Schwert und Magie on Pebble

A port of the classic German C64 text-adventure RPG series Schwert und Magie (German Design Group, 1989–1992) to the Pebble Time 2 smartwatch.

Architecture

The phone runs VICE 3.8 as a companion app and streams the C64 text screen to the watch. Button presses on the watch flow back to VICE via Bluetooth.

The game

Schwert und Magie is an 8-episode text-adventure / RPG series for the Commodore 64, published in German by boeder-Verlag. Two episodes share one disk:

Disk	Episodes
I	Folge 1: Das geheimnisvolle Kraut · Folge 2: Der unheimliche Tempel
II	Folge 3: Das Piratenhaus · Folge 4: Die Burg des Magiers
III	Folge 5: Das Haus des Vampirs · Folge 6: Der Turm des Todes
IV	Folge 7: Unter Wasser · Folge 8: Insel der Wunder

The copy-protection scheme asks for a word from the printed Anleitung (manual). The app includes the full manual text with a look-up button (📖) so you can answer the prompt without keeping the paper around.

Repository layout

SchwertUndMagieOnPebbleWatchApp/      Pebble watchapp (C + PebbleKit JS)
SchwertUndMagieOnPebbleCompanionApp/  Android companion app (Kotlin + NDK)
versions/                             Original .d64 disk images (4 disks)
docs/                                 Architecture notes and diagrams
build-image/                          Dockerfile for the release build environment
dist/                                 Build artifacts (gitignored) — see dist.sh

Run ./dist.sh to build release artifacts for both apps in one step: dist/schwert-und-magie-<version>.{aab,apk,pbw} — the signed Android AAB (Play Store), APK (sideload), and Pebble .pbw (Rebble / direct install). Requires the Android release keystore to already be configured (docs/publish.md §2.1-2.3). The version comes from the current git tag by default (git tag v1.2.3); see docs/publish.md §4 for pushing that tag to trigger an automated, containerized build via Gitea Actions instead.

How it works

Three processes cooperate across two devices:

Pebble watch
  │  Bluetooth AppMessage
  ▼
Core for Pebble (on phone) — PebbleKit JS bridge
  │  HTTP on 127.0.0.1:8888
  ▼
Android companion app — NanoHTTPD server
  │  JNI
  ▼
VICE 3.8 (C64 emulator, cross-compiled for ARM64/x86_64)

The watch displays the C64 text screen (40×25 cells) in a scroll view and provides a key wheel for the number keys most used by the game. The companion app renders VICE's 320×200 framebuffer on-screen and also provides a virtual C64 keyboard for direct input.

See docs/architecture.md for the full design.

Requirements

• Android phone running Android 7.0+ (API 24)
• Pebble Time 2 (or any Pebble running firmware 3.x — the .pbw targets all SDK 3 platforms)
• Core for Pebble installed on the phone (the community Pebble app)
• C64 ROM files — kernal, basic, chargen, 1541 — legally obtained from your own C64 or from Cloanto's C64 Forever. The app prompts you to import them on first launch; they are never bundled.
• Disk images — .d64 or .g64 files for the four game disks. You can import your own or use the in-app Fetch Disks button to download community-preserved dumps from the Internet Archive's C64 Preservation Project (requires nibtools, which is cross-compiled automatically).

Building

Android companion app

cd SchwertUndMagieOnPebbleCompanionApp
./gradlew assembleDebug        # debug build
./gradlew assembleRelease      # signed release build (requires keystore.properties)
./gradlew installDebug         # build + install on connected device

VICE 3.8 and nibtools are cross-compiled automatically the first time — the Gradle buildVice and buildNibtools tasks unpack the source tarballs from res/ and build libvice.a / libnibtools.a for ARM64 and x86_64. The NDK must be installed (Android Studio → SDK Manager → SDK Tools → NDK (Side by side)).

Pebble watch app

cd SchwertUndMagieOnPebbleWatchApp
pebble build
pebble install --phone <phone-ip>

In headless / CI environments add --vnc to every emulator command.

Getting disk images onto the device

Option A — Fetch Disks button (in-app)
Opens a dialog, downloads all 8 episode disks as .nbz files from the Internet Archive C64 Preservation Project, and converts them to G64 using nibtools. Requires a network connection; conversion runs on-device.

Option B — manual copy
Copy .d64 or .g64 files to the app's external files directory via USB or adb push, matching the names expected by the drawer (e.g. SCHWUM1A.D64).

Hero saves

Hero characters are stored on separate hero disks (up to 3 slots). The app manages these from the drawer — create a new hero disk, load an episode disk, then swap to the hero disk when the game asks for it. A built-in stat editor lets you inspect and edit a saved hero's attributes directly.

Save states

The 💾 button saves or restores a full VICE snapshot (CPU registers, RAM, VICII, SID, CIA) to one of three slots. Snapshots go through a CPU trap to ensure register consistency — see docs/architecture.md §4.4.

Publishing

See docs/publish.md for keystore setup, Google Play, F-Droid, and Rebble submission.

Automated releases (Gitea Actions)

Pushing a tag vX.Y.Z builds both apps in a containerized runner and publishes a Gitea Release with the versioned artifacts attached — see docs/publish.md §4. One-time setup:

1. Build the build environment image locally and push it (./build-image.sh then ./upload-image.sh, needs registry.env — copy from registry.env.example). Use ./run-image.sh in between to sanity-check the image before pushing.

2. Register a self-hosted act_runner with a Docker executor.

3. Add repo secrets under Settings → Actions → Secrets:

   Secret	Value
   RELEASE_KEYSTORE_B64	base64 -w0 SchwertUndMagieOnPebbleCompanionApp/release.keystore
   RELEASE_KEYSTORE_PROPERTIES	full contents of SchwertUndMagieOnPebbleCompanionApp/keystore.properties
   REGISTRY_USER / REGISTRY_PASSWORD	same as in registry.env, so the runner can pull the private build image

   GITEA_TOKEN is injected automatically per job — nothing to add for it.

4. git tag v1.2.3 && git push origin v1.2.3.

Full details, including runner registration commands, are in docs/publish.md §4.

License

The watch app and companion app source code in this repository are released under the MIT License.

The Schwert und Magie game content (disk images, manual text) remains the property of its original authors and is not part of this license. VICE and nibtools are GPLv2 and are built from source at compile time; their source tarballs in res/ are not covered by this repository's MIT license.