1504817 - background png ends up interpolated when scrolled to 48000 pixels (background-repeat-large-area.html fuzzy reftest)

Status: NEW

(Core :: Graphics: WebRender, enhancement, P5)

Description

[Bobby Holley (:bholley)]

The background-repeat-large-area.html reftest is currently marked fuzzy. I happened to take a look at it, and the difference is as shown:

https://hg.mozilla.org/mozilla-central/raw-file/tip/layout/tools/reftest/reftest-analyzer.xhtml#logurl=https://queue.taskcluster.net/v1/task/QjL_als8TMeh7FGTM0_gig/runs/0/artifacts/public/logs/live_backing.log&only_show_unexpected=1

This suggests that we run into precision issues sampling a texture when the scroll offset is in the tens of thousands of pixels, which is potentially something the user might run into.

This probably doesn't block, but getting it on file as a p4.

Comment 1

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Pernosco session: https://pernos.co/debug/wHNwLP576dCy7C5zgEcYgw/index.html