NEW 214660
markContextChangedAndNotifyCanvasObserver and markContextChanged over-notify 
https://bugs.webkit.org/show_bug.cgi?id=214660
Summary markContextChangedAndNotifyCanvasObserver and markContextChanged over-notify
Kenneth Russell
Reported 2020-07-22 15:07:52 PDT
WebGLRenderingContextBase::markContextChanged and WebGLRenderingContextBase::markContextChangedAndNotifyCanvasObserver dispatch too many notifications: - markContextChangedAndNotifyCanvasObserver doesn't take into account whether a user-level framebuffer is bound. If one is, then it shouldn't notify. - markContextChanged calls "htmlCanvas()->clearCopiedImage()" and "renderBox->contentChanged(CanvasPixelsChanged)" for every draw call - this seems expensive. dino@ indicated in discussion on Slack that with the addition of WebGLRenderingContextBase::prepareForDisplay in Bug 212461, at least some of these notifications can be done once per frame, at the end of the frame, rather than on each operation that might touch the WebGL back buffer.
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Kenneth Russell
Comment 1 2020-07-22 15:08:57 PDT
Noticed this while fixing Bug 126447 and Bug 126448.
Radar WebKit Bug Importer
Comment 2 2020-07-29 15:08:37 PDT
<rdar://problem/66294753>
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