bgclock/public_html/README.md

# Backgammon Clock

A two-player match clock with **simple delay you can actually see**. Reserve time
plus a fixed number of free seconds each turn that never carry over — the
Backgammon Galaxy control. Defaults to 3:00 + 15s.

Plain HTML, CSS and JavaScript. No frameworks, no fonts, no images, no network.

## Getting it onto your phone

Chrome will only offer a real install over HTTPS, so the file needs a host.
GitHub Pages is free and takes about two minutes:

1. Create a new public repository, e.g. `bgclock`.
2. Upload all six files to the root: `index.html`, `manifest.webmanifest`,
   `sw.js`, `icon-192.png`, `icon-512.png`, `icon-maskable-512.png`.
3. **Settings → Pages → Source: Deploy from a branch → `main` / `(root)` → Save.**
4. Wait a minute, then open `https://<you>.github.io/bgclock/` on your phone.
5. **Android, Chrome:** menu (⋮) → **Add to Home screen** → **Install**.
   **iOS, Safari:** Share (□↑) → **Add to Home Screen** → **Add**. It has to be
   Safari — Chrome and Firefox on iOS can't install a web app.

Open it from the home-screen icon and it runs fullscreen with no browser
chrome, offline, with the screen kept awake while a game is on.

On iOS a few things behave differently, none of them fatal:

- **Install from Safari, and play from the home-screen icon.** In a Safari tab
  you lose a strip of the screen to the toolbar, and iOS clears the saved
  settings of a site you haven't visited for a week. The installed app keeps
  its own storage and doesn't get pruned that way.
- **There's no vibration** — iOS gives web pages no haptics at all, so the
  turn-change buzz is silent there. The sounds still play.
- **The ringer switch doesn't mute the clock.** The page claims a playback
  audio session so you can hear the delay tick with the phone silenced, which
  in exchange pauses any music you had going. If you'd rather keep the music,
  delete the `navigator.audioSession` line in `index.html`.
- **Screen wake needs iOS 16.4 or newer.** Below that the screen dims on its
  usual schedule mid-game.

If you're using a different path than `/bgclock/`, edit the `"id"` field in
`manifest.webmanifest` to match, or just delete that line.

To try it before hosting, open `index.html` in any browser — everything works
except installation and the service worker.

## Using it

- **Tap your own half** to end your turn and start your opponent's clock.
  At the start, whoever taps first sets the *other* player going.
- The waiting player's taps are ignored, so a stray hand won't stop the clock.
- The bar under the big time is the delay draining. When it empties you get a
  soft tick and your reserve starts moving. That's the moment worth hearing.
- **Reset** returns to the starting position. It takes two taps: the first arms
  the button — it lights up and a ring unwinds around it — and a second tap
  within those two seconds does it. One stray thumb can't wipe a live game.
- **Pause** freezes mid-turn and resumes exactly where it stopped, delay
  included. Opening settings pauses automatically, and leaves it paused so the
  clock only restarts when both players are ready.

Backgammon clocks pause between games, and after a cocked die the delay is
normally restarted — use pause and reset for those.

## Settings

At the top of the sheet are three presets — **2m / 12s**, **3m / 12s** and
**3m / 15s**. Tapping one jumps both timers there and lights it up. Change the
time or delay by hand and the highlight goes out; land back on a preset's
numbers and it comes back on.

| Setting | Range | Default |
| --- | --- | --- |
| Time | 0:15 – 99:00 | 3:00 |
| Delay | 0 – 60 s | 15 s |
| Colour | Sage, Brass, Slate, Teal, Plum | Sage |
| Sound | on / off | on |

Brass is the colour in the chess.com app, if you want the exact original look.
Changing time or delay resets the clock. Settings are kept in `localStorage`, so
they survive closing the tab, force-quitting the installed app and rebooting the
phone — the app also asks for persistent storage so they aren't evicted when the
device runs low on space (Chrome honours that request; Safari ignores it). Only
the settings are stored; a game in progress isn't.

## Sounds

All three are generated with the Web Audio API, so there are no audio files to
download and nothing to attribute.

- **Turn change** — a soft rising fifth with an octave partial, marimba-like.
- **Delay expiry** — a single quiet 300 Hz tick, deliberately easy to miss unless
  you're listening for it.
- **Time out** — a falling triad, loud and unambiguous.

## Licence

Do whatever you like with it.