This is a page of resources for the various tools discussed in Rob Zubek and Ian Horswill’s GDC 2023 AI Summit talk.

GDC 2023 talk: Logic Programming in Commercial Games

Interactive demos:

  • MicroCoG can see an interactive demo of the City of Gangsters social inference system running against a CoG game save file.
  • Imaginarium: download the release, run it, hit escape to go to the main menu, and then choose one of the example generators and press one of the buttons at the top of the screen. See the Imaginarium tutorial for more info.

Repos for different AI tools:

  • TELL: Typed, Embedded Logic Language
    This lets you do simple logic programming tasks inside C# code, and mix-and-match LP and C#. It’s a limited version of logic programming; it doesn’t support Prolog’s matching of complex terms (Prolog’s data structures), or the cut (!) operation. Used in an unannounced SomaSim project. See the TELL tutorial for more info.
  • TED: Typed, Embedded DATALOG
    This is like TELL, except it executes bottom-up instead of top-down. Note that it is a not a proper version of datalog. It doesn’t support recursion and its semantics are somewhat Prolog-like. It’s being used for large-scale city simulation and an unannounced SomaSim project.
  • UnityProlog: Prolog interpreter with Unity interop
    This is a nearly full version of ISO Prolog. It was used in SomaSim’s Project Highrise for consistency-checking of assets, e.g. checking that all strings have localization in all languages, there aren’t multiple localizations, etc. It was also used for planning and natural language processing in the experimental game MKULTRA.
  • Step: Simple Text Planner, a logic programming language for text generation
    This is used in the upcoming PCG app from Machine Age Productions for the tabletop RPG, iHunt: Killing Monsters in the Gig Economy by Olivia Hill and Filamena Young. The Step repo is the base interpreter. For an interactive command line and debugger, use StepRepl. If you use it, install the StepHighlighter extension in VS Code. For more information see the Step tutorial
  • CatSAT: Randomized SAT/SMT Solver
    This is a randomized constraint solver used for character PCG in SomaSim’s City of Gangsters. It’s also the underlying constraint solver used by Imaginarium.
  • Imaginarium: Casual constraint-based PCG for table-top RPG players
    This is a system that lets GMs and players create generators for random game artifacts using a simplified English-like syntax. See the Imaginarium tutorial for more information. This is the interactive app. If you want to use the raw system inside your own game, use ImaginariumCore. If you use it, install the Imaginarium extension in VS Code.
  • BotL: A highly optimized logic programming engine for games
    This largely does the same subset of logic programming that TELL does, but goes to extreme lengths to avoid dynamic memory allocation and run-time type checking. It was used in SomaSim’s City of Gangters for social reasoning. At this point, I don’t know that I would recommend using it. The tooling for the other languages is much better and TED is probably just as fast. If we do native code compilation for TED, it will be much faster.