Gemini Rising AI - Introduction

When I went looking for articles about game AI that went beyond the most basic level I had a hard time finding any. Most articles were more interested in defining one basic concept and providing an easy, "Hello World" example than diving deep into solving real problems in a real game.

I'd like to change that for future programmers like me looking for guidance.

I'm going to write a series of posts about my experiences crafting the AI for my game, Gemini Rising. Since I was learning as I go I'm sure there are going to be mistakes; I'd love to hear about them!

UPDATED 2020-07-13: Added 'game-ai' tag.


Here are the solutions I tried, in roughly chronological order:

  • Lua scripting with coroutines
  • Behavior trees
  • Goal-oriented action planning
  • Behavior trees (but better this time)


My goals shifted over time, but here is the list in priority order:

  • Fun experience for the player. Above all else, the game had to be fun for the player.
  • Learn something about game AI. In all my wandering, I wanted to learn more about making good AI for games.
  • Be easy for me. I'm jealous of my time as a hobbyist gamedev, so anything that required too much brainpower to adapt, use, modify, or fix was right out. I didn't need visual designers, but if I couldn't fix AI problems relatively easily then this wasn't the method for me.
  • Be predictable. This one was added later; I'll talk about it more when it becomes important.

The Posts

Here are the posts that are ready.

  1. Lua Scripting
  2. Behavior Trees
  3. Goal-Oriented Action Planning