[BUG] Playing the Epic Games version of Subnautica via Steam in home streaming

drbob

Currently adding the Epic Games Store version of Subnautica to Steam as a non steam game by adding subnautica.exe from the game's installation directory does not work to launch the game from within steam.

This is because running subnautica.exe directly results in the subnautica icon appearing briefly in the task bar and then shutting down again. No crash log is created. It apperas that only way to launch the game is from within the epic game launcher or via a desktop shortcut that calls the launcher. Adding the link the shortcut points to (com.epicgames.launcher://apps/Jaguar?action=launch&silent=true) to steam may launch the game but steam doesn't attach to the game - home streaming doesn't work, no steam overlay etc.

Steps to play Epic Games Launcher store version of Subnautica via Steam in Home streaming

EDIT: I discovered a better solution in a thread on the steam forums (though the original credit is due to shdwphnx and justin97530 on reddit)

Add subnautica.exe to Steam as an non steam game and then set -EpicPortal as a launch option in steam (right click subnautica->properties->set launch options)




The game will then launch without issues from within steam, in home streaming and steam overlay work correctly.

It is possible that this is also a bug, the epic launcher calls subnautica.exe with many more command line options related to authentication with the Epic Games Store, as detailed below (also from the same thread on the steam forums), probably for DRM purposes. Epic or Unknown Worlds might update the exe file to require those options in the future

thread on the steam forums wrote:

** HOW TO START GAME WITHOUT THE EPIC LAUNCHER ***

1. Open "%userprofile%\AppData\Local\EpicGamesLauncher\Saved\Logs\EpicGamesLauncher.log" in your favorite text editor.

2. Find the line similar to the following...
[2018.12.23-05.32.56:378][115]FCommunityPortalLaunchAppTask: Launching app 'C:/Epic Games/Subnautica/Subnautica.exe' with commandline ' -AUTH_LOGIN=unused -AUTH_PASSWORD=<an_encrypted_hash> -AUTH_TYPE=exchangecode -epicapp=Jaguar -epicenv=Prod -EpicPortal -epicusername="<your_epic_username>" -epicuserid=<an_encrypted_hash> -epiclocale=en-US'

3. Use the info there to build the command line for your new Subnautica shortcut. It should look something like this...
"C:/Epic Games/Subnautica/Subnautica.exe" -AUTH_LOGIN=unused -AUTH_PASSWORD=<an_encrypted_hash> -AUTH_TYPE=exchangecode -epicapp=Jaguar -epicenv=Prod -EpicPortal -epicusername="<your_epic_username>" -epicuserid=<an_encrypted_hash> -epiclocale=en-US


You can now use that shortcut to launch Subnautica without having the Epic Games Launcher running in the background - not even as an icon in the system tray.

***

Notes: Know that when you make the desktop shortcut, the characters you can use are limited. If your path to the game is too long, not all of this might fit into the shortcut. (My path is short, "G:\subnautica\subnautica.exe" so everything fits with 4-5 chars left. (Tip: If your path is long and you find it doesn't fit to make a shortcut, you should also be able to write a small batch file and then start game via the batch file)

Technically, what this does is start the game WITHOUT the EPIC launcher, but of course it doesn't remove the DRM. You basically pass your EPIC account/passw to the *.exe and then start the game. (The DRM/Epic account check is obviously done within the game itself, doesn't need the launcher)

Older method:

Until the developers fix this apparent bug (launching via subnautica.exe did work for a few days after the initial release of the Epic version, then it broke after an update) I have discovered a workaround to allow streaming - it's not pretty but it works for me:

One time setup:

• On the host machine create a desktop shortcut to subnautica from within the Epic Games Launcher (click the cog next to the Launch button on your library screen to show the option to create a shortcut)
• Add the Epic Games Launcher app to your steam library. (Steam->Games menu->Add a non steam game to my library)

Then every time you want to stream:

1. On the client machine or a steam link start streaming the Epic Games Launcher (you'll need a way to control a mouse pointer connected)
2. You will see a grey window (for some reason steam can't stream the contents of the epic launcher window.)
3. Minimise the window (top right)
4. You'll see the desktop of your remote host machine
5. Double click the Subnautica icon on your desktop.
6. Voila! - Subnautica launches and you can play.

0x6A7232

This, but with uPlay, is actually necessary to get the Steam Overlay (friends chat, etc) working in Tom Clancy's Rainbow Six: Siege (as it attaches itself to uPlay for whatever reason, even though it was bought in Steam).

I just made a Steam category called "Launchers" and put all my launchers in there in case I need to do this for any reason.