From b64974eb90255208fd997794c0a5195abbee30aa Mon Sep 17 00:00:00 2001
From: Jacob Hilton <jhilton@openai.com>
Date: Sun, 24 Mar 2019 12:27:14 -0700
Subject: [PATCH] build_env now doesn't apply frame stack to retro games twice

---
 baselines/common/cmd_util.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/baselines/common/cmd_util.py b/baselines/common/cmd_util.py
index 419b227..8e0eced 100644
--- a/baselines/common/cmd_util.py
+++ b/baselines/common/cmd_util.py
@@ -75,6 +75,8 @@ def make_env(env_id, env_type, mpi_rank=0, subrank=0, seed=None, reward_scale=1.
     if env_type == 'atari':
         env = wrap_deepmind(env, **wrapper_kwargs)
     elif env_type == 'retro':
+        if 'frame_stack' not in wrapper_kwargs:
+            wrapper_kwargs['frame_stack'] = 1
         env = retro_wrappers.wrap_deepmind_retro(env, **wrapper_kwargs)
 
     if reward_scale != 1: