SBaGenX Android

Separate Android frontend for sbagenxlib, built with React Native and a Kotlin/JNI native bridge.

Current milestone

The repo is scaffolded as a plain React Native app and already includes:

• a vendored sbagenxlib snapshot in native/sbagenxlib/
• an Android NDK/CMake build that compiles libsbagenxbridge.so
• a Kotlin React Native module that calls into JNI
• a first editor workbench screen for .sbg and .sbgf text
• real sbx_version(), sbx_api_version(), sbx_validate_sbg_text(), and sbx_validate_sbgf_text() calls
• .sbgf curve metadata inspection during validation, including solve-backed parameter values after native prepare
• a persistent native SbxContext for .sbg documents
• preview rendering of PCM float samples from JNI without audio output
• live Android playback for .sbg via AudioTrack
• safe -SE preamble handling during .sbg prepare/playback
• runtime mix support for .sbg -m inputs and program-mode mixes resolved from bundled app assets, file paths, or content:// URIs
• native stdio-backed mix inputs via sbx_mix_input_create_stdio(...) for WAV/raw, FLAC, OGG, and MP3 using bundled Android codec archives
• SBAGEN_LOOPER override state for loaded mixes, with Android keeping mix/looper settings outside the edited .sbg text
• app-local draft save/load inside Android app storage

What is not implemented yet:

• system document picker / external file open-save flow
• .sbgf beat preview and runtime playback
• export workflows
• iOS native bridge parity

Local toolchain

• Node 22.x via nvm
• Java 17
• Android SDK with NDK support

Example shell setup:

source ~/.nvm/nvm.sh
nvm use 22

Run the app

Start Metro:

npm start

In another terminal, build and deploy Android:

source ~/.nvm/nvm.sh
nvm use 22
npm run android

To build the Android app without deploying:

cd android
./gradlew :app:assembleDebug

Repo layout

• src/: React Native UI and JS bridge wrappers
• android/: Android app, Kotlin native module registration, Gradle config
• native/jni/: JNI and CMake entry point
• native/sbagenxlib/: vendored engine snapshot for Android bring-up
• docs/: Android-specific notes

Bridge surface today

• getBridgeInfo()
• validateSbg(text, sourceName)
• validateSbgf(text, sourceName)
• prepareSbgContext(text, sourceName, mixPathOverride?, mixLooperSpec?)
• getContextState()
• renderPreview(frameCount, sampleValueCount)
• resetContext()
• startPlayback(text, sourceName, mixPathOverride?, mixLooperSpec?)
• stopPlayback()
• getPlaybackState()
• listDocuments()
• saveDocument(name, text)
• loadDocument(name)

The current editor workbench can validate both .sbg and .sbgf, inspect prepared .sbgf curve parameters from sbagenxlib, save drafts locally, prepare a persistent native render context for .sbg, preview rendered PCM samples, and start or stop live playback through the Android audio stack. Mix playback now prefers sbx_mix_input_create_stdio(...), using bundled native codec archives for OGG, MP3, and FLAC.

Bundled Android app assets now include:

• river1.ogg
• river2.ogg

That means desktop-style examples such as -SE -m river1.ogg can resolve inside the Android app without needing an external document picker first.

The parent SBaGenX repo now includes android-build-libs.sh, which rebuilds the Android libogg, Tremor libvorbisidec, and libmad static archives with the Android NDK and drops them into SBaGenX/libs/ for vendoring into this repo.

Codec vendoring is documented separately in android-codecs.md. The rule is to build codec archives from a pinned parent SBaGenX revision, then vendor snapshot copies into this repo rather than depending on a live sibling checkout.

Snapshot provenance

The vendored sbagenxlib sources and Android codec archives in this repo are currently pinned to parent SBaGenX tag v3.9.0-alpha.6 at commit 8b54e356feb2ea34d7519a4af8d4927925079f96.

See SNAPSHOT.md, android-native-bridge.md, and android-codecs.md for details.