Atman

A small 3D game about Advaita Vedānta: the teaching that the self (Ātman) is the absolute (Brahman), and that liberation (mokṣa) is a recognition, not a reward. Atman runs on Strata, a small C++ engine.

You wake in a river village with a body, a name and a list of chores. At dusk a snake on the path turns out to be a rope. The potter's pots turn out to be clay. Chapter by chapter, the things you took to be "you" are examined the way the Upaniṣads examine them, and the game's own interface comes apart. At the end nothing rolls credits. You are still in the village, still doing the chores, and nothing is at stake.

Status: the MVP is complete (milestones M0 to M7), and chapter 3, Three States, has been added since. Play it in a browser at atman.play.danielstephenson.dev, on a computer or a phone (docs/WEB.md), or download it for Windows or Linux from the releases page. You can walk the valley in first person: the village, the well, the potter's yard, the ghat and the bird tree, from late afternoon through sunset into night, with the sun where it really is over the middle Ganges plain on the spring equinox. The HUD shows the time, the body's needs, your standing and the day's chores.

At dusk the first teaching begins, The Rope. Three snakes lie on the path between the village and the ghat. A fear meter rises as you come near one, and you cannot bring yourself to walk up to it. Light the lamp (F), go as close as you dare and look at it steadily for about two seconds: it is a rope, and it stays a rope. Nothing is scored. After the last one the fear meter leaves the HUD and does not come back.

The second teaching, Clay and Pots, is at the potter's wheel. Throw a water jar, a bowl, a cup or a lamp (1–4), give it a name, and it goes on the drying board and into your list of things made. After three pots you have the clay lens (C): pots, bricks, roof tiles and the riverbank all show as one material, and the list reads "Rice for Amma: clay". Motes of light hang over the board. They were there before the first pot, and a pot only hides the ones inside it. Break one (B) and its name leaves the list, while not one mote moves.

The day has its chores, as an ordinary game would: carry water from the ghat to the potter's door, and dig clay on the riverbank north of the ghat for the wheel (E to fill, give, dig and leave). Each earns standing in the village. Drink at the well, eat at home, and at night sleep at your door (E): the screen goes dark and you wake at half past six the next morning, with the chores on the list again.

The night after the rope and the clay, the third teaching, Three States, comes in sleep. You dream the valley: the same houses and paths in an evening light, except that the sun runs backwards and every place wears the next one's name, and nothing on the HUD finds that strange ("Nothing here seems strange"); under it, a quieter line says there is nothing to do and the dream passes by itself. After a minute and a quarter the dream goes out, and deep sleep is a black screen with only the river, a dim point that slowly breathes, and one faint line: "Deep sleep. Morning comes by itself." Then you wake, and two pages of the codex are open: Yājñavalkya on the dream, and the fourth, what was there through waking, dream and deep sleep.

The morning after the deep sleep is the after-mode, and it does not end. The chores come round again and earn nothing; Standing is gone from the HUD. Press V to step out of the body: the avatar carries on alone, drinking, eating, carrying water and clay, sitting on the ghat steps, going home at dusk, while you fly anywhere in the valley. V again steps back in. That morning the game says the teachings are done and nothing more is asked of you, and the drone of a tanpura comes in under the valley's sounds; nothing says the game is won. The days after are not all alike: the second evening the village sets small clay lamps along the ghat steps and floats more on the river (the morning says so), the third morning a flock of egrets crosses the valley, and after that each comes round now and then.

Until then the HUD's NEXT line says what comes next, and the names of houses and places show over them as you near them: your door is indigo, the potter's ochre, the shrine's saffron under a saffron pennant. After sunset each house lights a lamp by its door.

Every sound is made by the game as it plays, with no recordings: the river, the wind, birds and a koel by day, crickets at night, footsteps on earth and on the ghat's stone, the wheel, a heartbeat while there is fear, a bell for each new page of the codex, and the shrine's low bell each evening as the sun goes down. M (or the page's Sound button) turns it off.

The codex (Tab) holds each verse the game has taught, as a page with the Sanskrit in Devanagari and IAST, an English translation, the translator, the edition and the sources. A page opens when its teaching happens: the rope and the snake (Gauḍapāda's Māṇḍūkya Kārikā 2.17–2.18), clay and its names (Chāndogya Upaniṣad 6.1.4), the space in the pot (Kārikā 3.3–3.4), the dream (Bṛhadāraṇyaka Upaniṣad 4.3.9–10 and 4.3.14) and the fourth (Māṇḍūkya Upaniṣad 2 and 7). One page is open from the start: how Advaita, Viśiṣṭādvaita and Dvaita each read tat tvam asi. The game pauses while the codex is open.

The well, at a quarter to five	The ghat steps down to the river

The village from the ghat	Sunset over the river, just after six

Lamplight on a snake at half past seven	It was a rope

Throwing a water jar	Three pots, three names

Through the clay lens	The jar broken, the space unmoved

The codex: the rope and the snake	Other schools

The dream, at a quarter to six	Later in the dream: the sun back in the afternoon

The codex: the dream	The codex: the fourth

The next morning	Watching the avatar go about its day

A lamp night, the second evening	Egrets, the third morning

Frames from the game's own headless tour (atman --headless --tour --frames DIR).

