Closed Bug 1723427 Opened 3 years ago Closed 2 years ago

CSS property backface-visibilty doesn’t properly deal with CSS property perspective


(Core :: Graphics: WebRender, defect)

Firefox 91



Tracking Status
firefox-esr78 --- wontfix
firefox-esr91 --- wontfix
firefox90 --- wontfix
firefox91 --- wontfix
firefox92 --- wontfix


(Reporter: mail, Unassigned)


(Blocks 2 open bugs, Regression)


(Keywords: regression)


(3 files, 1 obsolete file)

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0

Steps to reproduce:

I wrote a document that displays a cube using CSS, which rotates when hovered over, and which uses backface-visibility to hide faces that shouldn’t be visible, and perspective to create a 3D effect.

→ cube.html

Actual results:

The back faces of individual elements was still visible, they merely disappeared once the element would’ve had its back facing the camera had the perspective modifier not been there.

→ firefox-backface-visibility.mkv

Expected results:

The back faces should not appear (or the elements should disappear once their backs face the camera)

→ chromium-backface-visibility.mkv

Attached file cube.html (obsolete) —

The HTML file I used

A video recording of the problem in Firefox

A recording of the expected behavior in Chromium

The Bugbug bot thinks this bug should belong to the 'Core::WebRTC: Audio/Video' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

Component: Untriaged → WebRTC: Audio/Video
Product: Firefox → Core
Attached file cube.html

The actual HTML I used

Attachment #9234195 - Attachment is obsolete: true
Component: WebRTC: Audio/Video → Graphics
OS: Unspecified → Linux
Hardware: Unspecified → x86_64

I can reproduce the issue on Windows10.
If disabled WebRender then the problem is gone.

Ever confirmed: true
Keywords: regression
OS: Linux → All
Has Regression Range: --- → yes

:kvark, can you comment to the bug?

Flags: needinfo?(dmalyshau)
Assignee: nobody → dmalyshau
Severity: -- → S3
Flags: needinfo?(dmalyshau)

I can confirm the issue it started with version 91.x
Up to Version 90 the 3D Transformation with Firefox was correct!

I made a image to show the difference

Example Website:

Summary: backface-visibilty doesn’t properly deal with perspective → CSS property backface-visibilty doesn’t properly deal with CSS property perspective
See Also: → 1710764

This bug also occurs on Firefox Nightly on Android (93.0a1 (Build #2015828041))

This bug has been fixed for me on NixOS 22.05.20220321.1ec61dd (Quokka).

The bug assignee is inactive on Bugzilla, so the assignee is being reset.

Assignee: dmalyshau → nobody

This appears to be fixed by
2022-08-10T10:01:57.932000: DEBUG : Found commit message:
Bug 1695318 - Check if the parent node is perspective when considering back faces r=gw

Differential Revision:

2022-08-10T10:01:57.932000: DEBUG : Did not find a branch, checking all integration branches
2022-08-10T10:01:57.934000: INFO : The bisection is done.
2022-08-10T10:01:57.934000: INFO : Stopped

Closed: 2 years ago
Depends on: 1695318
Resolution: --- → FIXED
See Also: → 1783993

The original issue reported was fixed. However, a new regression has appeared that will be tracked by bug 1783993

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