I am happy to announce that Vulkan library has finally been integrated into my framework. For the moment nothing complicated, I limited myself to implement a specialization of the Graphics Context that draws simple colored rectangles instead of the images drawn by Cairo library. It's possible to invoke drawing commands with the same degree of complexity and practically identical management of textures, materials and uniforms, at programming interface level.
Each rectangle is associated with a transformation matrix, which is translated into a uniform buffer. It's also possible to rationalize the rendering into multiple layers, allowing the reuse of command buffers with a minimum programming effort.
As you can see from the above image, the 2D GUI based on the graphics context worked quite well. It's possible to drag the windows and see them move on the screen at a high framerate, which is the main purpose for which it's worth bothering the Vulkan libraries.
For the moment there is an implementation of textures and materials, but I have not yet finished the rendering part at shader level. The difficulty lies in the fact that the framework must resolve the material nodes to extract the proper GLSL shader to be converted into SPIRV, create a suitable graphics pipeline and set it before rendering. The next step is to finish this part and make the 2D GUI identical to Cairo version.
Then I can proceed implementing 3D functionality, with a full material management. The main goal is to implement an importer with assimp library and load 3D models. Then I will proceed refining the 3D functionality with a sophiticated engine optimized for modern real-time computer graphics.