Bug 49021 – [chromium] Mac: WebGL: all textured content is blue

• Component: WebGL
• Status: RESOLVED FIXED

[Kenneth Russell]

https://bugs.webkit.org/show_bug.cgi?id=47974 introduced a regression in WebGL content in Chromium on Mac OS X where all textures have a blue tinge. I've definitively isolated the regression to that commit. Am currently investigating the root cause to propose a fix.

Layout test fast/canvas/webgl/tex-image-and-sub-image-2d-with-image.html, among others, should have caught this; we'll have to investigate separately why this wasn't caught until now.

[Zhenyao Mo]

fast/canvas/webgl/tex-image-and-sub-image-2d-with-image.html is skipped currently.  I just looked: a bunch of tests were skipped due to a image "shadow" issue, including several webgl tests.  I would think a patch caused so many test failures should be reverted instead of just masking out failing tests...

[Adam Barth]

There certainly were folks who wanted to revert the patch, and that would have been a more cautious path forward.

Please let me know how I can be helpful in fixing this issue.

[Kenneth Russell]

I don't want to impede forward progress by reverting the patch. Because it passes the vast majority of the layout tests it clearly doesn't have impact beyond WebGL.

I've identified the essential difference in behavior between the earlier and current image decoding paths and am working on a fix to the WebGL texture uploading code.

[Kenneth Russell]

(In reply to comment #1)
> fast/canvas/webgl/tex-image-and-sub-image-2d-with-image.html is skipped currently.  I just looked: a bunch of tests were skipped due to a image "shadow" issue, including several webgl tests.  I would think a patch caused so many test failures should be reverted instead of just masking out failing tests...

Ah. Yes, this is disheartening. The WebGL failure was incorrectly lumped in to the other failures.

[Kenneth Russell]

Created attachment 73012 [details]
Patch

[Zhenyao Mo]

Maybe now the indexed PNG files are supported?

[Adam Barth]

Comment on attachment 73012 [details]
Patch

Thanks for cleaning up my mess.  Sorry we screwed up recognizing the failure.

[Kenneth Russell]

Committed r71370: <http://trac.webkit.org/changeset/71370>

[Kenneth Russell]

(In reply to comment #6)
> Maybe now the indexed PNG files are supported?

Possibly but I doubt it since I didn't test it. My experience has been that if it isn't tested, it doesn't work.

[Zhenyao Mo]

Tested, with this decoder switch, indexed PNG files work fine in Chrome now, but not in Safari.  I really like it when a patch unintentionally fix some bugs.  :)