Brings back 2-player splitscreen (top/bottom) in ARK: Survival Evolved on Steam PC. The console versions have splitscreen; the PC game still contains that code, but it is switched off and broken. This mod is a small DLL that switches it back on and fixes what breaks.

Single-player only. Never use it on official or BattlEye-protected servers.

Click the image to watch the demo on YouTube.

How this was made: all of the code, the reverse engineering and the analysis tools were written by Claude (Anthropic's AI model), working in Claude Code. I tested every change in-game and found what needed fixing by playtesting, giving Claude notes on each bug (what happened, when, and screenshots) until it worked.

• ARK: Survival Evolved on Steam, preaquatica beta branch, version 358.26 (build 19239750). The DLL checks every spot it patches first; on any other game version it skips its fixes (and says so in its log) and only passes controller input through.
• A controller for player 2 (XInput, e.g. an Xbox controller). Player 1 can use mouse and keyboard or controller 1.
• Launch the game without BattlEye.

1. Back up ARK\ShooterGame\Saved\LocalProfiles and ARK\ShooterGame\Saved\SavedArksLocal.
2. Download the latest release and copy xinput1_3.dll and ArkSplitscreen.ini into ARK\ShooterGame\Binaries\Win64\.
3. Open ARK\ShooterGame\Saved\Config\WindowsNoEditor\Engine.ini and add:

   [/Script/EngineSettings.GameMapsSettings]
   bUseSplitscreen=True
   

4. Start the game without BattlEye and load a single-player world.
5. Once player 1 has spawned, press Menu/Start on controller 2 to join. Player 2 gets their own character and save.

Delete xinput1_3.dll, ArkSplitscreen.ini and ArkSplitscreen.log from Binaries\Win64, and remove the two lines from Engine.ini.

Joining and saves

• Player 2 can join without crashing (they get a stable id derived from player 1's).
• Player 2 has their own save file, so no character takeover, black screen or respawn loop. The same two players always get the same characters back.

Per-player HUD

• Each player gets their own HUD, hotbar, notifications and banners in their half of the screen; HUDs are rebuilt when someone joins or leaves.
• Controller button hints for player 2, readable radial (hold-E / whistle) menus, correctly sized tooltips, item thumbnails and hotbar.
• Dino name labels show for each player separately (before, both players had to be near the dino).

Pause menu

• Player 1: Teleport to Player 2.
• Player 2: Teleport to Player 1 and Swap Screens (swaps which half each player is in, HUD included).

Graphics

• Fixes the black lighting and the very dark shadows on player 2's half.
• Fixes black textures when the players are far apart.

World

• The world (rocks, foliage, terrain) loads around both players, so you can play far apart; no tether needed.
• The PvP respawn timer is turned off while two players are in.
• Players can target each other, so "hold to invite to tribe" works.

Controls and sound

• Each player keeps their own first/third-person camera; player 2's triggers in the inventory no longer switch player 1's camera.
• Player 2's character sounds (grunts, tool swings) are no longer muffled.

ArkSplitscreen.ini (next to the DLL) has comments for every option: HUD and hotbar size, tooltip and radial-menu text size, the graphics fixes, and optional render settings applied only during splitscreen (e.g. a lower r.ScreenPercentage for frame rate). The DLL writes ArkSplitscreen.log next to itself; include it when reporting a problem.

• 2 players only; the game's console code caps splitscreen at two.
• Top/bottom only; ARK's HUD layout code doesn't support side-by-side.
• Single-player only; online and listen-server play are untested.
• Only the version listed above. A game update will need an updated DLL.

Tested:

• Playing on The Island, with both players together and with one player spawned far away from the other. That test found the vanishing rocks and foliage and led to the world streaming fix.
• Beginner engrams such as the harvesting tools and the spear, plus a thatch floor, a campfire and tribe invites.
• Taming a dino with player 2 works, with one known quirk (below).

Known issue: when player 2 finishes a tame, the "name your dino" box opens on player 1's half and only player 1 can type in it (name it with player 1's keyboard). The console version reportedly behaves the same way.

Known issue: after a player dies and respawns far away from the other, the very dark shadows can come back on one half of the screen (and move with that spot if a player teleports there).

Not tested yet (bug reports welcome):

• Maps other than The Island.
• One player going into a cave while the other stays outside.
• Transferring characters to other maps.
• Riding dinos.
• Later engrams and items. Only beginner ones have been tried, so some later ones may still have splitscreen bugs.
• Unofficial servers. Not tested and not planned; the mod is meant for single-player.

xinput1_3.dll is a proxy for the controller DLL the game loads: it forwards all controller calls to Windows' own xinput1_3.dll and patches the game in memory (inline hooks and small code patches). How each problem was found, with addresses: notes/status.md and notes/symbol-findings.md.

Run build.bat (needs Visual Studio 2019 with the C++ desktop workload). Output: build\xinput1_3.dll.

tools\ has the read-only analysis scripts used to find all this: pdb_dump.py (symbols to a TSV), disasm.py, xrefs.py, refs.py, writes.py, vtable.py, prologues.py, imports.py, dump_modules.py. They need Python 3 and capstone. renderdoc\scripts\ has the RenderDoc analysis scripts used for the graphics fixes (run with qrenderdoc.exe --python <script> started from the repo folder; they read and write captures\, or the folder in the ARK_CAPTURES environment variable).

MIT, see LICENSE. This covers the mod's own code and notes only, not ARK or any of its files.

Unofficial fan project, not affiliated with or endorsed by Studio Wildcard or Snail Games. Use at your own risk and keep backups of your saves.