[Webkit-unassigned] [Bug 249583] New: [GTK][WPE][Compositing] Dynamically drawn HTML elements are not correctly composed when css-transformed with the EGL renderer

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=249583

            Bug ID: 249583
           Summary: [GTK][WPE][Compositing] Dynamically drawn HTML
                    elements are not correctly composed when
                    css-transformed with the EGL renderer
           Product: WebKit
           Version: Other
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: Blocker
          Priority: P2
         Component: WebKitGTK
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: llepage at igalia.com
                CC: bugs-noreply at webkitgtk.org

Created attachment 464103

  --> https://bugs.webkit.org/attachment.cgi?id=464103&action=review

Examples of HTML pages showing the bug effects

When displaying an HTML page with dynamically drawn elements (like a WebGL canvas or a video) that are transformed with CSS, some elements are not correctly drawn by the compositor.

This issue happens with the following components and systems:
- WebKitGTK on Wayland desktop with NVidia or Intel cards
- WPE MiniBrowser on desktop with NVidia card (Intel not tested by it would be likely the same as for WebKitGTK)
- wpe-android with the Android emulator and on real phone devices

The issue is systematic, it happens 100% of the time.

At the contrary everything works well and as expected on WebKitGTK on X11 desktop with NVidia card (Intel not tested).

The attached zip file contains 3 web pages presenting the same 3D carousel created using CSS 3D transforms.
The transformed HTML elements are images for the `carousel_images.html` file, videos for the `carousel_video.html` file and WebGL canvas for the `carousel_webgl.html` file.

In all cases the file with static images elements renders correctly. We can see the images all around the carousel facing in the right direction.
For videos and WebGL canvas, some of the elements are not showing at all on EGL based execution of WebKitGTK (or WPE), but are rendering correctly on the non-EGL execution of WebKitGTK.

Thus, everything seems pointing towards an issue with the EGL renderer as it seems to be the common thing to all failling platforms.

The issue can be tested on the same X11 session using a Weston instance. When running the same WebKitGTK executable within an opened Weston window, we can see the buggy transparent elements while running the same executable on the X11 desktop everything renders correctly.

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.webkit.org/pipermail/webkit-unassigned/attachments/20221219/51d1900b/attachment-0001.htm>