1486113 - A straight line on the side of a spinning cube became wavy (Mozilla Monument Name Finder)

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect, P2)

Description

[Darkspirit]

Attachment: 2018-08-24_23-03-15.mp4

Debian Testing, KDE, Xorg, Nvidia GTX 1060 (Driver 390.77)

mozregression --good 2018-07-01 --bad 2018-08-24 --pref gfx.webrender.all:true -a http://thewebrocks.com/demos/mozilla-monument-name-finder/
> 7:12.65 INFO: Last good revision: 32a8875a1721cd9369931bb5e1b74da448455bff
> 7:12.65 INFO: First bad revision: b6f3d38d8da5c786f3160c24960001d88ae86a28
> 7:12.65 INFO: Pushlog:
> https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=32a8875a1721cd9369931bb5e1b74da448455bff&tochange=b6f3d38d8da5c786f3160c24960001d88ae86a28

> b6f3d38d8da5	Kartikaya Gupta — Bug 1479432 - Update Cargo lockfiles and re-vendor rust dependencies. r=jrmuizel
> 4088993297c4	Kartikaya Gupta — Bug 1479432 - Update webrender to commit 7a1b919e37d6cd0155077aa90f98cfcdf9fa5bae. r=jrmuizel

> WR @ 2343e9b2f999c294b87ba64da8b05d30cc12db70
mozregression --repo try --launch c77fdf2c2cb28beb8823bbafd9aff07fd7ee13b1 --pref gfx.webrender.all:true -a http://thewebrocks.com/demos/mozilla-monument-name-finder/
last good

> WR @ c8f8491d16fd9b12d5eeff93ccfd33f01489087b
mozregression --repo try --launch cd5357171dd8108003f6a89486f9f6d1fc9f8e58 --pref gfx.webrender.all:true -a http://thewebrocks.com/demos/mozilla-monument-name-finder/
first bad

Regression range: https://github.com/servo/webrender/compare/2343e9b2f999c294b87ba64da8b05d30cc12db70...c8f8491d16fd9b12d5eeff93ccfd33f01489087b
= servo/webrender#2939

Comment 1

[Darkspirit]

(Screencast: Left window is non-WR.)

Comment 2

[Dzmitry Malyshau [:kvark]]

Thanks for diagnosing and finding the regression range!

Comment 3

[Dzmitry Malyshau [:kvark]]

This is actually a plane splitting issue, so I don't think the suspected PR #2939 is relevant here.
The front face gets split in 2 and the back face gets drawn in-between for some reason. This is a good case to investigate, although I don't think it's the highest priority right now.

Comment 4

[Markus Stange [:mstange]]

Why does the paint order affect the straightness of the line?

Comment 5

[Markus Stange [:mstange]]

Attachment: screenshot

Comment 6

[Dzmitry Malyshau [:kvark]]

Markus, I didn't realize that this line is supposed to be straight :) I was looking at a corruption that's visible on those numbers at certain angles. Lemme go back to that issue and look at the lines...

Comment 7

[Dzmitry Malyshau [:kvark]]

Fix for straight lines is coming in https://github.com/servo/webrender/pull/2991