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Show HN: Twitch Plays Doom

113 points by dddanmar ↗ HN
This is the inevitable post after jeff_harris released restful-doom https://news.ycombinator.com/item?id=14919534

twitch-plays-doom is a Python Twitch IRC->restful-doom proxy to control doomguy with a staggering 8 second delay.

The project was Saturday night's 'I wonder if I can make this work' session. Since it's been live there has been a team of four successfully make it to half way through E01M01.

I've since added godmode to the chat (you can guess the command).

This was fun, hope others get some enjoyment out of it.

Twitch Stream/Chat https://www.twitch.tv/dddanmar/

twitch-plays-doom https://github.com/dddanmar/twitch-plays-doom/

restful-doom https://github.com/jeff-1amstudios/restful-doom/

chocolate-doom https://github.com/chocolate-doom/chocolate-doom/

42 comments

[ 3.0 ms ] story [ 99.9 ms ] thread
_Marak_
Type `iddqd` to toggle god mode

Edit: I'm getting downvotes for this? It's in the posted source code: https://github.com/dddanmar/twitch-plays-doom/blob/master/tw...

_Marak_
It looks like there are two factions forming over the control of `iddqd` command.

It's a battle of trying to keep the marine alive versus killing him. Every-time someone types iddqd, god mode is toggled.

God mode makes the character invincible, without god mode on the marine dies in a few seconds.

dddanmar
This has been my favourite part of the entire stream, didn't expect factions forming at all!
wernercd
You don't expect factions? Religious wars have been raged over tabs vs spaces... tab is 2, 3 or 4 spaces... bracket on this line vs the next...

Factions are normal and I would expect them to coalesce, polarize and get more extreme over time.

Sol-Savage
Ahh, fighting. The ultimate form of togetherness.
Liru
Okay, I understand the reasoning for most of these choices, but what kind of barbarian argues that a tab should be 3 spaces?
dagmx
I believe that was the standard at Google for a while?
westmeal
Auuugh that'd drive me insane
sergiotapia
I don't get that war - configure your editor to convert your tabs to spaces. Precision.
zaphar
Ah, but then you commit and someone else pulls the source code down and their carefully crafted N space per tab setting is now worthless since you decided how long tabs should be for them.

Then they post an angry rant on some mailing list about how forcing tabs to spaces forces people with various reading disabilities into a tabstop setting that makes it hard to read.

And before too long it's devolved into the same old Tabs vs Spaces debate.

tokenizerrr
Before that, your diff looks ugly and you generate tons of merge conflicts by useless indentation changes.
sergiotapia
But... your team just enforces a style. No debate. Two spaces for Ruby I've seen almost everywhere. Two for Elixir, same. Go has go fmt. This hypothetical of different spaces is killed before it happens.
zaphar
Having a style ends the debate yes. Configuring your editor to automatically replace tabs with spaces does not end the debate. It starts it.
NTripleOne
You mean convert spaces to tabs, right? ...right?!
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exikyut
Okay, I've been watching this for a few minutes, and... the 8 second delay is FAR too long.

Doom is simply too interactive. You need to be able to control it in realtime.

I recommend three things:

- Slow the delay right down, and possibly make it adjustable via chat commands. A 500ms-1s delay is honestly going to be the best possible thing here. Yes, some players will lag too much and won't be able to play at those latencies - which is why you make it adjustable.

- Show, inside the video stream, the command that is currently executing, and the username executing from. This will create a unique tuple that will allow players to figure out the sync for themselves.

- A consensus system that tallies up the next key to press, TpP-style, might be a good idea. Right now everyone's fighting to cooperate because it's concatenating everyone's actions together.

unkown-unknowns
I think the delay is due to Twitch itself.
dddanmar
100% - the delay is as low as I can get it.

Twitch uses RTMPE for the most part, it's always going to be a little delayed. It's a decent box, compression is on, connected to fibre internet.

If anyone has any ideas of reducing latency I'd love to hear it!

maccard
No agfiliation, but Mixer/Beam [0] had a much lower delay than twitch. It unfortunately has the issue of not having anywhere the popularity of twitch.

