Bug 94961 – WebGL should not flip textures on presentation if contents are unchanged

• Status: RESOLVED
• Resolution: FIXED
• Component: New Bugs

[James Robinson]

WebGL should not flip textures on presentation if contents are unchanged

[James Robinson]

Created attachment 160461 [details]
Patch

[James Robinson]

The bug is chromium-specific (afaik) but the fix touches cross-platform code, so I haven't marked this with [chromium]. I think this could also be solved in a chromium-specific way that doesn't touch DrawingBuffer at all but this seems to me like something DrawingBuffer should be able to handle.

[Kenneth Russell]

Comment on attachment 160461 [details]
Patch

The fix looks good as far as I can see. Some additional test cases to try would include printing of WebGL content, the other WebGL layout tests, and various demos on the web. r=me

[James Robinson]

(In reply to comment #3)
> (From update of attachment 160461 [details])
> The fix looks good as far as I can see. Some additional test cases to try would include printing of WebGL content, the other WebGL layout tests, and various demos on the web. r=me

Thanks for the review.  I'll check these locally before landing - our automated testing of things like webgl printing hasn't been too reliable in the past.  Is there a way to force AA off for local testing other than code modification, by any chance?

[Kenneth Russell]

(In reply to comment #4)
> (In reply to comment #3)
> > (From update of attachment 160461 [details] [details])
> > The fix looks good as far as I can see. Some additional test cases to try would include printing of WebGL content, the other WebGL layout tests, and various demos on the web. r=me
> 
> Thanks for the review.  I'll check these locally before landing - our automated testing of things like webgl printing hasn't been too reliable in the past.  Is there a way to force AA off for local testing other than code modification, by any chance?

zmo added the command line option --disable-gl-multisampling a while back; I think it should still work.

[James Robinson]

Printing appears to be broken with or without this patch - after printing the WebGL content is cleared.  I don't know how long this has been broken.  Most pages / demos repaint the canvas on every frame so this problem is transient.  Filed https://bugs.webkit.org/show_bug.cgi?id=95140 to cover that bug.  I don't think this patch makes anything worse.

[Kenneth Russell]

(In reply to comment #6)
> Printing appears to be broken with or without this patch - after printing the WebGL content is cleared.  I don't know how long this has been broken.  Most pages / demos repaint the canvas on every frame so this problem is transient.  Filed https://bugs.webkit.org/show_bug.cgi?id=95140 to cover that bug.  I don't think this patch makes anything worse.

Darn it. Thanks for testing anyway. Please go ahead with your patch.

[James Robinson]

Committed r126810: <http://trac.webkit.org/changeset/126810>