Funny you should mention this - I was about to post a question about my own game when I saw your article. My issue is, I assume someone has written minimax and/or alpha-beta pruning in Clojure (or a java library that's easy to interop with). My case is slightly different in that the turn order is not fixes - sometimes player X goes twice in a row - but it ought to be pretty simple to plug into a standard AI library. Does anyone know where I can find such a thing?
On Aug 13, 6:51 am, Mike Anderson <mike.r.anderson...@gmail.com> wrote: > Hello all, > > I've recently been working on a game development project in Clojure > which is now starting to bear fruit. I thought people here might be > interested, and that it would be worthwhile to share some experiences > and perspectives. > > The project is a steampunk-themed strategy game, and a playable in- > development version is available here: > > http://mikera.net/ironclad/ > > Overall, I think Clojure is a fantastic language for game development. > Some thought on what makes it really compelling: > > 1. Immutable data structures work surprisingly well for games. I > represent the entire game state with a big defrecord, and the main > engine loop is basically: > a) Get commands from player / AI (e.g. "Move unit from A to B") > b) Convert each command into set of atomic updates ("Remove unit > from A", "Add unit to B") > c) Apply updates sequentially to the game state > d) Trigger any feedback to player e.g. animations, sounds > > 2. Concurrency support has been very helpful. With immutable game > state, it has been trivial to separate the game engine from the > renderer from the AI calculations - each effectively gets to operate > on its own "snapshot" of the entire game state. This can be a big > headache in many game engines that have to mediate access to a single, > mutable game state. I can also see even greater benefits when I > finally start adding some multi-player features. > > 3. High level, functional programming works great for rapid, iterative > and dynamic development. Of all the languages I've used, Clojure has > probably been quickest in terms of time required to add a given new > piece of functionality. For example, the map generator code probably > only took about 30 minutes to write, pretty good for a fractal > landscape generation system! > > 4. The Java interoperability support is fantastic - definitely counts > as one of the "killer features" of Clojure. I've been able to reuse a > lot of Java code libraries, both my own and standard libraries such as > Swing. As an example, I have a well optimised immutable persistent 2D > grid data structure in Java (basically a very efficient, spatially > partitioned map from (int,int) to Object) that I have been able to use > pretty much seamlessly in Clojure thanks to extend-protocol and > similar. > > Some interesting observations / discoveries / surprises in the > process: > > 1. The game worked first time on Mac and Linux, despite having been > tested exclusively on Windows. Great kudos to to both the Java > platform and the Clojure libraries! > > 2. Reflection is *really slow*. After getting 20-100x speedups from > eliminating reflection warnings in the AI code, I now treat any > reflection warning in code other than one-time setup code as a bug to > be fixed immediately. > > Finally, here are some things I think could be great improvements to > Clojure in the future from a game developer's perspective: > > 1. Better support for primitive parameters / return values / unchecked > arithmetic - in performance sensitive code, these are pretty much > essential. In a few cases in the graphics and AI code, I've had to > drop back to Java to get the performance I need. > > 2. It would be great to reduce the amount of memory allocations. Yes, > I know memory is plentiful and GC is very cheap, but it's still not as > cheap as stack allocation and any noticeable GC pauses are not good > for the player experience in interactive games. For this reason, I > find myself using reduce and indexed loops a lot more than I guess > would normally be idiomatic, and conversely tend to avoid some of the > lazy constructs and functions that generate sequences. While Clojure > is great for a strategy game, I'd probably hesitate to use it for a > real-time 3D game. > > 3. I think it would be great to have better support for circular > references - perhaps a two-pass compile? The reason this is > particularly acute in game development is that different subsystems > have quite a lot of inter-dependencies. AI evaluation system needs to > understand game state/engine so it can evaluate a position. Game state/ > engine needs to understand units so it can manipulate them. Units need > to understand AI evaluation system so they can decide which actions to > take...... obviously it's possible to work around all this, but it's a > major pain, adds complexity and means that you need to structure code > to manage dependencies rather than in logical modules (which would be > easier to manage and maintain!) > > Would love to hear thoughts, and particularly any other experiences > people have had in using Clojure for game development! > > Mike. -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
