1707798 - Flickering outline around objects on https://codepen.io/thebabydino/pen/WNGPjLx

Status: VERIFIED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Mayank Bansal]

Happens with both sw-wr and hw-wr
Go to https://codepen.io/thebabydino/pen/WNGPjLx

There is a flickering rectangle outline around the five-pointed and six-pointed stars on a string
There is a pentagonal radiating outline emerging from the 5-pointed 3d star

The page renders fine as of 24th Feb. I tried to do a regression, but the page crashed in some of the nightlies, and had other artifacts as well.
Not really sure if this is a sw-wr or hw-wr regression.

Comment 1

[Mayank Bansal]

Attachment: bandicam 2021-04-27 08-21-21-612.mp4

video of the issue

Comment 2

[Mayank Bansal]

I am blocking bug 1621381 for now as sw-wr is also affected by this bug.

Comment 3

[Lee Salzman [:lsalzman]]

(In reply to Mayank Bansal from comment #2)

I am blocking bug 1621381 for now as sw-wr is also affected by this bug.

Does this affect HW-WR? If so, then it shouldn't block sw-wr-correctness. Better wr-correctness.

Comment 4

[Mayank Bansal]

This looks to be regressed by bug 1706846
However, I use the term 'regress' a little losely. Bug 1706846 fixed a very apparent bug, and left this smaller regression.

Comment 5

[Alice0775 White]

I can reproduce the issue on Nightly90.0a1 Windows10. about:support shows that Compositing: WebRender.

There are several regression and progression.

#1 Regression window: Nothing is displayed, Nightly(content and UI) is completely blank. Occasionally the UI will blink.
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=7534ee1e10788b233ed6b27c6e120533870e5f2e&tochange=f3b8d237e29af262b2042809e13ce6043b75c922

#2 Regression window: Fixed #1 issue. However, The shape is not correct. It looks like a disk or with concentric circles.
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=24f7185528384b633771c837b1cf9a391eaa52f2&tochange=8f77fe5d56b270ccadf6c361e40412a12e56d4b9

#3 Regression window: Fixed #2 issue. However, This bug. Some outlines appear.
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=5c49b44eba9b8643e0c53254897b8382266c8ed8&tochange=9057a10b4b9c13275cb7314b90a42eb6e763da26

Comment 6

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1706846

Comment 7

[Lee Salzman [:lsalzman]]

Attachment: Bug 1707798 - Use rough clipping in cs_clip_image. r?aosmond

We were already clipping off most of the AA inside cs_clip_image previously anyway.
Given that it is too unpredictable in what situations the little bit of remaining
AA was actually applying, and that it causes visual artifacts sometimes when it
activates where it shouldn't, we're better off just using a rough clip inside this
shader for the most so that it is always predictable.

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/02dbc4ee200d
Use rough clipping in cs_clip_image. r=aosmond

Comment 9

[Lee Salzman [:lsalzman]]

Mayank, this patch should address the flickering outlines specifically. Can you check?

Comment 10

[Mayank Bansal]

sure. As soon as it hits nightly, can test.
Alternately, if you can point me to a Winx64 try build, I can test.

Comment 11

[Lee Salzman [:lsalzman]]

https://treeherder.mozilla.org/jobs?repo=try&revision=d43bc9faf210fdcba12135d445a2ad07e4e69245

Comment 12

[Mayank Bansal]

(In reply to Lee Salzman [:lsalzman] from comment #11)

https://treeherder.mozilla.org/jobs?repo=try&revision=d43bc9faf210fdcba12135d445a2ad07e4e69245

I dont know where to get the win10x64 build from this link. Is there an direct link?

Comment 13

[Lee Salzman [:lsalzman]]

https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/WcKiPz3nSDCPoPKsgDrhsA/runs/0/artifacts/public/build/target.zip

Comment 14

[Mayank Bansal]

(In reply to Lee Salzman [:lsalzman] from comment #13)

https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/WcKiPz3nSDCPoPKsgDrhsA/runs/0/artifacts/public/build/target.zip

The bug does not repro with this build :)

Edit: I also checked a couple of other demos, and they all looked fine.
Edit2 (to be doubly sure) : buildconfig from the try build : https://hg.mozilla.org/try/rev/d43bc9faf210fdcba12135d445a2ad07e4e69245

Comment 15

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/02dbc4ee200d

Comment 16

[Lee Salzman [:lsalzman]]

Comment on attachment 9218712 [details]
Bug 1707798 - Use rough clipping in cs_clip_image. r?aosmond

Beta/Release Uplift Approval Request

• User impact if declined: Potential anti-aliasing artifacts with some CSS transforms.
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): Slight cosmetic change to disable an old broken "feature". Verified fix.
• String changes made/needed:

Comment 17

[Pascal Chevrel:pascalc]

Comment on attachment 9218712 [details]
Bug 1707798 - Use rough clipping in cs_clip_image. r?aosmond

Approved alongside bug 1706846 and bug 1707228 for beta 9, thanks.

Comment 18

[Pascal Chevrel:pascalc]

https://hg.mozilla.org/releases/mozilla-beta/rev/f63d8899b0c8