Advanced

• Version 1.0.2
• Device: Youbiquo Leonardo XR
• Base SDK: Snapdragon Spaces 1.0.4

This section covers advanced configurations and features available on LeonardoXR, divided into general Snapdragon Spaces platform functionality and LeonardoXR proprietary advanced features.

Advanced — Snapdragon Spaces

Adding a New Interaction Profile

To use an interaction profile not included in the Snapdragon Spaces plugin:

1. Go to Project Settings > XR Plug-in Management > OpenXR (Android) > Interaction Profiles.
2. Add the desired profile by clicking the + button.
3. Configure the corresponding Input Actions in the Input System Asset.

Custom Controller

Describes how to build a custom Android controller archive (.aar) using the Custom Controller Package — the Android Studio project included in the developer package.

Process Overview

1. Open the Android Studio project included in the Snapdragon Spaces developer package.
2. Modify the companion Activity as needed (layout, buttons, additional axes).
3. Build the project to obtain a .aar file.
4. Import the .aar into the Unity project as a native Android plugin (in Assets/Plugins/Android).
5. Configure the Android manifest to declare the new Activity.

NOTE Adding a custom controller archive can cause Gradle caching errors. If build errors occur, delete the Temp/gradleOut folder and rebuild.

Display Refresh Rate

The XR_EXT_display_refresh_rate extension allows querying and setting the display refresh rate at runtime.

Query Current Refresh Rate

using Qualcomm.Snapdragon.Spaces;

BaseRuntimeFeature baseRuntime = OpenXRSettings.Instance.GetFeature<BaseRuntimeFeature>();
float currentHz = baseRuntime.GetDisplayRefreshRate();
Debug.Log($"Current refresh rate: {currentHz} Hz");

Get Supported Refresh Rates

float[] supportedRates = baseRuntime.GetSupportedDisplayRefreshRates();
foreach (float rate in supportedRates)
    Debug.Log($"Supported: {rate} Hz");

Set Refresh Rate

baseRuntime.RequestDisplayRefreshRate(90.0f);

NOTE The requested refresh rate must be among those returned by GetSupportedDisplayRefreshRates(). Unsupported values are ignored.

Advanced Android Thread Performance

The SpacesThreadUtility component improves thread scheduling priority on Android, producing more consistent frame timing.

Setup

Add the SpacesThreadUtility component to a persistent GameObject in the scene (e.g. the same GameObject hosting the AR Session or XR Origin). No configuration is required — it activates automatically on initialisation and acts on the main Unity threads.

When to Use

Recommended for all LeonardoXR applications that exhibit framerate jitter or frame timing variability, especially in scenes with heavy rendering or many active AR subsystems.

Performance Settings

The OpenXR extension XR_EXT_performance_settings exposes performance level hints for CPU and GPU via a new method on BaseRuntimeFeature.

using Qualcomm.Snapdragon.Spaces;
using UnityEngine.XR.OpenXR;

BaseRuntimeFeature baseRuntime = OpenXRSettings.Instance.GetFeature<BaseRuntimeFeature>();
baseRuntime.SetPerformanceLevel(PerformanceDomain.Cpu, PerformanceLevel.SustainedHigh);
baseRuntime.SetPerformanceLevel(PerformanceDomain.Gpu, PerformanceLevel.SustainedHigh);

NOTE The Boost level consumes significantly more power and may cause thermal throttling if sustained. Use it only for brief critical operations (e.g. loading a heavy scene).

Advanced — LeonardoXR

QNN Inference Plugin — Advanced Guide

DOCUMENTATION IN PROGRESS This section will cover advanced usage of the QNN (Qualcomm Neural Network) Inference Plugin on Leonardo XR, including:

• Model preparation and conversion (ONNX → QNN format).
• Loading models at runtime via plugin APIs.
• Running inference on the NPU with input/output tensor management.
• Memory management and throughput optimisation.
• Debug and performance profiling of inference.
• Use cases: object detection, pose estimation, real-time segmentation.

Detailed documentation will be available in a future release.

Intercept OpenXR Function — Advanced Guide

DOCUMENTATION IN PROGRESS This section will cover advanced usage of the Intercept OpenXR Function mechanism on Leonardo XR, including:

• Architecture of the OpenXR interception layer.
• Registering custom handlers for specific OpenXR functions.
• Use cases: rendering pipeline override, custom data injection into the XR layer, low-level OpenXR debugging.
• Safety and stability considerations.
• Interaction with other LeonardoXR SDK components.

This feature is intended for developers with direct experience of low-level OpenXR APIs. Detailed documentation will be available in a future release.