Add nanovg bindings

[Spasi]

https://github.com/memononen/nanovg

[dustContributor]

Ohhh, core OpenGL backend. Nice.

[Spasi]

I had a better look at nanovg and even though the code is very clean and sensible (for a C project), it basically requires something like GLEW for the OpenGL backends to work. There's also no support for selecting the exact OpenGL version at runtime, it must be a (native-)compile-time decision.

I don't see a viable approach, other than porting nanovg_gl.h to Java/LWJGL. It doesn't look particularly hard, but I'm not looking forward to it either.

Please post here if you're interested, I'd like to decide whether I should do this before the 3.0.0 release or postpone it.

[kappaOne]

I'd recommend focusing on getting the 3.0 release done first, once the core and basic bindings (GLFW, OpenGL and OpenAL) are done/released then the rest can be added in later releases (like in 3.1). I'd go with a release early, release often, approach.

[dustContributor]

I'm with kappa.

EDIT: Not physically 😝

[Spasi]

I've actually started work on this. NanoVG has several structs, both in the public and the internal API (for the rendering backend) and I decided it is a great opportunity to validate LWJGL's struct API. I'm happy with its current state, but I haven't had experience with how it "feels" in a complex environment and implementing the NanoVG backend is complex enough.

I've done a few fixes and improvements that will be pushed soon, so this is useful already.

[Spasi]

I had a working Java back-end for this, but it was too slow (30-40% slower than the native implementation) due to C-to-Java callback overhead. It wasn't all for nothing though, LWJGL got improved in the process.

The implementation that got committed uses the native back-end, but with important changes (which is a first for LWJGL). The good news is that it's fast and will probably require less maintenance than the Java solution.

[kappaOne]

really nice work, looks awesome especially for game gui's.