Build and play

Atman builds with CMake 3.24 or newer and a C++17 compiler. Strata, and the SDL3 it uses, are fetched and built along with it, at the commit ATMAN_STRATA_REF in CMakeLists.txt pins (Strata v0.7.0).

cmake -S . -B build
cmake --build build --config Release
./build/atman               # Windows: build\Release\atman.exe
ctest --test-dir build -C Release

On Windows, tools/play-atman.bat does all of this in one step. It installs CMake and the Visual Studio C++ build tools with winget if they are missing, clones or updates main into %USERPROFILE%\atman-play, builds the game and starts it. Extra arguments go to the game, for example play-atman.bat --tour, or play-atman.bat --autopilot --speed 10 to watch the autopilot play the whole slice at ten times speed.

The game continues from its save: %APPDATA%\Atman\default on Windows, ~/.local/share/atman/default elsewhere, or --slot DIR. It saves every two minutes, on F5 and on quit, and keeps the save before last. A save that fails its checksum is refused with a message and the previous one loads. --new starts over (the old save is kept as the previous one). --autopilot never saves. A second village (F6) is saved beside the first, in default-2 (or DIR-2); the settings (text size, captions, which village) are in the first's settings.txt.

On Linux, SDL3 needs the X11 development packages (libx11-dev libxext-dev libxcursor-dev libxi-dev libxfixes-dev libxrandr-dev libxss-dev). cmake -DATMAN_WITH_STRATA=OFF builds only the simulation and its tests, with no engine.

Input	Action
Mouse	Look
W A S D	Walk
Shift	Hurry
E	Use what is here: fill the jar, give the water, dig or leave clay, drink, eat, sleep
F	Light the lamp, or put it out
1 2 3 4	At the wheel: throw a water jar, a bowl, a cup or a lamp, then type its name and press Enter
B	Break the pot you are looking at
C	The clay lens (after three pots)
Tab	The codex (Up and Down, or W and S, choose a page; Tab or Esc goes back)
V	In the after-mode: step out and watch the avatar (W A S D and the mouse fly), or step back in
M	Sound on or off
F1	Show or hide the controls
H	Hide or show the HUD, to see the valley
F2	Text size: normal, large, larger
F3	Captions for the sounds that matter (a heartbeat when afraid, the wheel, the river in deep sleep); they also show while the sound is off
F6	Your other village: the game keeps two, each with its own save
F5 / F9	Save now / load the last save
Esc	Free the mouse (Esc again quits)

Documents

Document	What it covers
CONCEPT.md	The game: the design problem, the valley, each chapter's teaching and mechanic, teaching rules, tone
MVP.md	The first playable slice, what "done" means for it, and the milestones
ARCHITECTURE.md	Code layout, the simulation core, how each mechanic maps to Strata, text, saves, tests
RESEARCH.md	Sources: Upaniṣads, Śaṅkara and later Advaita, modern scholarship, Alan Watts and other modern teachers, related games, and a verification log
docs/REVIEW.md	The review packet: every codex page's Sanskrit and English, word-by-word glosses of the working translations, questions for a reviewer, how to send feedback, and the checks that need real hardware
docs/WEB.md	The browser build: what differs from the desktop game, touch controls, saves in the browser, building it, CI and deployment
docs/RELEASING.md	Cutting a release: the version, playtest evidence and the Windows and Linux downloads
docs/playtests/	Playtest notes for each release, and what was changed for them
docs/THIRD-PARTY.md

Approach to the teaching

• The doctrine follows classical Advaita as taught by Śaṅkara and the Upaniṣads he commented on.
• Modern voices such as Alan Watts, Swami Vivekananda and Ramana Maharshi shape the tone, and the game labels them as later readings.
• Other Vedānta schools (Viśiṣṭādvaita, Dvaita) read the same verses differently, and the game says so.
• Every verse shown in the game is cited with its source, verse number and translator.
• The game never awards a score or achievement for liberation.
• An academic and a teacher from a living Advaita lineage review the game before a build is published.

Corrections from people who know this tradition are welcome as issues.

Checking the docs

python3 tools/check_docs.py checks that every relative link and heading anchor resolves, and that every citation ID (such as [P1]) is defined in RESEARCH.md. CI runs it on every pull request.

The codex plates

Strata draws ASCII text only, so each codex page is an image ("plate") made ahead of time from content/codex/*.json and committed under content/plates/. After changing an entry, run python3 tools/plates/make_plates.py (it needs Pillow built with libraqm, for Devanagari shaping). python3 tools/plates/make_plates.py --check needs nothing beyond Python. It checks that every citation is defined, every entry names a translator, and every plate is current. CI runs it.

License

MIT. The plates are set in Tiro Devanagari Sanskrit, under the SIL Open Font License (tools/plates/fonts/OFL.txt). The game decodes them with stb_image (public domain or MIT, third_party/stb/), and plays sound through miniaudio 0.11.25 (public domain or MIT No Attribution, third_party/miniaudio/).