GymEnv should not show a plot when plot=False

[ryanjulian]

No description provided.

[zhanpenghe]

I have investigated this before and I think the problem is the video recorder for gym environment.
class GymEnv(Env, Serializable): def __init__(self, env_name, record_video=True, video_schedule=None, log_dir=None, record_log=True,

A quick fix could be setting the default value of record_video to False and the plot will not show up.
I am not sure if tensoflow allows recording video without rendering .

[ryanjulian]

Hmm sounds good. I think we should preserve the invariant that record_video=True will successfully record a video (even if that means ignoring plot=False). The ideal is for gym to record off-screen, but I'm not sure that's supported.

[jonashen]

I have determined that it is impossible for gym to record off-screen, because the downloaded video is built from a series of static RGB frames, and it retrieves these frames through frame = self.env.render(...), and gym's core render function by default must draw out the window in order to capture the RGB frame through internal screen capture.

In short, plot=False cannot produce a recorded video. How should we proceed?

[ryanjulian]

I think it's fine to require plot=True to guarantee recording.

[jonashen]

When plot=False, it will still display the window as well as record. Should we leave that as well, or simply turn off window display (and thus also turn off recording)?

[ryanjulian]

IMO the correct behavior is to turn off recording when plot=False. It should probably be an enum option rather than 2 booleans which interact, but c'est la vie.

We will have another opportunity to address this when we replace rllab.Env with gym.Env.

[ryanjulian]

See rlworkgroup/garage#43