Default value
Empty list.
Turfs, movable atoms, and images can be given a list of atoms (limited to turfs and movable atoms) that are attached to them visually, like an overlay or image object, but act independently and have their own identity. These are visual contents. The purpose of visual contents is to provide an alternative system to overlays and images, with a little more flexibility for various special effects.
For example, a mob with an obj in its visual contents will show the obj as if it’s following the mob around like an overlay, but clicking on the obj will not—unlike an overlay or an image object—count as a click on the mob. Likewise, the obj will retain its own separate mouse_opacity setting, which is not true of regular overlays.
An atom that appears on the map normally can still be in the visual contents of another atom. However it will not apply gliding and step offsets here. Also, considerations like visibility will not apply.
If a turf is in an atom’s visual contents, the turf and all of that turf’s contents will be displayed. (In the case of big atoms, or movable atoms with step offsets, only atoms that actually have that turf as their loc will appear. “Overhangers” will not.) Gliding and step offsets will be applied to that turf’s contents normally; but again visibility, opacity, etc. will not be considered. (If you have one or more turfs in visual contents, an object gliding to a new turf outside of that list will not be shown because it’s already technically on the new turf.)
If multiple turfs are present in visual contents, they will be offset as needed (relative to the southwest-most turf) to appear in the correct positions. That is, pixel_x and pixel_y offsets will be applied automatically, so if you add an entire block to visual contents (be aware this will impact performance), you don’t have to do anything else to make the block appear normal.
You can alter some aspects of how an object behaves when in visual contents by changing its vis_flags var. In particular this is useful if you want an object to behave more like an overlay, inheriting aspects of its parent object or even acting like a part of that object instead of an independent one. Also this can make an object act like an underlay instead of an overlay when using a floating layer.
Visual contents do not impact the results of view() or range(), or verb availability, in any way. This is strictly a visual effect.
Being in a visual contents list counts as a reference for anything in the list, the same way that being on the map or inside of a movable counts as a reference.