RESOLVED WONTFIX88265
[Chromium] Avoid issuing glClear for opaque render surfaces. 
https://bugs.webkit.org/show_bug.cgi?id=88265
Summary [Chromium] Avoid issuing glClear for opaque render surfaces.
David Reveman
Reported 2012-06-04 16:25:16 PDT
We're currently issuing a glClear for all render surfaces except the root render surface. We should avoid issuing a glClear for opaque render surfaces.
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Dana Jansens
Comment 1 2012-06-05 08:28:10 PDT
Checking if a render surface is opaque is a bit annoying though. You'll need to merge all the opaque rects from its entire subtree. Will this work be < the work to clear?
David Reveman
Comment 2 2012-06-05 09:04:09 PDT
(In reply to comment #1) > Checking if a render surface is opaque is a bit annoying though. You'll need to merge all the opaque rects from its entire subtree. Will this work be < the work to clear? That's hard to say as the glClear is done by the GPU while figuring out if we have to do the clear is of course not. I doesn't have to be perfect. Could we just use the opaqueness of the owning layer as a start?
Dana Jansens
Comment 3 2012-06-05 09:47:21 PDT
Yeh I toyed with that idea as well. We can, when the owning layer drawsContents and its content size == the surface size.
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