Twitch Plays Checkers, or Twitch Loses Checkers, is an AI written in Python that challenges the audience on Twitch to a game of checkers. Originally Andrew and I wanted to challenge each other to write an AI and have our Raspberries Pis play each other, but we decided to pivot, and save that challenge for another day. I also wanted to write in C++ and Python, but I couldn’t figure out the necessary libraries in a reasonable time period.

I was tasked with building the game rules and the checkers AI; Ariel, the interaction with Twitch; and Andrew, the drawing of the board. It turns out that I had almost forgotten how to play checkers and didn’t realize that there were a lot of rules to consider when validating moves. After I thought I had the basic board mechanics in working order, I moved on to build the checkers AI that would play against Twitch. I thought about trying to implement a dominant strategy, but I didn’t have enough time to do all of the reading. Thus, I was left with writing a simple greedy algorithm to find the best move given a board state. While I would have must preferred to write this algorithm in C++, I did learn a bit about “passing by value” in Python: since everything is passed by reference by default, I had to manually deep copy objects to pass them by value.

Andrew wrote the functions to draw the checkerboard and the pieces on the board using OpenCV. Instead of streaming video, Andrew decided to update a .png file with the new board state and stream the picture to Twitch. Ariel wrote the part to capture the Twitch chat, parse the valid commands, and make a move.

In the end, our three parts came together quite nicely. I had to work out a few bugs in the game dynamics, but we had a good working prototype for the demo. There was one unfixed bug however: pieces on the left edge of board could not move unless that move was a jump. I couldn’t readily find the bug so I called it done and went to sleep. This wasn’t a huge project, nor overly impressive, but it had been a while since my last hackathon project and it felt good to accomplish something.