GTK introduces new 'unified' renderers with a focus on Vulkan API support

GTK, the popular toolkit for writing modern applications, has disclosed the integration of their fresh “unified” rendering code, primarily aimed at Vulkan API support. This model is designed to parallel Vulkan APIs, incorporating certain abstractions to accommodate the variations between Vulkan and GL.

Contrasting with the previous GL renderer, the newly introduced “unified” renderers are expected to stand out in antialiasing, fractional scaling, arbitrary gradients with up to six color stops, and dmabuf support and graphics offloading. Nonetheless, these renderers do not support glshader nodes. Fortunately, the need for glshader nodes has diminished as GTK has incorporated new features post its 4.0 version, such as mask nodes and support for straight-alpha textures.

While the new renderers utilize graphics drivers in unique ways, this opens up the possibility of driver-related issues. The speed of the new renderers has not surpassed the old GL renderer yet, which is heavily optimized for speed and uses simpler shaders. With time, the new rendering code is likely to gain speed. Interestingly, the Vulkan renderer is already showing potential, nearly matching and sometimes exceeding the old GL renderer in certain informal benchmarks.

In the recently launched 4.13.6 snapshot, the NGL renderer has been established as the new default. However, the Vulkan renderer has not been made the default due to its lagging behind the GL renderers in certain application integration aspects. GTK plans to address the current issues in the foreseeable future and will then reconsider the default renderer decision.