Bug 137752

Summary: glReadPixels on NVidia cards return the wrong values for the alpha channel when alpha is off
Product: WebKit Reporter: Roger Fong <roger_fong>
Component: WebGLAssignee: Nobody <webkit-unassigned>
Status: RESOLVED DUPLICATE    
Severity: Normal CC: bfulgham, commit-queue, dino, jonlee, kondapallykalyan, noam, roger_fong
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: PC   
OS: Unspecified   
Bug Depends on: 137790    
Bug Blocks:    
Attachments:
Description Flags
patch bfulgham: review+

Roger Fong
Reported 2014-10-15 13:18:16 PDT
When you create a rendering context with alpha:false, this means that the context returned should be opaque. However, with nvidia cards, calling glreadpixels on such contexts returns the wrong value. It returns 0's in the alpha channel, they should be 255 instead. As a workaround for this, after calls to ::glReadPixels we should manually set the alpha channel to 255 if alpha is off for the context.
Attachments
patch (3.28 KB, patch)
2014-10-15 13:42 PDT, Roger Fong 		bfulgham: review+
DetailsFormatted DiffDiff
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Roger Fong
Comment 1 2014-10-15 13:20:46 PDT
<rdar://problem/15408133> I believe this is the last failing 1.0.2 test on at least the 2 nvidia cards i've tested on. (the 9600M GT and the 750 M)
Roger Fong
Comment 2 2014-10-15 13:42:50 PDT
Created attachment 239892 [details] patch
Brent Fulgham
Comment 3 2014-10-15 13:53:30 PDT
Comment on attachment 239892 [details] patch View in context: https://bugs.webkit.org/attachment.cgi?id=239892&action=review Looks good. Could you please mention the two failing tests that you have fixed with this change? Thanks. > ChangeLog:7 > + Reviewed by NOBODY (OOPS!). Can you list the two failing tests that were fixed by this?
Roger Fong
Comment 4 2014-10-15 14:41:38 PDT
Committed with mention of fixed test in changelog. http://trac.webkit.org/changeset/174744
WebKit Commit Bot
Comment 5 2014-10-16 14:50:02 PDT
Re-opened since this is blocked by bug 137790
Roger Fong
Comment 6 2014-10-16 23:44:41 PDT
Closing this since I filed another bug for the issue. *** This bug has been marked as a duplicate of bug 137793 ***
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