Bug 181007

Summary:

WebGL canvas with enabled blending and no antialiasing is incorrectly composed with background

Product:

WebKit

Reporter:

Kirill S. Dmitrenko <kdmitrenko>

Component:

WebGL

Assignee:

Nobody <webkit-unassigned>

Status:

RESOLVED CONFIGURATION CHANGED

Severity:

Normal

CC:

dino, gman, jonlee, kkinnunen, simon.fraser, webkit-bug-importer

Priority:

Keywords:

InRadar

Version:

Safari 11

Hardware:

Mac

OS:

macOS 10.12

Attachments:

Description	Flags
Expected result	none
Actual result in Safari 11.0.3	none
Code of the test page	none

Kirill S. Dmitrenko

Reported 2017-12-19 16:00:11 PST

Created attachment 329849 [details] Expected result If threre's a html element with a background underneath the canvas, and blending is enabled in the context, composition for some reason goes "additive". Here's a test page: https://codepen.io/dmikis/full/ZvQPBG/.

Attachments
Expected result (325.37 KB, image/png) 2017-12-19 16:00 PST, Kirill S. Dmitrenko	no flags	Details
Actual result in Safari 11.0.3 (203.04 KB, image/png) 2017-12-19 16:00 PST, Kirill S. Dmitrenko	no flags	Details
Code of the test page (3.36 KB, application/zip) 2017-12-19 16:01 PST, Kirill S. Dmitrenko	no flags	Details
View All Add attachment proposed patch, testcase, etc.

Kirill S. Dmitrenko

Comment 1 2017-12-19 16:00:41 PST

Created attachment 329850 [details] Actual result in Safari 11.0.3

Kirill S. Dmitrenko

Comment 2 2017-12-19 16:01:07 PST

Created attachment 329851 [details] Code of the test page

Radar WebKit Bug Importer

Comment 3 2017-12-19 17:21:19 PST

<rdar://problem/36145405>

Kirill S. Dmitrenko

Comment 4 2018-01-09 06:28:45 PST

I forgot to mention that the problem reproduces only on discrete GPUs.

Dean Jackson

Comment 5 2018-01-12 15:23:16 PST

We can reproduce. We've forwarded on to our compositing team.

Kirill S. Dmitrenko

Comment 6 2018-01-31 05:18:39 PST

We've got more complaint from users, and it seems that on some configuration antialiasing doesn't affect the problem (i.e., if antialias is set, rendered result is still "blended" with CSS background). In particular, on macOS 10.11 and 10.13 the problem occurs.

Simon Fraser (smfr)

Comment 7 2018-11-28 13:38:59 PST

The test page no longer works (stv.maps.yandex.net now gives 404 errors).

Simon Fraser (smfr)

Comment 8 2018-11-28 13:49:17 PST

Also, this should have been fixed in macOS Mojave. Can you test and report back?

Gregg Tavares

Comment 9 2019-06-10 23:11:34 PDT

this seems fixed to me. Tested on MacOS 10.14.5 on 2014 MBP and on iOS 12.3.1 iPhoneX Mark as resolved?

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