maintainer-feedback requested: [Bug 256333] x11-toolkits/gtk40: enable VULKAN by default

From: <bugzilla-noreply_at_freebsd.org>
Date: Tue, 01 Jun 2021 12:00:52 UTC
Bugzilla Automation <bugzilla@FreeBSD.org> has asked freebsd-desktop (Team)
<desktop@FreeBSD.org> for maintainer-feedback:
Bug 256333: x11-toolkits/gtk40: enable VULKAN by default
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=256333



--- Description ---
Vulkan is a non-default rendering backend. Upstream builds it by default if
dependencies are found. Vulkan in Gtk4 maybe useful for consumers that already
use Vulkan e.g., multimedia, emulators, games. In general, OPENGL + VULKAN are
similar to X11 + WAYLAND, both are going to coexist for years.

# Need mesa-devel for overlay due to bug 250304
$ pkg install gtk4 mesa-dri mesa-devel
$ VK_INSTANCE_LAYERS=VK_LAYER_MESA_overlay GSK_RENDERER=vulkan gtk4-demo

https://docs.gtk.org/gtk4/running.html