1696439 - Radial gradient demo renders incorrectly with sw-wr

Status: VERIFIED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Mayank Bansal]

1. Enable sw-wr
2. Go to https://cssgradient.io/
3. Scroll around the middle, till you see "radial gradient css" in the right
   OR search for "radial gradient css"
4. Hover mouse over the demo

AR: renders incorrectly
ER: not so

Comment 1

[Mayank Bansal]

Attachment: bug.png

sw-wr on left. Hw-WR on right

Comment 2

[Mayank Bansal]

Attachment: about:support with forced sw-wr

Comment 3

[Mayank Bansal]

2021-03-04T22:32:47.533000: DEBUG : Found commit message:
Bug 1682194 - Accelerate cs_clip_rectangle in SWGL. r=jrmuizel

cs_clip_rectangle is slow because we evaluate distance AA for every fragment
the shader touches. With SWGL, we can do much better since we have control
over span. We calculate an inner opaque octagon which can just use a cheap
solid fill and an outer AA octagon within which we need to actually we do
AA and outside which we can just do another solid clear. This reduces most
of the cost of rounded-rectangles to just some setup work, a few fragments
of distance AA on the ends of a span, and large runs of solid color where
we don't have to do much work.

Differential Revision: https://phabricator.services.mozilla.com/D106658

2021-03-04T22:32:47.533000: DEBUG : Did not find a branch, checking all integration branches
2021-03-04T22:32:47.533000: INFO : The bisection is done.
2021-03-04T22:32:47.533000: INFO : Stopped

Comment 4

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

Set release status flags based on info from the regressing bug 1682194

Comment 5

[Julien Cristau [:jcristau]]

sw-wr is off in late beta

Comment 6

[Lee Salzman [:lsalzman]]

Attachment: Reduced testcase

This is a reduced testcase that seems to reproduce the issue. There seems to be an interaction here between border-radius and transforms that is necessary to cause the issue.

Comment 7

[Lee Salzman [:lsalzman]]

Attachment: Bug 1696439 - Fix corner apex distance calculation in cs_clip_rectangle. r?jrmuizel

This fixes a bug wherein we were calculating the distance to the corner apex incorrectly
which could result in it being clipped in the presence of transforms that cause the step
scale to not be axis-aligned.

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/fade9b09b56a
Fix corner apex distance calculation in cs_clip_rectangle. r=jrmuizel

Comment 9

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/fade9b09b56a

Comment 10

[Mayank Bansal]

this is fixed in the latest nightly

Comment 11

[Alexandru Trif, Desktop QA [:atrif]]

Reproduced the issue using Firefox 89.0a1 (20210304215542) and sw-wr with the attached test case and the provided link.
The issue is verified fixes with Firefox 88.0b7 (20210404185932) on Windows 10x64, macOS 10.12 and Ubuntu 20.04. The test case and the website from comment 0 are properly displayed with gfx.webrender.software:true