Building cross-platform XR applications

1. Core Strategies for Cross-Platform XR

A. Engine Selection

Engine	Cross-Platform Support	Best For
Unity	25+ XR platforms via XR SDK	Rapid prototyping, enterprise apps
Unreal	OpenXR + platform plugins	High-fidelity experiences
Godot	Growing XR support	Open-source projects

B. Abstraction Layers

// Unity Input Abstraction Example
public interface IXRInput 
{
    Vector3 GetHandPosition(HandType hand);
    float GetGripValue(HandType hand);
}

// Platform-specific implementations
public class OculusInput : IXRInput { ... }
public class OpenXRInput : IXRInput { ... }

2. Key Development Approaches

A. API Standardization

• OpenXR (Khronos Group standard)
• Supported by Meta, Microsoft, Valve, etc.
• 60% reduction in platform-specific code

B. Asset Pipeline

graph TD
    A[3D Models] --> B{Platform Check}
    B -->|Quest| C[Android Texture Compression]
    B -->|PCVR| D[BC7 Compression]
    B -->|Vision Pro| E[USDZ Conversion]

3. Platform-Specific Considerations

A. Performance Profiles

Platform	CPU Budget	GPU Budget	Memory
Meta Quest 3	2ms/frame	5ms/frame	4GB
Pico 4	2.2ms/frame	5.5ms/frame	6GB
Apple Vision Pro	3ms/frame	8ms/frame	16GB

B. Input Systems

// Cross-platform input handling
InputDevices.GetDevicesWithCharacteristics(
    InputDeviceCharacteristics.Controller, 
    devices);

foreach (var device in devices)
{
    device.TryGetFeatureValue(CommonUsages.trigger, out float trigger);
    // Unified input processing
}

4. Build Automation

A. CI/CD Pipeline

# Sample GitHub Actions workflow
name: XR Multiplatform Build

jobs:
  build:
    strategy:
      matrix:
        platform: [quest, pico, steamvr]
    steps:
      - uses: actions/checkout@v3
      - run: unity-builder -platform ${{ matrix.platform }}

B. Conditional Compilation

#if OCULUS
    OculusIntegration.Initialize();
#elif OPENXR
    OpenXRLoader.Initialize();
#endif

5. Testing Matrix

Test Category	Meta Quest	Pico	SteamVR	Vision Pro
Controller Input	✓	✓	✓	Hand Tracking
Performance	72/90Hz	90Hz	120Hz	90Hz
Passthrough	B/W	B/W	N/A	Color

6. Emerging Standards

• OpenXR 1.1 (2024) – Enhanced hand tracking
• WebXR 2.0 – Browser-based AR improvements
• XRKit (Apple) – VisionOS ecosystem tools

Best Practice Checklist:
✔ Use OpenXR as base layer
✔ Abstract platform-specific features
✔ Implement automated platform testing
✔ Build asset variants during CI
✔ Profile on weakest platform first