How to Fix a VR Effect Rendering in Only One Eye with Instanced Stereo in Unreal

Instanced stereo rendering draws both eyes efficiently in Unreal, but custom materials that read screen-space or view vectors must use the resolved per-eye view. Code written against a single view renders correctly in one eye and breaks or vanishes in the other.

How to fix it

1. Use the resolved view

In custom HLSL material nodes, reference ResolvedView rather than View so per-eye matrices and buffers are correct under instanced stereo.

2. Avoid single-view screen reads

Replace raw screen-position math with stereo-aware nodes so scene-color and depth samples target the right eye.

3. Match project settings

Confirm Instanced Stereo (or Mobile Multi-View on standalone) is set consistently and that the effect's render pass supports it.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every Unreal Engine error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.