# TOPDOWN_LAYER

Source: https://ref.dm-lang.org/notes/TOPDOWN_LAYER

TOPDOWN_LAYER is a special high value that can be added to the regular layer of any atom. This is only available when using a non-topdown world.map_format, such as isometric mapping.

The purpose of this value is to make an atom appear as if it belongs in a top-down map, when using a map_format other than TOPDOWN_MAP or TILED_ICON_MAP. This can be handy for title screens, or for special battle maps or the inside of a building in an RPG.

When using this special layer, it should be added to the layer an atom normally uses. For instance a turf should have a layer of TOPDOWN_LAYER + TURF_LAYER. Usually you will want one part of the map to have TOPDOWN_LAYER, and for players to be unable to walk to there from the regular map. Mixing topdown icons and icons in the normal map_format in view of each other could look very strange. For safety's sake, the easiest thing to do is to keep them on separate z layers.

This can be mixed with EFFECTS_LAYER. Anything in TOPDOWN_LAYER will display on top of EFFECTS_LAYER, and TOPDOWN_LAYER + EFFECTS_LAYER will be above both.

This can also be mixed with BACKGROUND_LAYER, which takes priority over everything else.

Images or overlays with FLOAT_LAYER can be left alone. They will automatically have the same layer as whatever atom they are attached to.

### See also
- [layer var (atom)](https://ref.dm-lang.org/atom/var/layer.md)
- [map_format var (world)](https://ref.dm-lang.org/world/var/map_format.md)
- [BACKGROUND_LAYER](https://ref.dm-lang.org/notes/BACKGROUND_LAYER.md)
- [EFFECTS_LAYER](https://ref.dm-lang.org/notes/EFFECTS_LAYER.md)
- [stddef.dm file](https://ref.dm-lang.org/appendix/stddefdotdm.md)