Arc customize

LSPosed/Xposed module for applying Arc customize material overrides to the official Arcaea package (moe.low.arc) at runtime. The official APK, package name, signature, dex, resources, and native libraries are not modified.

Current MVP

• Module package: dev.arc.assets
• Target package / LSPosed scope: moe.low.arc
• Version: 0.5.1
• Asset overrides: 348
• Supported ABI: arm64-v8a, armeabi-v7a
• Runtime root: /sdcard/Android/media/moe.low.arc/ArcDark/
• Project-side current material pack: Arc_dark/packs/difference/
• Built-in selectable pack: pairumu_cat_dark (派尔姆猫_dark, 296 overrides)

The launcher UI is titled Arc customize and provides an injection switch, a current material difference count, a scrollable material pack stack, ZIP import, status summary, diagnostics copy, refresh, and Open Arcaea.

Material Packs

• difference is the project-side current material difference pack under Arc_dark/packs/difference/. It mirrors the 348 bundled override entries for project organization and is not shown as a selectable runtime pack.
• pairumu_cat_dark is bundled inside the module APK as 派尔姆猫_dark. It contains 296 same-name asset differences generated from Arcaea 6.15.0c, includes cover.jpg, and ZIP imports cannot reuse this reserved ID.

Third-party packs are imported from ZIP files. A ZIP pack must contain root-level pack.json plus files under allowed assets/ folders. Optional version, description, author, and root-level cover metadata are shown in the UI. formatVersion is the import format version; version is free-form pack display metadata.

pack.json
cover.png
assets/img/track.png
assets/img/note.png
assets/models/tap_l.png

Example pack.json:

{
  "formatVersion": 1,
  "id": "sample_pack",
  "name": "Arc Dark Sample Pack",
  "version": "1.0",
  "description": "Small import test pack generated from bundled Arc Dark assets.",
  "author": "Arc Dark",
  "cover": "cover.png",
  "Change": {
    "Default Fonts": "fonts"
  }
}

The default allowed assets/ folders are audio, char, Default Fonts, img, layout, models, particle, songs, start_up, and voice. Change maps a ZIP source folder under assets/ to the target asset folder; folders not listed in Change use their own folder name.

The module extracts imported ZIP packs in the target process to:

/sdcard/Android/media/moe.low.arc/ArcDark/packs/<packId>/

The active configuration is an ordered override stack stored as active_pack_order. Resource lookup checks enabled packs from top to bottom. If the list is empty, or no enabled pack contains a requested asset, the hook does not intercept it and Arcaea uses its original asset. The old <default> bundled row is no longer displayed or used as the default active layer.

The UI stores its local control file under dev.arc.assets. Pressing Open Arcaea sends the current control state to the target process, which persists the active state to:

/sdcard/Android/media/moe.low.arc/ArcDark/control.json

Later Arcaea restarts reuse that target-side control file.

Sample Pack

The repository root contains arc-dark-sample-pack.zip, a small import smoke-test pack generated from bundled assets. Regenerate it with:

powershell -ExecutionPolicy Bypass -File .\scripts\Generate-SamplePack.ps1

Build

powershell -ExecutionPolicy Bypass -File .\scripts\Build-Debug.ps1

The project expects Android SDK 35, NDK 27.2.12479018, and CMake 3.22.1. The build script uses the checked-in Gradle Wrapper and sets JAVA_TOOL_OPTIONS=--enable-native-access=ALL-UNNAMED because AGP's Prefab path emits restricted native-access warnings under newer JDKs.

Equivalent direct Gradle commands:

.\gradlew.bat test assembleRelease
.\gradlew.bat :app:assembleDebug

Release Signing

Release signing is optional and read from Gradle properties, local.properties, or environment variables. Do not commit keystores or passwords.

arcCustomizeStoreFile=C:\\path\\to\\release.keystore
arcCustomizeStorePassword=...
arcCustomizeKeyAlias=...
arcCustomizeKeyPassword=...

Equivalent environment variables are ARC_CUSTOMIZE_STORE_FILE, ARC_CUSTOMIZE_STORE_PASSWORD, ARC_CUSTOMIZE_KEY_ALIAS, and ARC_CUSTOMIZE_KEY_PASSWORD.

Regenerate Assets

powershell -ExecutionPolicy Bypass -File .\scripts\Generate-AssetOverrides.ps1 `
  -OriginalApk C:\path\to\original.apk `
  -FixedApk C:\path\to\modified.apk

The script writes generated metadata to app/src/main/assets/arc_overrides plus override files at the module asset root, such as app/src/main/assets/img/.... It stores only input file names and hashes in generated metadata, not local absolute paths.

Regenerate the built-in 派尔姆猫_dark pack with:

powershell -ExecutionPolicy Bypass -File .\scripts\Generate-BuiltInPack.ps1 `
  -OriginalApk C:\Users\comma\Desktop\arcaea_6.15.0c.apk `
  -FixedApk C:\Users\comma\Desktop\base.apk.1

This writes app/src/main/assets/packs/pairumu_cat_dark/ and includes only same-name assets/ files whose SHA-256 differs between the original and fixed APK. Assets present only in the fixed APK are recorded in summary metadata but excluded from the pack. The generated pack also copies C:\Users\comma\Desktop\assets\img\default_jacket_256.jpg as cover.jpg.

Runtime Notes

The module keeps the LSPosed scope at moe.low.arc. Java AssetManager.open/openFd hooks remain as a fallback, and libarcdarkhook.so hooks Cocos native calls to AAssetManager_open, AAsset_read, AAsset_getLength, and AAsset_close.

Do not restore System.load or System.loadLibrary hooks; the current route uses delayed xhook_refresh() instead.

More detail is in docs/current-technical-route-report.md.