in sonic_on_ray/sonic_on_ray.py [0:0]
def __init__(self, env, k):
"""Stack the k last frames.
Returns a lazy array, which is much more memory efficient.
See Also
--------
baselines.common.atari_wrappers.LazyFrames
"""
gym.Wrapper.__init__(self, env)
self.k = k
self.frames = deque([], maxlen=k)
shp = env.observation_space.shape
self.observation_space = spaces.Box(low=0, high=255,
shape=(shp[0], shp[1], shp[2] * k),
dtype=np.uint8)