Wayland reference compositor Weston 15 with Lua shell and Vulkan renderer

The reference implementation of the Wayland project for a compositor named Weston has been released in version 15. Particularly noteworthy are the easily programmable Lua shell and the new Vulkan renderer.

In a blog post, Collabora developer Marius Vlad summarizes the innovations in Weston 15. About a week ago, he announced the release on the Wayland developer mailing list; the changelog for the last release candidate 5 only includes the version number jump. The Lua shell is new. As the name suggests, it allows interested parties to customize window management and create shells in the popular scripting language Lua without needing to program in C. To provide a starting point, Weston 15 includes an exemplary tiling shell. It can be tried out by calling weston --shell=lua.

The developers also promise “buttery smooth and efficient media playback.” They have perfected the timing of the final frames, which had previously been a problem for Vulkan clients and Wayland. By adding Vulkan extensions, Weston can now use images in a pipeline according to the FIFO principle without the delays that would otherwise occur. In the HDR area, Weston supports additional 10-bit pixel formats such as NV15, NV20, NV30, and P030. However, support for the extensions for color representation and management, which are necessary for HDR video playback, is still a “work in progress.”

New Renderer

The Vulkan renderer is a new component of Weston. However, it is still in the experimental phase, Vlad explains. Developers can work on activating Vulkan drivers without Weston needing to run with an intermediate translation layer like Zink. The Vulkan renderer runs both natively with Direct Rendering Manager (DRM) and with Nested Backends. This means it can run as a window in both Wayland and X11.

The goal is to support the Vulkan 1.0 specification. The Vulkan renderer also comes with clients like “simple-vulkan” or “simple-dmabuf-vulkan.” The Wayland client can use a different API than the Weston compositor. The Vulkan renderer can be tested by calling weston --renderer=vulkan.

Further improvements concern accessibility. For example, different color effects are needed for certain types of color blindness, which the GL renderer must apply. However, at the current stage, these are incompatible with color management and implicitly also with HDR functionality. Developers are working on fixes here, and support for the Vulkan renderer is to be added in a future version.

Vlad also lists further fixes and improvements for those interested, concerning the DRM back-end, the GL renderer, protocols, shells, and tools. The updated software can be found as source code on the Wayland download page. Linux distributions are likely to deliver updated packages shortly, with which Weston 15 can be tested.

In Weston 12, for example, one of the improvements was support for more graphics chips.

(dmk)