class MinimalGameHandler:
"""
The :class:`MinimalGameHandler` class takes care of the interface to the ALE and tries to do nothing else. It's
meant for advanced users who need fine control over every aspect of the process. It has many functions that are simply
wrappers of the underlying ALE but with pythonic names/usage.
Parameters
----------
rom : byte string
Specifies the directory to load the rom from. Must be a byte string: b'dir_for_rom/rom.bin'
frame_skip : int
Default 4. Number of frames to skip inbetween action. This sets frame skip on the Stella environment
show_rom : boolean
Default False. Whether or not to show the game. True takes longer to run but can be fun to watch
"""
def __init__(self, rom, frame_skip=4, show_rom=False):
# set up emulator
self.ale = ALEInterface(show_rom)
self.ale.setInt(b'frame_skip', frame_skip)
self.ale.loadROM(rom)
# setup gamescreen object. I think this is faster than recreating an empty each time
width, height = self.ale.getScreenDims()
self.gamescreen = np.empty((height, width, 1), dtype=np.uint8)
def reset(self):
self.ale.reset_game()
def step(self, action, clip=None):
reward = 0
if clip is not None:
reward += np.clip(self.ale.act(action), 0, clip)
else:
reward += self.ale.act(action)
return reward
def get_gamescreen(self, converted=True):
self.gamescreen = self.ale.getScreenGrayscale(self.gamescreen)
if converted:
# convert ALE gamescreen into 84x84 image
processedImg = imresize(self.gamescreen[33:-16, :, 0], 0.525, interp='nearest')
return processedImg
else:
# we return a copy here because converted returns a copy also. And its easier for exp replay
return np.copy(self.gamescreen)
def get_game_over(self):
return self.ale.game_over()
def get_legal_actions(self):
return self.ale.getMinimalActionSet()
