GTK4 Toolkit Seeing More Improvements To Its OpenGL Renderer

While GTK 4.0 has been released, there still is major work to look forward to with future GTK4 releases. One area seeing recent and ongoing improvements is with the toolkit's OpenGL renderer.

Even though GTK4 has a Vulkan renderer, the OpenGL renderer is still of interest for cross-platform support particularly for macOS where Vulkan doesn't exist unless employing MoltenVK. There is also still legacy and other cases like the Nouveau driver stack where Vulkan isn't available, thus in 2021 working on the OpenGL renderer still pays off.

Christian Hergert at Red Hat has been working on some OpenGL renderer improvements for past GTK 4.0. While still underway, he mentions he has been "retooling" the OpenGL renderer and is seeing a "healthy bump" in the performance on macOS.

It's getting far enough that I don't mind mentioning I've been retooling the OpenGL renderer for GTK 4 which now tracks all uniform and attachment state to minimize overhead. I'm seeing a healthy bump in FPS on macOS where this matters (cause Mesa rocks on Linux).

— Christian Hergert 👣 (@hergertme) January 22, 2021

Hergert went on to add in a follow-up twet that this OpenGL renderer work preps the infrastructure for batch reordering as another performance win. This also might open the door for getting threaded OpenGL working with GTK. So good things to the GTK4 OpenGL support are still certainly happening in 2021.