What causes split-screen cameras both drawing full screen?

Each camera defaults to a full 0,0,1,1 viewport rect, so both players' cameras render over the entire screen and the later one simply overwrites the first.

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 Split-Screen Cameras Both Drawing Full Screen in Unity

Quick answer: Set each camera's Viewport Rect to its half of the screen (for example 0,0,1,0.5 and 0,0.5,1,0.5) and give them distinct depth values so they composite correctly.

If both players see the full screen instead of a split, the cameras share the default viewport rect. Assigning halves fixes it. Here is how.

How to set it up

1. Set normalized viewport rects

Set player one's camera rect to new Rect(0,0.5f,1,0.5f) (top) and player two's to new Rect(0,0,1,0.5f) (bottom), or left/right halves with the x axis.

2. Order them with depth

Give the cameras different Depth values and set clear flags appropriately so they do not fight over which fills the shared screen first.

3. Fix per-viewport aspect

Each half has a different aspect ratio than the full screen, so set each camera's FOV or orthographic size for its viewport to avoid stretching.

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.

Reproduce it once with full context and the fix writes itself. The hunt is the expensive part.