds);
7.      TileBase[] removedTiles = originalTiles.Except<TileBase>(newTiles).ToArray();
8.      removedTiles.ToList<TileBase>().ForEach(t => Destroy(t));

I'm OK with this, but is there any reason why ResizeBounds() couldn't handle this? Also, ClearAllTiles() behaves the same way.

Edit: I should point out that if all my above assumptions are correct, I would only expect these methods to clean up unreferenced objects (e.g. I may be storing Tiles in a collection for the purpose of re-usability.)

Cheers

 

I wasn't really sure if this was a bug or if the feature was working as intended so I started by soliciting some feedback first.

I went ahead and submitted a bug. The case# is 1146884.

Cheers