What causes peter-panning where shadows detach from their objects?

A shadow depth bias set too high pushes the shadow sample away from the geometry, so contact shadows lift off and the object appears to hover.

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 Peter-Panning Where Shadows Detach From Objects

Quick answer: Lower the constant depth bias and rely on a small slope-scaled normal bias instead, and raise shadow map resolution so less bias is needed.

Peter-panning is the gap between an object's feet and its shadow. It comes from too much shadow bias compensating for acne. Dial the bias back and the contact shadow returns.

How to fix it

1. Reduce the depth bias

A large constant depth bias is the usual culprit. Lower it until contact shadows touch the geometry again, then stop just before acne reappears.

2. Prefer normal bias

Switch most of the offset to a slope-scaled normal bias, which pushes the sample along the surface normal only where needed, instead of a flat depth push that lifts every shadow.

3. Raise shadow resolution

Higher shadow map resolution and tighter cascade ranges shrink the bias you need, because each texel covers less world space and self-shadowing artifacts get smaller.

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.

The bug you can't reproduce isn't gone — it's just invisible until you capture it from the player's device.