Paradigms of artificial intelligence programming: case studies in Common LISP By Peter Norvig has a full chapter on this (ch18), complete with code in Common LISP.
his "Artificial Intelligence: A Modern Approach" is also a good book if you are interested in game AI. 3rd edition just came out recently On Fri, Aug 13, 2010 at 12:33 PM, Alan <a...@malloys.org> wrote: > 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 -- Omnem crede diem tibi diluxisse supremum. -- You received this message because you are subscribed to the Google Groups "Clojure" group. 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