[Webkit-unassigned] [Bug 226254] New: Premultiplication handled incorrectly for WebGL canvases display and upload

bugzilla-daemon at webkit.org bugzilla-daemon at webkit.org
Tue May 25 17:54:55 PDT 2021


https://bugs.webkit.org/show_bug.cgi?id=226254

            Bug ID: 226254
           Summary: Premultiplication handled incorrectly for WebGL
                    canvases display and upload
           Product: WebKit
           Version: Safari Technology Preview
          Hardware: Mac (Intel)
               URL: https://codepen.io/kainino0x/pen/oNZwoJQ
                OS: macOS 11
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: WebGL
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: kainino at google.com
                CC: dino at apple.com, kbr at google.com, kkinnunen at apple.com

Created attachment 429720

  --> https://bugs.webkit.org/attachment.cgi?id=429720&action=review

Reproduction case

1. Open https://codepen.io/kainino0x/pen/oNZwoJQ (or the attached file)

Expected result:
The six WebGL-rendered canvases should match the six 2d-rendered canvases (with the exception described in the test case).

Actual result:
See attached. From inspection, I think (but I'm not sure):
- Canvases with premultiplyAlpha:false are treated as if they have premultiplyAlpha:true
  (both when they are displayed, and when they are used as sources to texImage2D).
- texImage2D from webgl canvas sources with premultiplyAlpha:false are incorrectly y-flipped.

On macOS 11.3.1 (20E241):

- Pass: Chrome - 92.0.4515.7 (Official Build) canary (x86_64)
- Pass: Firefox - 90.0a1 (2021-05-18) (64-bit)
- FAIL: Safari Stable - Version 14.1 (16611.1.21.161.6)
- FAIL: Safari Technology Preview - Release 124 (Safari 14.2, WebKit 16612.1.11.10)

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.webkit.org/pipermail/webkit-unassigned/attachments/20210526/08e27c14/attachment-0001.htm>


More information about the webkit-unassigned mailing list