1. The Halo 2 AI In 10 Minutes or Less Damián Isla Bungie Studios

2. Halo First person shooter for XBox Interesting sci-fi world
Lots to do (combat, exploration, vehicles, weapons)
Lots of decisions to make
Slower-paced More strategic in nature?

3. The AI Single-player campaign only (no multiplayer) Character-based
Enemies
Large variety
Clear behavioral patterns for the player to learn and exploit
second lifespans
Allies
Not terribly effective
“Kid brothers”
~10 seconds or ~30 minutes

4. The “I” in “AI” Behave Strongly agent-based approach
Perception and world-modeling
Each AI maintains mental world model
Internal mental object-state updated according to perceivability via the “senses” (e.g., line of sight, sound events, etc.)
Perception sharing (via explicit communication)
Behavior
Take cover when taking damage
Uncover hidden enemies
Use vehicles when appropriate
Joint behaviors
Skills
Use weapons appropriately
Drive vehicles
Navigate the environment
Strongly agent-based approach
“Strategy” controlled through scripting
Behave

5. Behavior Decision-making: Behavior DAG (HFSM)
Behavior: a program that takes temporary control of the actor in order to get something done.
Good
Intuitive
Modular
Scalable (more IS better)
Bad
Memory is hard
Debugging is hard
Never really that simple

6. An ethological interlude…
Baerends, The Functional Organization of Behavior, 1976

7. What about Reasoning and Planning?
Spatial Reasoning
Firing point selection
Path-planning A*
Dynamic obstacle interaction
… but no concept-reasoning or action-planning

8. So in the end… Second-to-second decision-making Reactive in nature
Closer to A-Life than classical AI
Closer to animal than to human intelligence