RFR: 8329820: [Linux] Prefer EGL over GLX [v19]

[Thiago Milczarek Sayao]

On Wed, 9 Oct 2024 13:27:02 GMT, Thiago Milczarek Sayao <tsayao at openjdk.org> wrote:

>> Wayland implementation will require EGL. 
>> 
>> EGL works with Xorg as well. The idea is to be EGL first and if it fails, fallback to GLX. A force flag `prism.es2.forceGLX=true` is available.
>> 
>> 
>> See:
>> [Switching the Linux graphics stack from GLX to EGL](https://mozillagfx.wordpress.com/2021/10/30/switching-the-linux-graphics-stack-from-glx-to-egl/)
>> [Prefer EGL to GLX for the GL support on X11](https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/3540)
>
> Thiago Milczarek Sayao has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Remove unused externs
>  - Destroy DrawableInfo properly

Makes sense to only use EGL when enabled, at least until it's mature and known to work for most setups - I can do this change.

Wayland would require EGL, but it works fine with Xorg for quite some time. (I would say Ubuntu 16.04, but I must check it to be sure).

Gtk4 does prefer EGL on X11:
https://gitlab.gnome.org/GNOME/gtk/-/blob/main/gdk/x11/gdkdisplay-x11.c

See `gdk_x11_display_init_gl_backend`.

Gtk3 uses GLX for X11.

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PR Comment: https://git.openjdk.org/jfx/pull/1381#issuecomment-2433155578