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Version: 10 Jul 2024

Limitations and Workarounds

This document includes information on some of Unreal Engine's limitations and workarounds when building applications for Magic Leap 2.

Mixed Reality Streaming and Capture

If your project uses any mixed reality streaming or capture features, turn off the Mobile HDR rendering setting when packaging your app. This disables post-processing and ensures proper mixed reality capture on a real-world background instead of a virtual reality capture with a black background.

This issue occurs because Unreal Engine does not propagate the alpha channel from the base pass through the post-processing pipeline. Instead, the tonemapper sets a default alpha of 1.0 for every pixel. Since Unreal Engine uses inverted alpha in OpenXR, this results in all pixels being fully opaque.

How to Disable Mobile HDR

To disable the Mobile HDR setting when packaging your app:

  1. Open the Unreal Editor.
  2. From the main menu, select Edit > Project Settings.
  3. In the Project Settings window, navigate to Engine.
  4. Select Rendering.
  5. Under the VR section, deselect Mobile HDR.

Segmented Dimming

Segmented Dimming is currently not supported in Unreal Engine applications for Magic Leap 2. Even with Mobile HDR turned off, the alpha channel remains inverted, causing the background to be fully dimmed and content to appear translucent.

There are no effective workarounds for this issue. Developers can consider using remote rendering with post-processing to invert the alpha channel, though it may not be suitable due to performance impacts and complexity.