TH08 Web

One browser tab. Two legal DAT files. One endless night.

Touhou Eiyashou ~ Imperishable Night, source-built for the Web.

Enter the endless night · Latest release · How we brought TH08 to the Web · Architecture and verification

The false moon is up, the clock is moving, and Gensokyo has found one more window: your browser.

TH08 Web brings the original Japanese TH08 version 1.00d across the browser boundary. The reconstructed C++ game code runs as WebAssembly; a small JavaScript layer handles browser file access, input, audio, saves, and the canvas. This is the game logic compiled for the Web, not a TypeScript remake or an executable running inside an emulator.

Enter the night

1. Open th08-web.pages.dev in a desktop browser. Current desktop Chrome is recommended.
2. Select th08.dat and thbgm.dat from your legally obtained TH08 installation.
3. Choose Start TH08, then click the game canvas if it does not already have keyboard focus.

The launcher copies th08.dat into volatile session memory. The much larger thbgm.dat remains a browser File and is read in small ranges as music is needed. Neither archive is bundled, transmitted, cached by the site, or stored in browser persistence.

Settings, scores, replays, backups, and snapshots are stored separately in the browser's IndexedDB storage. They survive a normal reload and remain private to that browser profile. Clearing site data for th08-web.pages.dev removes them.

Replay recording and playback are supported. Complete the original save flow by choosing a replay slot and confirming End on the name-entry screen; the saved run then appears in the title screen's Replay menu.

That is the whole ritual. There is no installer, account, upload, or server-side game session: once the static Web build arrives, the night unfolds entirely on your machine.

Prefer to keep a copy or host the page yourself? The latest GitHub Release contains a provenance-gated static build and its SHA-256 manifest. It still contains no game data; local legal DAT selection is always required. Builds from this revision use the exact nine-file layout documented below.

Choose your browser

Browser	Status	Notes
Chrome	Recommended	Best observed performance and frame pacing.
Chromium-based desktop browsers	Expected to work	Use a current version with hardware acceleration enabled.
Firefox	Supported	Automatically uses a dedicated no-readback build; preliminary hardware play now generally reports 50+ FPS.
Safari and mobile browsers	Not verified	Keyboard play, WebAssembly threads, and the current presentation path are desktop-oriented.

The game requires WebAssembly threads, SharedArrayBuffer, WebGL 2, Web Audio, and a cross-origin-isolated HTTPS page. The production site supplies the required COOP and COEP headers.

For the smoothest bullet-hell input and pacing, close heavily loaded tabs, leave browser hardware acceleration enabled, and avoid power-saving modes that throttle the display refresh rate.

Danmaku controls

Key	Action
Arrow keys	Move / navigate menus
Z	Shoot / confirm
X	Bomb / cancel
Shift	Focus movement and show the hitbox
Esc	Pause

Inside the spell circle

• The reconstructed authored C++ game and PBG archive code compile to WebAssembly with Emscripten 6.0.8.
• PROXY_TO_PTHREAD keeps the authored game loop off the browser UI thread and retains the existing startup and BGM thread structure.
• A direct WebGL 2 renderer translates the D3D8-shaped draw interface into shaders, batched vertex uploads, and browser canvas presentation.
• Chromium composites the worker-owned canvas directly. Firefox receives the same batched renderer through a main-thread WebGL proxy, avoiding its costly per-frame OffscreenCanvas snapshot readback.
• The authored DirectSound-shaped mixer feeds Web Audio while BGM data is range-read from the user-selected local file.
• Browser key events enter shared atomic state and are merged with the DirectInput-shaped polling path, preserving short key presses between frames.
• IDBFS persists only the allowlisted save paths. Retail archives stay outside persistent storage.

The implementation and its verified boundaries are documented in docs/WEB_ARCHITECTURE.md. For the complete from-zero engineering story—including the failed bring-up paths, renderer replacement, browser boundaries, correctness work, and public release—read Engineering TH08 Web.

