No SDL in current binary

[d9w]

Hi,

I was wondering why SDL=OFF was provided in the current build_tarballs.jl in ArcadeLearningEnvironment_jll.jl? I realize this makes SDL a requirement, but since it is a requirement for the base Arcade-Learning-Environment that seems reasonable to me. Without it, this package can't render games (or at least as far as I understand), since setBool(ale, "display_screen", true) fails when not using -DSDL=ON.

[findmyway]

@jbrea might know more details about the build_tarballs.jl file.

[jbrea]

I never needed rendering through SDL, because it is rather easy to render the images directly in julia (see e.g. here). What is your usecase?

[d9w]

Hi, thanks for the quick response. My use case is displaying video of trained agents, which I do using

function record(ale, directory::String)
    setBool(ale, "display_screen", true) # for live display
    setBool(ale, "sound", true) # for live display
    setString(ale, "record_screen_dir", directory) # for recording
    setString(ale, "record_sound_filename", string(directory, "/sound.wav")) # for recording
end

I'll admit that I hadn't seen that definition of display. I find that the overhead of getScreenRGB is high compared to displaying the ALE with SDL and the flag setBool(ale, "display_screen", true), but I don't have the numbers right now and I haven't tested the rest of this display function.

Also, without SDL, I don't think you can get sound, ie use the setBool(ale, "sound", true) flag, although maybe there's a way to recover the sound from the ale Ptr? It seems a shame to wrap that when the ALE already does it though.

[jbrea]

OK. This requires a bit of work, because we don't yet have SDL_jll. There is already SDL2_jll, but it is incompatible. Once we have SDL_jll it is most likely a very simple PR to change ArcadeLearningEnvironment_jll. I can probably have a look at this at some point during the next 14 days, but please feel free to go ahead yourself, if you find the time.

[d9w]

so here's the SDL_jll:

JuliaPackaging/Yggdrasil#1685

unfortunately it doesn't compile on all systems, so if you want to look into it further feel free, otherwise I think it would be okay to use it in the ALE given the systems it does support

[aviks]

Been a while, but we now have libSDL available as a jll via SDL12_compat JuliaPackaging/Yggdrasil#6003 if you folks are still interested.