Building a StarCraft II AI Bot with DeepMind's pysc2 in Python

The article introduces DeepMind's open‑source StarCraft II learning environment (pysc2) and shows how to set up a Python 3.6 environment with the required packages and map files.

Preparation : Install sc2 and import necessary modules, then define a bot class inheriting from sc2.BotAI .

import sc2
from sc2 import run_game, maps, Race, Difficulty
from sc2.player import Bot, Computer
from sc2.constants import *

class SentdeBot(sc2.BotAI):
    async def on_step(self, iteration: int):
        await self.distribute_workers()
        await self.build_workers()
        await self.build_pylons()
        await self.build_assimilators()
        await self.expand()
        await self.offensive_force_buildings()
        await self.build_offensive_force()
        await self.attack()

Mining : Implement a method to train probes and build pylons when supply is low.

async def build_workers(self):
    for nexus in self.units(UnitTypeId.NEXUS).ready.noqueue:
        if self.can_afford(UnitTypeId.PROBE):
            await self.do(nexus.train(UnitTypeId.PROBE))

async def build_pylons(self):
    if self.supply_left < 5 and not self.already_pending(UnitTypeId.PYLON):
        nexus = self.units(UnitTypeId.NEXUS).ready.first
        if self.can_afford(UnitTypeId.PYLON):
            await self.build(UnitTypeId.PYLON, near=nexus)

Building Army : Add logic to construct gateways, cybernetics cores, stargates, and train stalkers or void rays based on unit counts.

async def offensive_force_buildings(self):
    if self.units(UnitTypeId.PYLON).ready.exists:
        pylon = self.units(UnitTypeId.PYLON).ready.random
        if self.units(UnitTypeId.GATEWAY).ready.exists and not self.units(UnitTypeId.CYBERNETICSCORE):
            if self.can_afford(UnitTypeId.CYBERNETICSCORE):
                await self.build(UnitTypeId.CYBERNETICSCORE, near=pylon)
        elif len(self.units(UnitTypeId.GATEWAY)) < 1:
            if self.can_afford(UnitTypeId.GATEWAY):
                await self.build(UnitTypeId.GATEWAY, near=pylon)
        if self.units(UnitTypeId.CYBERNETICSCORE).ready.exists and len(self.units(UnitTypeId.STARGATE)) < 1:
            if self.can_afford(UnitTypeId.STARGATE):
                await self.build(UnitTypeId.STARGATE, near=pylon)

Attack Logic : Define aggressive unit thresholds and issue attack commands when enough units are available, otherwise defend against nearby enemies.

async def attack(self):
    aggressive_units = {UnitTypeId.STALKER: [15, 5], UnitTypeId.VOIDRAY: [8, 3]}
    for unit_type, (fight, defend) in aggressive_units.items():
        if self.units(unit_type).amount > fight:
            for s in self.units(unit_type).idle:
                await self.do(s.attack(self.find_target(self.state)))
        elif self.units(unit_type).amount > defend and self.known_enemy_units:
            for s in self.units(unit_type).idle:
                await self.do(s.attack(random.choice(self.known_enemy_units)))

Advanced Features : The bot collects map data into a NumPy array, visualizes unit positions with OpenCV, and implements a scouting routine using Observers and a robotics facility.

async def intel(self):
    game_data = np.zeros((self.game_info.map_size[1], self.game_info.map_size[0], 3), np.uint8)
    # draw units, structures, and enemy positions using cv2.circle
    flipped = cv2.flip(game_data, 0)
    resized = cv2.resize(flipped, None, fx=2, fy=2)
    cv2.imshow('Intel', resized)
    cv2.waitKey(1)

Finally, the article shows how to launch the bot against Easy, Medium, Hard, and Very Hard computer opponents using run_game with the appropriate Difficulty setting.