Lane's Blog » RSAGL

ANN: Roguestar-0.4.0.1

Christopher Lane Hinson — Fri, 18 Jun 2010 02:32:08 +0000

Roguestar is a science fiction roguelike game written using Haskell and OpenGL. It is in the early stages of development. At this time, it is not a winnable game.

$ cabal install roguestar-engine
$ cabal install roguestar-gl
$ ~/.cabal/bin/roguestar

- or -

$ git clone http://www.downstairspeople.org/git/roguestar.git
$ cd roguestar
$ git checkout 0.4.0.1
$ make install

New gameplay features:

Melee combat, sundering and disarming attacks
Weapons can sometimes overheat or explode
Gateway teleportation between planets
Use material-spheres to craft new tools
Use material-spheres to heal
Tab-completion of typed commands
Compass directions to significant artifacts
“Jump” short distances by teleporting

New objects:

Chromalite material spheres
Metallic material spheres
Gaseous material spheres
Energy sabres and fleurets
Gateways
Monoliths

New graphics features:

Randomly generated sky spheres and landscapes
Unique fractal trees
Zoom-in/zoom-out

Changes under the hood:

Major re-write of the RSAGL FRP architecture
Multi-threaded 3D scene assembly and rendering
Multi-threaded, anticipatory engine
Various OpenGL performance improvements

For more information, links to the manual and git repository, visit http://roguestar.downstairspeople.org.

Check it out!

FactoryArrow

Christopher Lane Hinson — Sun, 09 Aug 2009 19:21:29 +0000

I’ve been playing around with an Arrow concept, which to my knowledge is original. I’ve decided to call this a FactoryArrow:

newtype FactoryArrow m n a b = FactoryArrow { runFactory :: m (Kleisli n a b) }

Where m and n are Monads. m is a single-pass initialization monad, while n is a multiple-pass working monad. The arrow supports all of the standard accessory arrow typeclasses, including ArrowLoop if n implements MonadFix, and ArrowApply if m and n are the same.

This arrow simply captures a two-phase initialize-and-run design pattern.

To the best of my imagination, there cannot be a corresponding useful FactoryMonad. I would be extremely interested if anyone can contradict me on that point.

My current interest is in using the FactoryArrow as a replacement for the mealy-style arrows by using IORefs (or potentially even STM transaction variables) to store automaton states instead of unevaluated thunks.

The corresponding implementation as of the time of this writing.

Vec is Good

Christopher Lane Hinson — Tue, 05 May 2009 19:45:47 +0000

Last night I checked out Scott E. Dillard’s Vec library. It’s a good, fast, pure implementation of the basic matrix operations applicable to 3D graphics. Switching to Vec has shaved off quite a bit of time from one of my demo apps and relieved me of the need to maintain my own matrix manipulation code, which was causing me repeated headaches.

It’s very heavy with MPTCs, fundeps, and type families, which will cause ghc to render some pretty inane error messages, but if you’re already accustomed to this then it’s actually very straightforward to use.