RuntimeConfig

RuntimeConfig is the immutable session configuration: created once, effective for the entire session. Changing any field requires building a new config and re-creating the session. Construction must go through Builder.

Directories and displayDensity

The Builder has two entry points:

new RuntimeConfig.Builder(Context)                          // cacheDir/filesDir/displayDensity derived from the Context
new RuntimeConfig.Builder(cacheDir, filesDir, density)      // fully caller-supplied, no Context

Field	Description
cacheDir	Cache directory; the system may clear it
filesDir	Persistent directory; the system will not clear it
codeCacheDir	JS bytecode cache directory; derived from cacheDir by default (system-clearable), overridden by setCodeCacheDir
workersPath	Worker script directory; may be null
displayDensity	Pixel density, the CSS px conversion base; must be a real value when using the three-parameter Builder

If the host has its own game-package or cache directory conventions, use the three-parameter Builder — take the two root directories yourself and do not let the SDK pick them for you.

Rendering cadence

Field	Default	Description
targetFps	60	The ceiling the engine uses to drive requestAnimationFrame — a ceiling, not a guarantee
immersiveMode	true	Full-screen immersive mode
startupOrientation	null	Must be "landscape", "portrait", or null; any other value throws IllegalArgumentException immediately

Debug and watchdog

Field	Default	Description
debugEnabled	false	Attaches DebugOverlay and Console log view
logLevel	WARN	TRACE / DEBUG / INFO / WARN / ERROR / OFF
watchdogEnabled	true	Reports heartbeat timeouts to the native side
watchdogTimeoutSecs	10	Number of seconds tolerated without a heartbeat

Do not disable the watchdog in production builds — it is the only mechanism at the engine level that can raise a signal before the system ANR fires.

Code signing

Field	Default	Description
codeSigningEnabled	true	Signature verification is on by default; do not mistake this for a debug toggle
codeSigningPubkey	null	Hex Ed25519 public key, 64 characters

A common mistake is assuming signature verification defaults to off in production builds — it is the opposite: it defaults to on, and without a pubkey the verification rejects content outright. Production configuration = set both fields. To skip verification during debugging = explicitly call setCodeSigningEnabled(false), and treat it as a temporary measure only.

Content-side injection

Two list fields that exist only on the Builder; both are passed to native over JNI as JSON:

• subPackages: List<String[]>, each entry {"name","root"} — sub-package local mount plan;
• preludeScripts: List<String[]>, each entry {"name","source"} — complete script source to run before game.js, used to inject polyfills; executed in list order.

Builder overview

RuntimeConfig config = new RuntimeConfig.Builder(context)
    .setCodeCacheDir(customCodeCache)
    .setTargetFps(60)
    .setStartupOrientation("landscape")
    .setDebugEnabled(BuildConfig.DEBUG)
    .setLogLevel(RuntimeConfig.LogLevel.WARN)
    .setImmersiveMode(true)
    .setWatchdogEnabled(true)
    .setWatchdogTimeoutSecs(10)
    .setCodeSigningEnabled(true)
    .setCodeSigningPubkey(pubkeyHex)
    .setWorkersPath(workersDir)
    .build();