Folder structure and RTTR_*DIR config variables
We want to support the following use cases for running RTTR:
- Run from extracted archive downloaded from the website
- Run from installed location via CMake (possibly modified by
DESTDIR) - Run from build directory (for testing/debugging)
- Run from installed package (especially linux)
- Allow moving around the installation dir (especially for windows, LAN parties etc)
For this a certain folder structure is used.
CMake defines some variables (except for windows) which are then transferred as defines to the program. These are, with usual defaults in parentheses:
-
RTTR_BINDIR(bin): executables -
RTTR_DATADIR(share/s25rttr): data for RTTR (language files, maps, resources) -
RTTR_GAMEDIR(RTTR_DATADIR/S2): original game files (DATA, GFX folders) -
RTTR_LIBDIR(lib): shared binaries -
RTTR_DRIVERDIR(RTTR_LIBDIR/driver): audio/video driver libs -
RTTR_DOCDIR(doc): documentation files
On windows most of them are basically "." so they are all in the same folder. On *Unix they are taken from GNUInstallDirs
Often all of them are relative to a path prefix which is usually the installation directory (e.g. CMAKE_INSTALL_PREFIX possibly with DESTDIR prefixed itself).
This prefix path can be found by removing RTTR_BINDIR from the the full path to the executable being run which usually suffices.
Optionally it is possible to overwrite this prefix path by setting the environment variable RTTR_PREFIX_DIR before starting the program.
Having found (or set) the prefix path, the program treats all directories (RTTR_*DIR) with a relative path relative to that.
However for package installs or self-build versions you can also set one or all of the variables to an absolute path by defining them.
However this results in non-portable builds.
Note that the prefix path on linux can also be / or /usr which still allows portable builds. Also for an absolute RTTR_BINDIR the prefix path will (almost) always be /.
There are examples (especially involving symlinks) where the detection of the prefix path may fail. In this case one can set the environment variable manually or build with absolute paths.