[0] https://mixer.com

narrowtux
Mixer also has the possibility to add buttons directly to the stream, so viewers can use WASD and stuff on their actual keyboards.
spyhi
Does the irc bot you imported use websockets? I've been researching how to do a Twitch-plays game in Unity/C# and am thinking websockets to avoid rate limiting, but was wondering how much that'd do for latency, given it's push-based instead of polling.
dddanmar
You can take a look at the code on Github, it's a very straight forward Python IRC client.

The delay experienced is all in the stream broadcast back to the Twitch servers and on to the viewers.

When I'm watching the chat and also watching the local view of Doom the commands are executed almost instantly. It then takes ~8s to show on my Twitch view. When I started it was around 15s but some tweaking in OBS has brought that down a bit.

MichaelGG
Why not time dilate? Could make it a variable setting that users can control. At some setting, it'd be fast enough to send commands and win fights without god mode.

Or you could execute the command for a second, then pause the game execution. Make it closer to turn-based Doom.

sli
Allowing a reasonable number of consecutive actions might help, too. Like if I want to go forward two steps and turn 90 degrees to the right, I could send "wwddd." Not as necessary in Twitch Plays Pokemon, but could do wonders here.

But as mentioned, it would have to be capped to some number to prevent abuse.

wcummings
The delay is lower for "partners" on Twitch I think, so they can technically support it, just not for every stream.
exikyut
Oh wow. The 8 seconds is Twitch?! Yikes.

I am unfortunately completely ignorant of how you actually send data to Twitch, but can you use H264? It has an "ultra-low latency" mode.

Edit: Hmm, you're on OBS. Maybe you could stream using some uncompressed low-latency option from OBS to ffserver, then reencode on ffserver to low-latency H264. Alternatively, you could use ffmpeg with its X11 capture option, pointed at eg Xvfb.

PhasmaFelis
Just to piggyback on this--a friend of mine lives across the country and I've been wanting to watch her play games and kibitz like we used to, but we can't find any video streamer or screencaster that doesn't have either ~10sec delay or unacceptably awful video quality. We've tried Twitch, Skype, and Steam streaming so far. Any ideas out there?
detaro
As someone mentioned below, https://mixer.com/ seems to be the current king of low-latency, but it seems like they only allow public streams.

And Discord just rolled out a beta for screen-sharing, also something to keep an eye on maybe.

dddanmar
Showing the executed command and who on screen for syncing purposes is a great idea, I'll take a look at that now!
lillesvin
Yeah. This sort of feels like after Twitch Plays Pokemon when everyone was doing Twitch Plays XYZ. Someone did Twitch Plays Super Meat Boy and it was completely impossible to get anywhere. I appreciate the effort put into setting up the whole thing, I just wish people would stop to consider if it's even possible.
Rampoina
I played it for a while, it was fun but a bit frustrating having to fight the people trying to turn god mode off.
dddanmar
God mode is now turned on without an option to turn it off.
tenryuu
I once played an interactive doom on Mixer (Then Beam)

Worked well for showing off the platform, since there was really a low latency. Since it uses it's own interactive input, and not relying on IRC for interaction, so it's UX is considerably more user friendly... if you want to sign up for a Microsoft Xbox live account to use it

dingo_bat
> Your message was not sent because it is identical to the previous one you sent, less than 30 seconds ago.

:O I can't fire fast enough!

dddanmar
I saw someone with an idea to escape the Twitch message rules:

f - f - f - f

wcummings
Hard to play a real-time game with a 7 second delay...
tokenizerrr
You should probably remove the toggle godmode command and force it to on. It's trivial to ruin progress with a strategic iddqd.
dddanmar
Done. God mode stuck on now.
cordite
The game seems paused and I mostly just hear some soft creepy music
dddanmar
It crashed ;-(. Made a few small changes and it's back up.
jeff_harris
thanks dddanmar, very cool!
dddanmar
You've done all the hard work here, really appreciate your release that gave me a fun Saturday night!

My part took all of four hours to write, setup, deploy and post.

At this point I'm going to pull the stream down, been going 5 days now with a few crashes in Doom that are getting a little frustrating to debug.

Thanks again! This was great fun!!