Virtual directory mapping
Version 1.9.0 introduces virtual directory mappings (abbrev. VDM), which allow you to make the contents of one directory appear inside another directory at runtime. For example, you could have a directory called MyAuto with a set of data files somewhere on your hard drive. You could map this directory to Data/<Game>/Auto, which would cause MyAuto to behave as though it was an auto-loading directory.
A virtual directory mapping is defined using the -vdmap option. It takes the source and destination directories as parameters. For example:
-vdmap "D:\Games\MyAuto" "C:\Doomsday\Data\jDoom\Auto"
You can define an unlimited number of virtual directory mappings using multiple -vdmap options.
Note, however, that -vdmap only affects real files. It does not affect virtual files in PK3s or anywhere else. The virtual directory mappings are tried when all other methods of finding a file have failed. So, all real files and virtual files override the VDMs.