Mobile Game Lighting System Development: From Concept to Optimization

Realtime lighting on mobile is a constant trade-off

One dynamic Point Light with shadows in URP on an Adreno 640 costs about 1.5–2.5 ms per frame. At a target of 60 FPS, the entire frame budget is 16.6 ms, and two such sources already consume a third of it on light alone. After testing dozens of configurations, we found the sweet spot: bake everything that doesn't move and keep 1–2 realtime sources for gameplay events.

Lighting strategy for mobile GPUs

The fundamental choice is the ratio between baked and realtime light. For most mobile games, the rule is simple: bake all static lighting, minimize dynamic.

In Unity URP this means using Mixed Lighting with Subtractive or Shadowmask mode. Subtractive is faster – static shadows are baked into the lightmap, and dynamic objects cast shadows on statics via mixed light. Shadowmask is more accurate but requires an extra texture on the GPU.

Lightmap resolution is a common mistake. Texels per unit = 20 for detailed geometry and 4–8 for background environment. One giant 2048×2048 lightmap atlas per location is good. Twenty small 256×256 lightmaps are bad – that's twenty texture binds. To avoid this, we group statics into one atlas and reuse materials.

When are dynamic sources justified?

Dynamic light is needed for gameplay events: explosions, gunshots, interactive torches. Implement them with short-lived Light objects and interpolation of Range:

IEnumerator FlashLight(Light light, float intensity, float duration) {
    float elapsed = 0f;
    while (elapsed < duration) {
        light.intensity = Mathf.Lerp(intensity, 0f, elapsed / duration);
        elapsed += Time.deltaTime;
        yield return null;
    }
    light.enabled = false;
}

Such flash lights can be used without shadow casting – visually the difference is minimal, and performance is significantly better.

Limit per-object lights. In URP set Additional Lights > Per Object Limit to 1–2 for mobile presets. The default is 8 – that's a desktop value. From our experience: on Adreno 618, two realtime sources without shadows add 0.8 ms of extra GPU time.

How Light Probes work?

Characters and enemies move through baked zones and need correct ambient lighting. We place Light Probe Groups at lighting transition points: shadow entrances, torch zones, dark corridors. For large dynamic objects, LightProbeProxyVolume replaces per-probe interpolation with volumetric sampling.

Without Light Probes, a character in a dark corner looks as if standing in sunlight – the ambient from Skybox is applied without positional awareness.

Ambient Occlusion: mobile alternatives

Screen Space AO (SSAO) on mobile is a no. It's expensive and unnecessary with proper lightmaps. Alternatives:

• Baked AO in lightmaps – free at runtime, configured in Generate Lighting settings.
• Vertex AO – baked into vertex colors, sampled in shader, completely free.
• GTAO in URP 15+ – experimental, on high-end mobile GPUs acceptable with a low radius.

Godot 4: lighting in 2D

In 2D games with Godot: CanvasItemMaterial with Light Mode = Normal Map Only enables normal maps on sprites for pseudo-3D lighting without actual 3D. PointLight2D with Shadow Enabled = false is cheap. DirectionalLight2D simulates sunlight in top-down games.

Normal mapping in 2D is a powerful tool: the game looks three-dimensional but renders as flat sprites. On mobile, this is significantly cheaper than switching to 3D for visual depth.

How to profile lighting?

Unity Frame Debugger shows all draw calls related to lighting. Xcode GPU Frame Capture on iOS gives a precise breakdown of shader invocations. Targets: Shadow Map passes ≤2 per frame, Additional Lights ≤2 realtime sources simultaneously.

What is included in the lighting system development?

1. Scene and target device analysis – strategy selection (baked/realtime mix).
2. Lightmap resolution adjustment and atlas creation – eliminate resource waste.
3. Light Probes placement and Proxy Volume configuration.
4. Dynamic source optimization: Per-Object Limit, coroutine caching.
5. Profiling and finalization – Frame Debugger, GPU Capture, Instruments.
6. Documentation for the team (configs, diagrams, metrics).

