How to Fix a URP Distortion Shader Sampling an Empty Opaque Texture in Unity

Screen-space distortion grabs the already-rendered scene from the opaque color texture and offsets its UVs. If that texture is off, or you sample it before opaques finish, you get black. Here is how to fix it.

How to fix it

1. Enable the Opaque Texture

In the URP Renderer/Pipeline asset tick Opaque Texture so URP captures _CameraOpaqueTexture after opaque rendering for transparent passes to sample.

2. Render in the Transparent queue

Set the distortion shader to Queue=Transparent; opaque-queue objects render before the opaque texture exists and will sample nothing.

3. Sample with screen-space UVs

Compute UVs from the clip-space position (i.screenPos.xy / i.screenPos.w) plus your distortion offset, then SAMPLE_TEXTURE2D(_CameraOpaqueTexture, ...) to read the scene behind.

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 Unity 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.