Route status

The imperishable night is playable from title to ending. The following paths have been exercised with locally selected retail data:

• title, difficulty, team, practice, Music Room, dialogue, and result screens;
• keyboard movement, shooting, focus, bombs, score, browser-local replay recording and playback, and other browser-local saves;
• direct WebGL 2 rendering and Web Audio playback;
• a complete Lunatic Border Team Final-B route in Chromium;
• a complete Lunatic Border Team Final-B endurance route on the earlier Firefox bitmap bridge, including return through Result to the title screen;
• a separate Stage 6B practice run covering the final spell sequence;
• reload and persistence tests confirming that no DAT enters IndexedDB.

Remaining engineering work includes controlled hardware profiling and long-route endurance for the new Firefox presentation build, additional replay endurance, and browser memory-ceiling measurement. See the architecture document for the exact evidence and limitations behind each claim.

Build your own night

Requirements:

• Docker
• Python 3
• a desktop browser
• your own legal th08.dat and thbgm.dat

Build the pinned Release configuration and start the repository development server:

scripts/build-web-game.sh
python3 scripts/check-web-provenance.py --artifact build/web-dist
scripts/serve-web.py --port 8000

Open http://127.0.0.1:8000/. Do not use a generic static server for this build: Emscripten pthreads require the COOP, COEP, and CORP headers supplied by scripts/serve-web.py.

The generated deployment directory contains exactly nine allowlisted files:

_headers
_redirects
th08-web.html
th08-web.js
th08-web.wasm
th08-web-firefox.html
th08-web-firefox.js
th08-web-firefox.wasm
th08-web-icon.png

Any extra file, missing file, symbolic link, executable, retail archive, or common archive container causes the provenance check to fail.

Release boundary

Cloudflare Pages hosts the public static build because it applies the checked-in _headers policy required by WebAssembly threads. Bare GitHub Pages hosting is not used because it cannot attach the repository-defined isolation headers.

Pushes to main run the following release chain:

1. repository-owned validation;
2. the digest-pinned Emscripten Release build;
3. the exact deployment-boundary check;
4. Cloudflare Pages Direct Upload.

The workflow is defined in deploy-web.yml. It requires these GitHub repository secrets:

• CLOUDFLARE_ACCOUNT_ID
• CLOUDFLARE_API_TOKEN, scoped to Account → Cloudflare Pages → Edit

Pull requests do not deploy and do not receive these secrets.

Tagged GitHub Releases attach a compressed nine-file static artifact plus a SHA-256 manifest. Release archives are for self-hosting and offline retention; they do not include retail data and still require a host that supplies the staged isolation headers.

Build and package a tagged artifact locally with:

scripts/build-web-game.sh
scripts/package-web-release.sh v0.1.0

For an authorized manual deployment:

export CLOUDFLARE_ACCOUNT_ID=<account-id>
export CLOUDFLARE_API_TOKEN=<token-with-pages-edit>
npx wrangler@4.125.0 pages deploy build/web-dist --project-name=th08-web --branch=main

Never write deployment credentials into this repository or command logs.

Map of the boundary

Path	Purpose
src/	Reconstructed authored game code and modern host adapters
src/modern/web/	Browser launcher, Web compatibility boundary, and Pages metadata
scripts/build-web-game.sh	Digest-pinned Emscripten Release build and exact staging
scripts/package-web-release.sh	Deterministic nine-file release archive and SHA-256 manifest
scripts/check-web-provenance.py	Retail-data and exact-artifact deployment gate
scripts/serve-web.py	Local server with cross-origin-isolation headers
docs/WEB_PORTING.md	From-zero engineering narrative and reproducible porting method
docs/WEB_ARCHITECTURE.md	Architecture, provenance model, and observed verification
.github/workflows/deploy-web.yml	Validated main deployment to Cloudflare Pages

Credits

Touhou Project and 東方永夜抄 ～ Imperishable Night are works of Team Shanghai Alice / ZUN. This project is unofficial and is not affiliated with or endorsed by Team Shanghai Alice.

This repository is the Web-focused fork of our source reconstruction, N0zoM1z0/th08. Its authored C++ game code is the foundation beneath the browser boundary, and its contributor authorship and commit history remain intact here.

The Web icon is project-owned artwork carried over from the modern port. It is not extracted from the retail executable or archives.

License

Repository code and documentation are provided under the included MIT License. That license does not grant rights to the original game, executable, DAT files, music, dialogue, graphics, or other retail content.