Our track record: 10+ years in mobile development, 50+ projects optimized for iOS/Android. We guarantee the lighting system will fit within 16.6 ms frame budget for 60 FPS on target devices. Contact us for a consultation or estimate for your project.

Unity URP documentation: https://docs.unity3d.com/Manual/universal-render-pipeline.html

How to choose cross-platform development: Flutter, React Native, or KMM?

We often work with startups that need two apps—iOS and Android—with a budget for one team. Or corporations that want to release an internal tool in three months on both platforms. Cross-platform development solves a specific economic problem: one codebase instead of two. The question is not 'cross-platform or native'—it's 'which tool for which task.'

Each framework dictates its own stack and imposes limitations. An incorrect choice leads to rewriting the project in six months—we've seen it many times with clients who came to us after a failed first attempt. Therefore, before starting, we conduct an audit of technical requirements and team expertise. With 8+ years of cross-platform experience and 50+ delivered apps, we know the pitfalls firsthand.

The three main players now: Flutter, React Native, and Kotlin Multiplatform Mobile. They solve different problems and are poorly compared head-on. Below, we'll break down how to choose the best option for your project.

How do we choose the technology? 4 steps

1. Requirements analysis — list of native APIs, need for offline work, branded UI or standard.
2. Team assessment — expertise in Dart, JavaScript/Kotlin, availability of an iOS developer.
3. Proof-of-concept — implement a critical scenario on the chosen stack in 2–3 days.
4. Final decision — based on performance benchmarks and maintenance cost.

Case from our practice: a fintech startup needed an MVP on both platforms in 10 weeks. Their team had deep React experience, so we selected React Native. The app passed App Store and Google Play review on the first submission, and they launched on schedule. That choice saved 4 weeks compared to training for Flutter.

Comparison of Flutter and React Native: under the hood

Rendering model

Flutter renders UI independently via the Impeller engine (replaced Skia starting with version 3.10). The platform only provides a canvas—Flutter draws every pixel itself. This means:

• Pixel-perfect on all platforms. The same widget looks identical on iOS and Android—good for branded apps, bad if you need a 'native' look on each platform.
• No dependency on OS version. Material 3 in Flutter works the same on Android 8 and Android 14. System Android components are not involved.
• Platform channels for native code. Access to camera, Bluetooth, NFC—via MethodChannel or EventChannel. flutter_camera, flutter_blue_plus are wrappers over platform channels.

React Native uses native platform components. <View> on iOS is UIView. <Text> is UILabel. This means:

• Native look and feel without extra effort.
• New Architecture (Fabric + TurboModules) with JSI removed the JSON bridge between JS and native code. Synchronous calls work without serialization. This is critical for animations and gestures.
• React Native Reanimated 3 runs worklets on the UI thread—animations at 60/120 fps without blocking the JS thread.

Performance in practice

For most business apps, the performance difference between Flutter and React Native New Architecture is imperceptible. The difference appears in edge cases.

Flutter is slower when interacting with platform APIs via platform channels—each call is asynchronous, with data serialization overhead. google_maps_flutter renders the map via PlatformView—a native UIView/View embedded in the Flutter tree. Before Impeller, this caused performance issues (Hybrid Composition vs Virtual Display). With Impeller, Flutter renders UI 2–3x faster on low-end devices compared to Skia, and PlatformView performance improved by 40%.

React Native is slower in scenarios with heavy JS logic on the main thread. Parsing large JSON, complex computations—these block the JS thread and appear as UI freezes. Solution: Hermes (JS engine optimized for RN) + offloading computations to a native module or react-native-workers. With Hermes, cold start time is reduced by 30–40% compared to JavaScriptCore—that's 2x improvement on older devices.

Ecosystem and maturity

Dart is a barrier to entry for teams with a JS/TS background. It's possible to learn basic Dart in a week, but shifting your mindset to Flutter widgets and widget tree takes longer.

TypeScript in React Native is the de facto standard. A team with React experience becomes productive faster.

When to choose Flutter?

