imclab/lambdahack

Haskell game engine for roguelike dungeon crawlers

LambdaHack

This is an alpha release of LambdaHack, a [Haskell] 1 game engine library for [roguelike] 2 games of arbitrary theme, size and complexity, packaged together with a small example dungeon crawler. When completed, the engine will let you specify content to be procedurally generated, define the AI behaviour on top of the generic content-independent rules and compile a ready-to-play game binary, using either the supplied or a custom-made main loop. Several frontends are available (GTK is the default) and many other generic engine components are easily overridden, but the fundamental source of flexibility lies in the strict and type-safe separation of code and content and of clients (human and AI-controlled) and server. Long-term goals for LambdaHack include support for multiplayer tactical squad combat, in-game content creation, auto-balancing and persistent content modification based on player behaviour.

The engine comes with a sample code for a little dungeon crawler, called LambdaHack and described in PLAYING.md. The engine and the example game are bundled together in a single [Hackage] 3 package. You are welcome to create your own games by modifying the sample game and the engine code, but please consider eventually splitting your changes into a separate Hackage package that depends on the upstream library, to help us exchange ideas and share improvements to the common code.

Games known to use the LambdaHack library:

• [Allure of the Stars] 6, a near-future Sci-Fi game in early development

Compilation and installation

The library is best compiled and installed via Cabal (already a part of your OS distribution, or available within [The Haskell Platform] 7), which also takes care of all the dependencies. The latest official version of the library can be downloaded automatically by Cabal from [Hackage] 3 as follows

cabal install LambdaHack

For a newer snapshot, download source from a development branch at [github] 5 and run Cabal from the main directory

cabal install

For the example game, the best frontend (wrt keyboard support and colours) is the default gtk. To compile with one of the terminal frontends, use Cabal flags, e.g,

cabal install -fvty

Compatibility notes

The current code was tested with GHC 7.6 and 7.8, but should also work with other GHC versions (see file .travis.yml.7.4.2 for GHC 7.4 commands).

If you are using the terminal frontends, numerical keypad may not work correctly depending on versions of the libraries, terminfo and terminal emulators. The curses frontend is not fully supported due to the limitations of the curses library. With the vty frontend run in an xterm, CTRL-keypad keys for running seem to work OK, but on rxvt they do not. Vi keys (ykuhlbjn) should work everywhere regardless. GTK works fine, too.

Testing and debugging

The Makefile contains many sample test commands. All that use the screensaver game modes (AI vs. AI) and the simplest stdout frontend are gathered in make test. Of these, travis runs one of the sets prefixed test-travis on each push to the repo. Commands with prefix frontend run AI vs. AI games with the standard, user-friendly frontend. Commands with prefix peek set up a game mode where the player peeks into AI moves each time an AI actor dies or autosave kicks in. Run LambdaHack --help to see a brief description of all debug options. Of these, --sniffIn and --sniffOut are very useful (though verbose and initially cryptic), for monitoring the traffic between clients and the server. Some options in the config file may turn out useful too, though they mostly overlap with commandline options (and will be totally merged at some point).

You can use HPC with the game as follows

cabal clean
cabal install --enable-library-coverage
make test
hpc report --hpcdir=dist/hpc/mix/LambdaHack-0.2.10.6/ LambdaHack
hpc markup --hpcdir=dist/hpc/mix/LambdaHack-0.2.10.6/ LambdaHack

The debug option --stopAfter is required for any screensaver mode game invocations that gather HPC info, because HPC needs a clean exit (to save data files) and screensaver modes can't be cleanly stopped in any other way.

Further information

For more information, visit the [wiki] 4 and see GameDefinition/PLAYING.md, CREDITS and LICENSE.

Have fun!