Mask routines are now ready, but they aren't possibly yet used. The routine checking for object creation is including a check for mask. Anyway, level creation works the usual way, but there is a strange bug which has to be fixed before doing anything else. It's creating a null tile at the top left corner of every level. To find out more what it is in first place I really need to write a debug routine to show the contents of a tile.
I wrote a new debug routine to collect "togglers" which have value of true or false. The scope of this project is so small, that there are only two togglers at the moment: FOV and mask map tile, which is a routine that shows the mask tile using a color data assigned to it. That way you can make sure the mask map is correctly created.
The null tile bug can be related to place searching. I could make that better to spot by adding a debug id (for example a piece of text) to each call. You can then spot which routine called the search for list of tiles.