Format
Enter(atom/movable/O, atom/oldloc)
Returns
1 to permit; 0 to deny.
When
Called when an object attempts to enter the contents list.
Args
O: the object attempting to enter.oldloc: the old (current) loc of the object attempting to enter.
Default action
Explained below.
Areas, objs, and mobs will always permit anything to enter by default.
Note
The following behavior only applies to LEGACY_MOVEMENT_MODE. In all other movement modes, the turf’s contents are not taken into account. Only the result of turf.Cross() matters.
Turfs will return 1 (permit) or 0 (deny) based on density. In simple terms, if the atom that is entering is dense, then the turf will deny entry if the turf itself or its contents (any that take up the full tile) are dense.
What actually happens in turf.Enter() is more detailed: Cross() is called for the turf, and if it succeeds (movement is permitted), then Cross() is called for any atoms in turf.contents that cover the entire tile. If any Cross() call fails, Enter() fails too and will return 0.
If a mob is standing on a turf but its bounding box does not cover the whole tile, it is ignored by Enter(). Instead, its Cross() proc is called if there is a danger of the object overlapping it.