88265 2012-06-04 16:25:16 -0700 [Chromium] Avoid issuing glClear for opaque render surfaces. 2013-04-15 07:32:54 -0700 1 1 1 Unclassified WebKit WebCore Misc. 528+ (Nightly build) Unspecified Unspecified RESOLVED WONTFIX P2 Normal --- 1 reveman webkit-unassigned danakj enne jamesr schenney oldest_to_newest 640967 0 reveman 2012-06-04 16:25:16 -0700 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. 641586 1 danakj 2012-06-05 08:28:10 -0700 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? 641617 2 reveman 2012-06-05 09:04:09 -0700 (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? 641656 3 danakj 2012-06-05 09:47:21 -0700 Yeh I toyed with that idea as well. We can, when the owning layer drawsContents and its content size == the surface size. 875800 4 schenney 2013-04-15 07:32:54 -0700 https://code.google.com/p/chromium/issues/detail?id=231338