What causes z-fighting between flat particles and a surface?

A flat particle sits exactly on a surface at the same depth, so depth precision causes the two to flicker as the renderer cannot decide which is in front.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix Z-Fighting Between Flat Particles and Surfaces

Quick answer: Lift the particle slightly off the surface, apply a depth bias/offset, or render it with depth test but no depth write in the transparent queue.

Coplanar transparent particles fight with the surface they sit on because their depths are nearly equal. A small offset or depth-write change resolves the flicker. Here is how.

How to fix it

1. Add a small position offset

Raise the particle a tiny amount along the surface normal (a few millimeters) so it is unambiguously in front of the floor and no longer shares the same depth.

2. Apply a depth bias

Use a shader Offset/polygon-offset (or the material's depth bias) to push the particle's depth slightly toward the camera without visibly moving it, eliminating the fight.

3. Render transparent without depth write

Put the effect in the transparent queue with depth write off so it depth-tests against opaque geometry but does not contend with itself or other coplanar transparents.

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 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.

Most of the time the fix is small. Seeing the failure clearly is the part that actually costs you.