Finite State Machines using Alice

1. Finite State Machines using Alice Stephen Cano CIS 4914 Senior Project Wednesday December 5th

2. Project Summary • Motivation: In order to teach AI in a University setting, specifically high level AI algorithms such as Finite State Machines, there needs to be a foundational environment to work in. • Save students the time of building characters or settings for artificial intelligence and instead focus on the algorithms themselves

3. Project Summary • Problem: Can a successful Finite State Machine be assembled in the Alice programming environment? • Alice is a tool made to teach beginners how to program, but contains the ability to easily render a 3D world (free at http://www.alice.org) • Is Alice’s “simple” environment enough to handle high-level programming concepts?

4. Project Summary • Solution: Create a 3D world with a single actor that is controlled by a finite state machine • User interaction adds additional states and extra situations to the FSM • Start simple and build up, seeing what Alice can and cannot handle

5. Literature Search • Anon, http://www.alice.org, Carnigie Mellon (as-of Oct 10th) • Alice tutorials and other work done in Alice • Steve Rabin, AI Game Programming Wisdom 2,Charles River Media (Dec 2003) • What is a Finite State Machine? • Good examples for single-actor FSM • How to debug and enhance your finite state machine • Ian Millington, Artificial Intelligence for Games,Morgan Kaufmann (June 2006) • More basic information around Finite State Machines • “Ant colony” finite state machine involving many actors

6. Work Performed • In Alice, created a single-actor finite state machine • Main actor, the “penguin” character, goes between 3 different states when left to run, and can enter two different states based on user interaction. • Created two “objects”the user can put intothe scene

7. State Diagrams

8. Main functions • Penguin.FSM: • Main “always running” function, had a looped action that shows the finite state machine has entered a certain state. • Example: if in “roam” state, call Penguin.roam, which makes the penguin take a few steps • Also contains a check to see if conditions have been met to enter a new state

9. Main functions • Penguin.Statecheck • Checks the environment of the character to see if the state needs to be changed • Performs the necessary actions for pre- and post-state change processing • Example: Sit down to eat when hungry, turn to run and hide when scared

10. Conclusions: Positive • While missing some high-level functionality, a simple FSM can be built in Alice • Enough functionality exists for the purpose of educational venturesin AI. • Very fun, easy to use

11. Conclusions: Negative • FSM not as “smart” as it could be due to programming limitations • If/Else statements only good available logic • Animations must finish before “moving” on, cannot have multiple threads running to constantly check states • Example: Penguin will not notice fear-enducing skeleton until he is done with his walk cycle • Cannot dynamically add objects to the environment

12. Future Work • Could a more skilled Alice animator create sharper state transitions? • Can the Java base of Alice be directly modified to be more inclusive of AI technology? • Can other AI algorithms also be replicated in Alice? • Is there a better programming environment for educational purposes of AI?

13. Q/A time and quick notes • Thanks to Professor Schmalz, Dr. Dankel, and my fellow Senior class • I wish you all a great winter break, and a great spring semester!