EN Studio Demo Mode

Demo mode and studio-apply

Français · Type: how-to · Audience: author · Context: demo Studio · Status: ready · Applies from: 4.2.5

The local Studio · contract: stable · verified by CI (support matrix of 4.4.0, 2026-10-23): Chromium end to end (the Studio's checks); Windows: the unit suite only · automated checks: jobs e2e, windows; CI plan e2e, windows; 2 test files · people's passes: studio-hero-matrix not run (#238) · known limits: demo-limits

The Studio also runs without any server, on a static host: the demo game's Studio is online at https://wanoo.github.io/quest-n-click/studio.html, built by the CI. Your edits stay in your browser; download them as a patch and npm run studio-apply writes them into your copy of the game.

What you get

Edits made in the online demo Studio (texts, layouts, added entities, the storyboard, notes) written into your clone, through the same operations the local Studio uses.

Context and versions

The demo Studio (a static build) and the engine repository, where npm run studio-apply runs. True from 4.2.5 (the address above).

Prerequisites

• To apply a patch: the engine repository cloned and installed (Install from the repository), with the game the patch was made on.

Where to run the commands

The demo runs in your browser. npm run studio-apply and the demo build run in the engine repository, on your machine.

How the demo works

Same UI, same engine view and placement editor as the local Studio; the edits stay in the browser.

• Build. npm run build:studio-demo (that is STUDIO=1 VITE_STUDIO_DEMO=1 vite build); the CI sets both variables on its npm run build. With STUDIO=1, the build first writes public/studio-demo/snapshot.json (tools/studio/snapshot.ts, also npm run studio-snapshot; ignored by git): { game, rooms: { <id>: { def, layout, texts, file } }, storyboard, notes, docs: { CONTENT_GUIDE }, assets }, everything the Studio reads from the API. Without STUDIO=1, neither studio.html nor the snapshot reach dist/. The Studio's and the dev tools' code goes to dist/assets/tools/, outside the service worker's precache.
• Backend. src/studio/api.ts defines the Api interface; the dev server's is the default. The browser one (src/studio/api-browser.ts) is used when the build says so (VITE_STUDIO_DEMO=1) or when GET /__studio/api/game answers 404 (or a page instead of JSON). It loads the snapshot and replays the edits kept in localStorage under web-scumm.studio-demo.<game>: a list of patches { kind: 'text', room, path, value } (replace, [+] append, null delete, with the same path shifts as the room file), { kind: 'layout', room, layout }, { kind: 'entity', room, entity } (Add prop / hotspot / actor), { kind: 'storyboard', storyboard }, { kind: 'note', note }, { kind: 'note-edit', id, text, about?, edited }, { kind: 'note-delete', id }. A later layout or storyboard replaces the earlier one; editing or deleting a note added in the demo rewrites its note patch.
• Checks. Validate and Solve run in the page (src/engine/tools/validate.ts, solve.ts) on the real game module with the edits applied: layouts, added entities, and every text whose path reaches a string of the compiled room (look lines, names, hints, topics, lines of on / talk / onEnter…). Export Markdown downloads storyboard.md. No events: there is nothing on disk to watch.
• Engine view. In a demo build the dev tools load with ?edit / ?dev too (and only then: the player's game is the same). They apply the same patches to the game and the layouts at start. Save layout in the editor posts the layout to the Studio around it (postMessage, message saved with layout), which keeps it as a layout patch; the editor opened alone writes the patch to localStorage itself. On the dev server, the editor writes layout/<room>.json through the Studio's API (PUT /__studio/api/room/<id>/layout, one guarded operation of the journal); it falls back to the patch only when that API does not exist.
• Banner. "Demo: your edits stay in this browser", Download patch (studio-patch-<game>.json: { format: 'web-scumm-studio-patch', version, game, created, patches }) and Reset demo (drops every edit).

Limit · demo-limits A text the room builds with code (a shared constant, a helper) is validated only on the server version. Screenshots need the dev server: the panel is hidden. The Assets tab is read-only, the voice table, the scenario map and the semantic diff are absent, structured edits (set_value) need the dev server, and the Assistant has no screenshot, run_tests nor asset_prompts (The Assistant).

Documentation in the snapshot

Applies from 4.5.0

From 4.5.0 the snapshot also carries the wiki: a package's bundle when the engine is installed from one, otherwise the repository's ready pages (never a draft). The demo's Assistant reads them with search_docs, list_docs and read_doc by id; read_doc by name still has only CONTENT_GUIDE.

Steps

1. Edit in the demo Studio. The banner counts what you changed.

2. Download patch: you get studio-patch-<game>.json.

3. Apply it to your copy:

   # in the engine repository
   npm run studio-apply studio-patch-demo.json

   It replays the patch through the Studio core (setText, setLayout, addEntity, setStoryboard, addNote, editNote, deleteNote, in order) and prints one line per patch (✔ applied, = unchanged, ✘ failed, with the reason) and a summary: <n> applied, <n> unchanged, <n> failed (<game folder>). GAME=<id> or GAME_DIR=<folder> pick the game, as for every tool; a patch made on another game is applied with a warning (⚠ the patch was made on "<game>", the current game is "<game>").

Guarantee · apply-replays-demo · referenced · scope self-checked by the author (AI), not reviewed studio-apply writes the demo's edits into a copy of the game, which then reads back as the demo showed it.

Expected result, and how to check it

The summary says 0 failed, the exit code is 0, and git diff shows the demo's edits in the room files, the layouts, storyboard.json and notes.json. Open npm run studio to see them.

Common errors

Symptom	Cause	Fix
usage: npm run studio-apply <patch.json> (exit 2)	No file given	Give the patch file
not a Studio patch (expected { format: "web-scumm-studio-patch", patches: [...] })	Another file	Use the downloaded studio-patch-<game>.json
A line ✘ … and exit code 1	That patch failed (a room renamed, a text moved); the others still applied	Make that edit by hand in the Studio
⚠ the patch was made on "…"	GAME is another game	Set GAME=<id> to the patch's game

Files or data changed

In the browser: localStorage key web-scumm.studio-demo.<game>. In your copy: the room files, layout/*.json, storyboard.json, notes.json of the game, each patch one operation of the journal.

Recovery or going back

In the browser, Reset demo drops every edit. In your copy, the writes are ordinary files: git checkout -- games/<id>.

References

• studio-server/src/ops/apply.ts, src/studio/demo-patch.ts, src/studio/api-browser.ts.
• Play online and try the demo Studio.

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