Bug 88265 - [Chromium] Avoid issuing glClear for opaque render surfaces.
Summary: [Chromium] Avoid issuing glClear for opaque render surfaces.
Status: RESOLVED WONTFIX
Alias: None
Product: WebKit
Classification: Unclassified
Component: WebCore Misc. (show other bugs)
Version: 528+ (Nightly build)
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Nobody
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2012-06-04 16:25 PDT by David Reveman
Modified: 2013-04-15 07:32 PDT (History)
4 users (show)

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Description David Reveman 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.
Comment 1 Dana Jansens 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?
Comment 2 David Reveman 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?
Comment 3 Dana Jansens 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.