Hi adamio, it's still early yet to know what will happen with Vulkan - that's another additional factor that makes it kind of unwise for me to jump in with Metal support right now.

But definitely the biggest barrier for me is actually OS X support - meaning all the already released versions of OS X. From what I have seen so far, Metal will only be supported on 10.11, probably not on any previous version. So if I were to only target that for the graphics API to use, MoI would not be usable on earlier OS X versions at all. That's an extremely significant disadvantage compared to targeting OpenGL, which does work on all versions of OS X.

If you can find out if Metal will be supported on earlier versions of OS X, that could make it a lot more interesting for me to look into.

re:
> Some examples from early adapters. <...>

Well, I hope you're aware that the Foundry and Adobe have considerably more developers working for them than I do. That makes it feasible for them to work on Metal as a side engine instead of their only supported one. Please keep in mind that I'm only one single person doing all the development work for MoI and that makes it difficult for me to do exploratory side work, I need to focus my efforts on the main line work that will be used by the most people.

- Michael