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Add FireResetEnv and enable terminal_on_life_loss for Atari #124

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Merged
dnddnjs merged 1 commit into from
May 17, 2026
Merged

Add FireResetEnv and enable terminal_on_life_loss for Atari #124

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16 changes: 15 additions & 1 deletion 3-atari/env.py
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,18 @@

gym.register_envs(ale_py)


# Breakout (and a few other games) require pressing FIRE to launch the ball
# after each reset / life loss. AtariPreprocessing only does NOOPs, so without
# this the agent wastes a lot of frames waiting for a random FIRE.
class FireResetEnv(gym.Wrapper):
def reset(self, **kwargs):
self.env.reset(**kwargs)
obs, _, terminated, truncated, _ = self.env.step(1) # FIRE
if terminated or truncated:
obs, _ = self.env.reset(**kwargs)
return obs, {}

ENV_IDS = {
"breakout": "ALE/Breakout-v5",
"pong": "ALE/Pong-v5",
Expand Down Expand Up @@ -47,10 +59,12 @@ def make_env(args):
noop_max=30,
frame_skip=4,
screen_size=84,
terminal_on_life_loss=False,
terminal_on_life_loss=True,
grayscale_obs=True,
scale_obs=False, # keep uint8; we normalize in the model
)
if "FIRE" in env.unwrapped.get_action_meanings():
env = FireResetEnv(env)
env = gym.wrappers.FrameStackObservation(env, stack_size=4)
return env

Expand Down