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Playing on Nulls Royale

Nulls Royale is a fan-run server for Clash Royale. With RoyaleBot, a bot you made with RoyaleGym plays real matches there, card by card. Two steps: train on the version Nulls runs, then play.

1. Train on the Nulls version

Nulls Royale runs game version 15.535. RoyaleGym plays today's version by default, and a few cards and rules differ between the two. To train on the rules your bot will meet on Nulls, pass client="15.535.29":

from royalegym import make_env

for client in (None, "15.535.29"):
    env = make_env(client=client)
    fire_spirits = next(card for card in env.engine.cards() if card.name == "FireSpirits")
    print(client or "today", fire_spirits.hitpoints)

today 215
15.535.29 217

That one setting switches both the card values and the game mechanics to version 15.535's. It needs royalegym 0.1.24 or newer: pip install --upgrade "royalegym[all]".

In your quickstart.py

In build_env, change RustEngine() to RustEngine(calibration_overrides=client_overrides("15.535.29")), and add from royalegym.rust_engine import client_overrides to the imports at the top of build_env. It changes the battles, so it needs a new bot: change save_dir to a new name too.

How close is it? We checked this setup against 750 short test scenes recorded on version 15.535. The engine put 99.6% of units within a quarter tile of where the game had them and got 99.9% of hitpoints exactly right, and 684 scenes matched on every tick (RoyaleSim 0.1.32, and the same scores on every release since, up to 0.1.42). These are short scenes, not whole battles: over a whole battle, small differences add up. Nulls can also change cards in its own updates.

2. Play it with RoyaleBot

  1. Download the Nulls Royale app (the .apk file) yourself from Nulls' page. RoyaleBot supports Nulls Royale 15.535.13, the version that page has now.
  2. Follow RoyaleBot's setup. It prepares your copy of the app, then royalebot-play --bot <your bot's folder> plays your bot in your matches.

Put AI or Bot in your in-game name, so the people you play know.