[ari__]

I'm unsure how I feel about classifying an entire game engine as middleware. For most engines (Godot included!) building your code for a different platform is as easy as changing your target in a dropdown menu.

I'm also deeply curious as to exactly how many indie game developers are writing code that interfaces directly with these low level systems and graphics APIs. In my experience, building cross platform games (I've shipped from Unity, Unreal, Godot, and XNA/MonoGame) is trivial and the framework handles 100% of the complexity of porting. From the sounds of this comment thread, everybody is writing their game in raw shader language and then having to port that to Vulkan or OpenGL.