Discord bot to play games together - cause the crowd is just better at it! 🐟🎮

Inspired by Twitch Plays Pokémon. Feel free to contribute or tell us how you like it 🤙

There is a full playthrough of Pokémon Red at https://www.youtube.com/playlist?list=PLuIsDtqkJ0MpAyQ7CmfLjW6awaifDMtuX.

Features

• supports any Gameboy or Gameboy Color ROM
• cross-community play and chat
• local display without lag, direct keyboard input
• recording and video creation
• statistics
• various moderation commands
• configurable, resilient

Lag

Due to the design, the game has the following lag:

• 1s - input, from clicking the button to the game playing the action
• 5s - video, from rendering the footage until it arrives on your machine
• 10s - reaction, from clicking the button until you see the moment on your screen

Get started

As of today, we are not planning on hosting the bot ourselves, or making global events available to everyone.

We encourage you to download the bot and self-host your own events! 👍

Nonetheless, if you know someone who hosts the bot already and has an event running, you can easily join their event with your community.

Join existing event

To participate in an ongoing event with your community, you need to add the bot to your server. Ask the owner of the event for an invite-link.

Once the bot is part of your server, use the slash-command /host mirror in the channel you would like to dedicate to the event.

The bot creates the stream mirror, and a thread for cross-community chat.

For best experience, we recommend the following settings:

• disallow Send Message, allow Send Messages in Threads (except for the bot)

  

• set slow mode of 5 seconds for the thread

  

Host yourself

Discord

Create a bot in Discord. Therefore, visit the Developer Portal. Go to Applications and click New Application. Walk through the dialog and set everything up to your liking.

Go to the Bot section and copy your token (it will only be shown once). Ensure to tick:

• Server Members Intent and
• Message Content Intent

Create an invite-link to join the bot to servers by going to the OAuth2/URL Generator section.

Under Scope, check:

• bot
• applications.command

Select the following Bot Permissions:

• Read Messages/View Channels
• Send Messages
• Create Public Threads
• Send Messages in Threads
• Manage Threads
• Attach Files
• Use Slash Commands

The invite-link is shown in the box below.

Application

Download the latest version from our release section. Run it from console using

# Example: java -jar Discord-Plays-1.0-standalone.jar MzE2OTA4Mzk0OTQ0OTQ2NTgx.XbBkcJ.TpW6sUjEoNGv539Lxi-eqfbCl4R
java -jar <name_of_the_jar> <your_discord_bot_token>

On first startup, it will create a config.json file, which you can freely edit to your needs. At minimum, make sure to configure romPath and owners. Latter will be the ID of your own Discord account.

The bot should be up and running now. Start the game emulation using /owner start. At this point, all participating communities can set up their stream by using /host mirror, which will create the message containing the stream, the interaction buttons and a thread for displaying statistics and chatting.

Initially, input is locked for everyone except you (the owner). To unlock input, run /owner lock-input lock:False.

As owner, it can be helpful to occasionally run the game locally without lag and control the game directly. This can be done using /owner local-display activate:True, optionally even with sound. The controls are:

• WASD or ↑←↓→
• A: Q, SPACE
• B: E, BACKSPACE, ESC
• Start: R, ENTER
• Select: T, DEL

Overview

The permission system is divided into 3 roles:

• Owner - responsible for the event, full access, that's you
• Host - responsible for streaming the event in their community, moderators
• User - everyone else

Owner

Owners need at least Admin permission in Discord and are configured manually in the config, or via /owner add-owner. The main commands are /start, /stop and /lock-input.

To notify all users, you can use /global-message (banner in the stream itself) and /chat-message (message in the threads). Troublemakers can be excluded from the event with /ban (undo by editing the config).

Configure the event to your liking using /game-metadata and use /clear-stats when starting a new run.

Recording

The system automatically records the game by saving frames as pictures in the recordingPath specified in the config.

This consumes around 2 GB per 24h of footage.

The images can be turned into a video (.mp4) by running the /owner create-video command, giving it the name of the folder, e.g. 2023-02-27. The video is created in the same folder.

The command requires the system to have ffmpeg installed.

Auto-save

The system lacks a fully automatic save mechanism. Because of that, it is necessary to manually save the game sometimes.

To ease that workflow, the bot automatically reminds all owners once per day (see autoSaveRemindAt in the config) to save the game, and walks you through a semi-automatic save routine specialized for Pokémon.

This routine can also be triggered manually using /owner save.

Host

Hosts are, by default, all users with Moderator permission in Discord. This can be configured with Discords built-in integration settings.

Hosts can create the actual stream message and thread in a channel of their community using /host mirror. To stop the stream for this community, just delete the bots message or the thread. Afterwards, a stream can be started, for example in a different channel, with the same command again.

The /host community-message command allows to attach a message to the stream, readable only within this community.

Contributing

Thanks for considering improving this project - we hope you like it 🤙

Feel free to post all your ideas as issues. If you want, you can try to implement some of them and propose a Pull Request. As of now, there are no guidelines you have to follow - just try to write readable code 🙂

Tech Stack

The main technologies being used are

• Kotlin
• Gradle
• JDA as Discord framework
• Coffee GB as emulator

Architecture

The code base is divided into several main packages:

• Discord
• Local
• Emulation
• Stream

The flow starts in Main.kt, starting the bot using the Config.kt and booting up all services, wiring them up.

Game emulation is represented and controlled by Emulator.kt. Almost all flows start with invoking a command in either OwnerCommands or HostCommands, which usually end up triggering a method in the main controller class DiscordBot.

The emulator pushes the graphics to StreamRenderer, which scales the game image, adds overlays and more. From there on, all rendered frames are exposed mainly to DiscordBot, LocalDisplay and FrameRecorder.