• Need a unified branded UI on all platforms (iOS, Android, Web, Desktop).
• Team is ready for Dart.
• Lots of custom animation and custom UI—Flutter is more predictable.
• The app is not tied to specific native APIs.

When to choose React Native?

• Team has React/TypeScript expertise.
• Need native look and feel.
• Heavy use of native components (Maps, Camera with native capabilities).
• Sharing code with React web via monorepo.

Kotlin Multiplatform Mobile: a different story

KMM solves not a UI problem, but the problem of business logic duplication. The concept: write business logic, networking, caching, validation once in Kotlin. iOS receives a .framework via Kotlin/Native, Android uses the library directly. UI on each platform is native.

// Shared Kotlin code — works on iOS and Android
class UserRepository(
    private val httpClient: HttpClient, // Ktor
    private val database: AppDatabase   // SQLDelight
) {
    suspend fun getUser(id: String): User {
        return database.userQueries.selectById(id).executeAsOneOrNull()
            ?: httpClient.get("$BASE_URL/users/$id").body<User>().also {
                database.userQueries.insert(it)
            }
    }
}

Ktor — HTTP client for KMM (works on iOS via Darwin engine, on Android via OkHttp). SQLDelight generates a typesafe Kotlin API for SQLite, works on both platforms.

Real limitations of KMM

Coroutines on iOS: suspend functions from shared code are called through automatically generated wrappers. SKIE (Swift/Kotlin Interface Enhancer) from Touchlab significantly improves the Swift interface: async/await instead of callbacks, AsyncStream for Flow. Without SKIE, working with coroutines from Swift is inconvenient.

Compose Multiplatform: JetBrains is developing Compose for iOS — UI in Compose works on iOS via Metal. This blurs the line with Flutter: one Compose code for both platforms. Status today: Beta, with early adopters in production (Touchlab, JetBrains own products), but stability is lower than Flutter.

Complexity of iOS integration: XCFramework from KMM module is added to an Xcode project. SPM integration exists and works. But iOS developers must understand the Kotlin API and memory management rules via Kotlin/Native (ARC + Kotlin GC work together, which is not always obvious).

When KMM is justified

The company already has mature iOS and Android teams that duplicate business logic. Switching everything to Flutter or React Native is too radical. KMM allows starting small: extract networking and models into shared code, keep UI native. Gradual migration without rewriting everything.

Typical mistakes in technology selection

Choosing Flutter "because it's a single codebase" for an app heavily reliant on native APIs (custom camera, BLE, background processing). Implementing these via platform channels adds complexity that eats up the development speed advantage.

React Native without understanding the JS thread. Heavy operations on the JS thread cause visible freezes. This is solvable, but requires understanding the architecture—otherwise the app will perform worse than native.

KMM without an iOS developer on the team. Shared Kotlin code requires an iOS engineer who integrates the framework into Xcode, writes SwiftUI on top of KMM APIs, and debugs Kotlin/Native crashes.

What is the development process and timeline?

A cross-platform project goes through the same stages as a native one: requirements audit → stack selection → design → development → testing on real devices of both platforms → publication in App Store and Google Play → support.

Testing on real devices is not optional. An emulator does not reproduce memory issues on budget Android phones and does not show differences in gesture behavior on iOS. We test 40+ scenarios on at least 5 real devices covering both OS versions.

Budget savings compared to two native teams can be up to 40–50%. The cost is calculated individually after analyzing the stack and requirements.

What's included in our work

• Technical audit and stack selection for your project.
• Architecture design (clean architecture, MVVM, BLoC/Redux).
• UI development according to design mockups for both platforms.
• Integration of native modules (camera, geolocation, push notifications).
• CI/CD setup (GitHub Actions, Codemagic).
• Testing on real devices (iOS/Android) — at least 40 scenarios.
• Preparation and publication in App Store and Google Play following guidelines (App Store Review, Google Play Policy).
• Technical support for 3 months after launch.
• Handover of source code, documentation, and access — all turnkey.

We'll evaluate your project in one day—get a consultation on stack selection. Order turnkey development and receive a cross-platform app within the agreed timeline, backed by our experience and guaranteed milestones.