Bug 176718 - [GTK][X11] Windy.com shows always straight wind lines
Summary: [GTK][X11] Windy.com shows always straight wind lines
Alias: None
Product: WebKit
Classification: Unclassified
Component: WebKitGTK (show other bugs)
Version: WebKit Local Build
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Miguel Gomez
Depends on:
Reported: 2017-09-11 12:07 PDT by Carlos Alberto Lopez Perez
Modified: 2017-10-24 05:06 PDT (History)
9 users (show)

See Also:

on the left minibrowser on x11, on the right minibrowser on weston/wayland (1.35 MB, image/png)
2017-09-11 12:08 PDT, Carlos Alberto Lopez Perez
no flags Details
Patch (5.18 KB, patch)
2017-10-24 02:55 PDT, Miguel Gomez
no flags Details | Formatted Diff | Diff

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Description Carlos Alberto Lopez Perez 2017-09-11 12:07:46 PDT
This is something really strange,

If you open this website https://www.windy.com/?18.177,-67.577,4 with the WebKitGTK+ minibrowser you see it ok (like on other browsers) if you are running Wayland. But under X11 the wind lines look all wrong (always straight lines that don't make any sense)

See the attached image, on the left the MB on X11, on the right the MB on Weston on X11. Both built on the same revision: r221865
Comment 1 Carlos Alberto Lopez Perez 2017-09-11 12:08:35 PDT
Created attachment 320452 [details]
on the left minibrowser on x11, on the right minibrowser on weston/wayland
Comment 2 Carlos Garcia Campos 2017-09-11 22:51:21 PDT
Maybe it's GLX issue, could you try with X11 but using EGL?
Comment 3 Miguel Gomez 2017-10-24 02:16:25 PDT
What happens here is that the page uses WebGL, and it's using a texture with GL_LUMINANCE_ALPHA format. This format is deprecated when using an OpenGL core profile. When using glx we use a 3.2 core profile if available, so the format is wrong and the rendering is buggy. But when using EGL we don't request an OpenGL version, so we get an older version that still supports the format and the rendering works.

The fix for this is easy, just backing GL_LUMINANCE_ALPHA with the appropriate format for a core profile. But at some point we should look into requesting a core profile for EGL as well. From what I read, in order to do this we require EGL 1.5 or EGL 1.4 and the extension EGL_KHR_create_context. I'll open a new bug to handle this.
Comment 4 Miguel Gomez 2017-10-24 02:55:23 PDT
Created attachment 324663 [details]
Comment 5 WebKit Commit Bot 2017-10-24 05:06:17 PDT
Comment on attachment 324663 [details]

Clearing flags on attachment: 324663

Committed r223887: <https://trac.webkit.org/changeset/223887>
Comment 6 WebKit Commit Bot 2017-10-24 05:06:18 PDT
All reviewed patches have been landed.  Closing bug.