How to Fix WebGL Gradient Banding in a GLSL Shader With Dithering

A mathematically smooth gradient still lands on only 256 levels per channel when written to a standard framebuffer, producing visible steps. Dithering trades imperceptible noise for perceived smoothness. Here is how to fix it.

How to fix it

1. Add ordered dithering

Sample a 4x4 Bayer matrix by screen position and add the small offset (scaled to 1/255) to the color before output so adjacent pixels round to different levels.

2. Use screen-space coordinates

Index the dither pattern by gl_FragCoord.xy so the noise is stable in screen space and does not crawl when the gradient surface moves.

3. Prefer blue noise for stillness

For static images a blue-noise texture lookup dithers with less visible structure than Bayer, at the cost of a small texture fetch per pixel.

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 HTML5 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.