1757201 - invalidation bug with text-shadows + mix-blend-mode

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Aria Beingessner [:Gankra]]

Attachment: about:support

STR:

• go to https://gankra.github.io/blah/
• resize the window horizontally

alternative:

• go to https://gankra.github.io/blah/
• scroll down to the bottom of the page
• scroll back to the top of the page

expected result:

chromatic abberation-y "Faultlore" text should render properly (colored fringing but coherent)

actual result:

chromatic abberation-y "Faultlore" text has huge random blocks of solid red, is clearly being invalidated wrong

---

I incidentally already have a mostly reduced example of this at https://gankra.github.io/blah/rustblog/before.html.

The problematic input is:

• 3 nested copies of the text "Faultlore"
• text set to transparent
• each textrun has a different color shadow at a different offset (cyan, magenta, yellow)
• the textruns are merged with mix-blend-mode: darken

The net effect of this is that you get colorful printer-style bleeding around the edges but where the shadows all overlap you get a fairly clean black copy of the text. This is obviously very evil and not terribly surprising that it breaks webrender.

This appears to be a recent regression. I developed and tested this abomination in firefox nightly on this machine only a few days ago, and resizing the window never corrupted the result during that time.

Comment 1

[Aria Beingessner [:Gankra]]

Attachment: good render (microsoft edge).png

Comment 2

[Aria Beingessner [:Gankra]]

Attachment: bad render (firefox nightly).png

Comment 3

[Aria Beingessner [:Gankra]]

not 100% sure this is invalidation after messing around with window resizing, but these corruption patterns are so weird that there's something clearly very messed up happening.

Comment 4

[Mayank Bansal]

if it glitches for you if you pinch-zoom, might be a dupe of bug 1756929

Comment 5

[Alice0775 White]

[Tracking Requested - why for this release]:

Regression window:

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=c6f1243c3ba45a4ad3cfd1cacdbf12ad377b4a81&tochange=fc2b3d6448bcc3575fffb1abc923e7e703aeef54

Comment 6

[Glenn Watson [:gw]]

Attachment: g1.html

A slightly more reduced test case

Comment 7

[Pascal Chevrel:pascalc]

Regressor landed in 99

Comment 8

[Glenn Watson [:gw]]

Setting gfx.webrender.debug.force-picture-invalidation works around it for me, looks to be an issue where we don't invalidate either the correct bounding rects, or deeply enough in the surface hierarchy.

Comment 9

[Glenn Watson [:gw]]

Hmm, looks like there are two issues - setting gfx.webrender.debug.force-picture-invalidation fixes one problem, but there's still glitches during resize which look like a different bug.

Comment 10

[Glenn Watson [:gw]]

Attachment: Bug 1757201 - Fix mix-blend mode on parent surfaces with snapping enabled

Comment 11

[Mayank Bansal]

possible to get a try build for testing?

Comment 12

[Glenn Watson [:gw]]

(In reply to Mayank Bansal from comment #11)

possible to get a try build for testing?

Yup, you beat me to it - was just about it post it (artifacts not available yet but should be soon).

https://treeherder.mozilla.org/jobs?repo=try&revision=422897f59ab4bb22f71da5d2c68426ebb86ab467

Comment 13

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7aaefe97188d
Fix mix-blend mode on parent surfaces with snapping enabled r=gfx-reviewers,lsalzman

Comment 14

[Pulsebot]

Backout by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d6aabaf771d4
Backed out changeset 7aaefe97188d for causing bustage in mix-blend-layers.yaml CLOSED TREE

Comment 15

[Noemi Erli[:noemi_erli]]

Backed out changeset 7aaefe97188d (Bug 1757201) for causing bustage in mix-blend-layers.yaml CLOSED TREE

Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&group_state=expanded&collapsedPushes=842382&resultStatus=testfailed%2Cbusted%2Cexception%2Cretry%2Cusercancel&revision=7aaefe97188d8b0f65da8e52980de830761a8153&selectedTaskRun=RyKWjRUUR76UF8ezdXT9ZA.0

Log: https://treeherder.mozilla.org/logviewer?job_id=369603264&repo=autoland&lineNumber=1830

Backout: https://hg.mozilla.org/integration/autoland/rev/d6aabaf771d4c6ee0a63b24e79b3afe379ce7bd6

Comment 16

[Glenn Watson [:gw]]

Added a bit of fuzziness to account for android hardware rendering and re-pushed.

Comment 17

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/157f7165d8d9
Fix mix-blend mode on parent surfaces with snapping enabled r=gfx-reviewers,lsalzman

Comment 18

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/157f7165d8d9

Comment 19

[Andra Esanu]

(In reply to Noemi Erli[:noemi_erli] from comment #18)

https://hg.mozilla.org/mozilla-central/rev/157f7165d8d9

== Change summary for alert #33487 (as of Mon, 07 Mar 2022 11:27:48 GMT) ==

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)
149%	motionmark_webgl 3DGraphics-WebGL	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	4.09 -> 10.18
143%	motionmark_webgl 3DGraphics-WebGL	linux1804-64-shippable-qr	e10s fission stylo webrender	4.26 -> 10.34
40%	motionmark_webgl 3DGraphics-WebGL	linux1804-64-shippable-qr	e10s fission stylo webrender	7.10 -> 9.93
21%	glvideo Mean tick time across 100 ticks:	linux1804-64-shippable-qr	e10s fission stylo webrender	21.84 -> 17.17
20%	glvideo Mean tick time across 100 ticks:	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	21.54 -> 17.14

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=33487

Comment 20

[Monica Chiorean]

I was able to reproduce the issue on Win10x64 using build 99.0a1(20220225104705), when scrolling up/down text appears Red.
Verified as fixed on Win10x64 / Ubuntu 20.4 / Mac 10.13 using builds: 99.0b4(20220315185755) and 100.0a1 (20220316095231).

Comment 21

[Dave Hunt [:davehunt] [he/him] ⌚BST]

(In reply to Andra Esanu from comment #19)

(In reply to Noemi Erli[:noemi_erli] from comment #18)

https://hg.mozilla.org/mozilla-central/rev/157f7165d8d9

== Change summary for alert #33487 (as of Mon, 07 Mar 2022 11:27:48 GMT) ==

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)
149%	motionmark_webgl 3DGraphics-WebGL	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	4.09 -> 10.18
143%	motionmark_webgl 3DGraphics-WebGL	linux1804-64-shippable-qr	e10s fission stylo webrender	4.26 -> 10.34
40%	motionmark_webgl 3DGraphics-WebGL	linux1804-64-shippable-qr	e10s fission stylo webrender	7.10 -> 9.93
21%	glvideo Mean tick time across 100 ticks:	linux1804-64-shippable-qr	e10s fission stylo webrender	21.84 -> 17.17
20%	glvideo Mean tick time across 100 ticks:	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	21.54 -> 17.14

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=33487

:jgilbert there are some significant improvements associated with this change, can you confirm these are expected/genuine?

Comment 22

[Kelsey Gilbert [:jgilbert]]

@gw these seem high, or is this a kind of small-change-big-effect we expect here?

Comment 23

[Glenn Watson [:gw]]

The patch in this bug should only affect mix-blend-mode elements (and I wouldn't expect a major performance difference), which I doubt the above tests have? So it seems likely to be unrelated to this bug, perhaps an incorrect attribution?

Comment 24

[Dave Hunt [:davehunt] [he/him] ⌚BST]

Andra, could you review the alert to see if this is the correct bug to associate with this improvement?

Comment 25

[Andra Esanu]

Thank you for this. It seems the culprit was a bit earlier, I've linked the alert to bug 1638466.