Starcraft AI blog

BWAPI will tell you how much gas remains in a visible geyser, even if the enemy owns a refinery over it. Human players get to see how much gas is in a bare geyser that they can see, or in one of their own refineries, but they can’t see enemy gas. It’s a BWAPI bug that gives away strategically valuable information. I noticed immediately when I wrote resource tracking for Steamhammer, but only filed github issue 847 today because I was too lazy to check past issues and change logs to find out if it was already known.

Has this never been noticed before? That’s hard for me to believe. Did I miss something among the BWAPI issues? I suspect that relatively few bots do resource tracking (even a bot as strong as BananaBrain will expand to an empty base). But some do, and surely somebody must have realized that BWAPI’s behavior doesn’t match Starcraft’s behavior. Or do bot authors really lack the game knowledge?

The bug doesn’t affect Steamhammer’s behavior much in practice—yet. Steamhammer only uses the resource amounts in deciding what base to expand to, and if it’s taking a destroyed enemy base then the enemy refinery was normally also destroyed, and Steamhammer gets to see the remaining gas amount then. But before long I want Steamhammer to start using resource amounts for strategy calculations, and then it will make a big difference if it uses its illicit access to the true enemy gas reserves. Knowing how much gas was mined is a big clue to what the enemy has done and is doing.

I’m thinking I’ll add a workaround to the bug, so that Steamhammer doesn’t collect information that it should not have.