Foreign Function/Memory API (aka Project Panama) Support?

[gudenau]

Description

With the new FFI APIs in preview in Java 19, it would be nice to have LWJGL support. The new FFI APIs are supposed to be faster than JNI already and should hopefully have fewer breaking API changes than the incubator releases of Java 18 and earlier.

There are methods that allow you to used direct NIO buffers and some methods that existing LWJGL tooling may be able to hook into without too much effort.

[octylFractal]

See #609

[gudenau]

That didn't show up in the issues or PRs when I searched, funky.

[Spasi]

Hey @gudenau,

Migrating LWJGL to Panama will be a top priority when the time is right. You'll know it's happening when development on LWJGL 4 begins.

The current plan is to have a first working build when JDK 20 is released. It will be an alpha/beta build and there will be a long testing period after that. Note that:

• Valhalla is still not close to being available, or at least in incubation. With Panama only, LWJGL 4 would be almost the same experience as LWJGL 3 from the user perspective (just replace NIO buffers with MemorySegment).
• The Panama Foreign API in JDK 19 is already obsolete. E.g. the MemoryAddress class, which is a big part of the 19 API, has been removed in 20.
• The performance improvement alone does not justify an early move to Panama. Downcall performance is basically identical to JNI, minus the overhead of two extra parameters. Upcall performance is indeed better, but not many applications care about that.

[gudenau]

Interesting, I was under the impression that preview features were not supposed to have such massive API changes where incubator APIs could.

My bad.