Boxroom-Plus

Adds support for launching custom applications, emulators, and non-Steam games directly from BOXROOM.

Instead of always launching through Steam, Boxroom-Plus checks for a launch.json file inside a game's cache folder. If found, the specified executable is launched with optional arguments and working directory settings.

If no launch.json exists, BOXROOM behaves normally and launches through Steam.

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Features

• Launch custom executables
• Launch emulators with ROM arguments
• Launch non-Steam games
• Per-game launcher configuration
• Automatic fallback to normal Steam launching
• No changes required to existing Steam games

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Requirements

• BOXROOM
• MelonLoader
• .NET Framework compatible with BOXROOM

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Installing MelonLoader

1. Download MelonLoader from https://melonwiki.xyz
2. Run the MelonLoader installer.
3. Select BOXROOM.exe.
4. Install the latest stable version.
5. Launch BOXROOM once.
6. Verify the following folders were created:

BOXROOM/
├── Mods/
├── UserData/
├── MelonLoader/

7. Close BOXROOM.

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Installing Boxroom-Plus

Copy:

BoxroomPlus.dll

to:

BOXROOM/Mods/

Launch BOXROOM.

You should see:

Boxroom Plus Loaded!

in the MelonLoader console.

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launch.json

Place a launch.json file inside the game's cache directory:

AppData\LocalLow\NestedLoop\BOXROOM\steam_cache_v2\<AppId>\

Example:

steam_cache_v2/
└── 900000001/
    ├── game.json
    ├── screenshots
    └── launch.json

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Example: Launching Mesen

{
  "Executable": "C:\\Users\\USER\\DOCUMENTS\\Mesen_2.2.0_Windows\\Mesen.exe",
  "Arguments": "\"C:\\Users\\USER\\DOCUMENTS\\Mesen_2.2.0_Windows\\Super Mario Bros. (World).zip\"",
  "WorkingDirectory": "C:\\Users\\USER\\DOCUMENTS\\Mesen_2.2.0_Windows",
  "UseShellExecute": true
}

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launch.json Fields

Executable

Required path to the executable.

Arguments

Optional command line arguments.

WorkingDirectory

Optional working directory. If omitted, Boxroom-Plus automatically uses the executable's folder.

UseShellExecute

Optional. Defaults to true.

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Example: RetroArch

{
  "Executable": "C:\\RetroArch\\retroarch.exe",
  "Arguments": "-L \"C:\\RetroArch\\cores\\snes9x_libretro.dll\" \"D:\\ROMS\\Super Mario World.smc\""
}

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Example: Non-Steam Game

{
  "Executable": "C:\\Games\\Minecraft\\MinecraftLauncher.exe"
}

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Fallback Behavior

If launch.json is missing:

BOXROOM -> Steam Launch

If launch.json exists:

BOXROOM -> Custom Executable

Existing Steam titles continue working exactly as before.

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License

MIT License