lineiform VS rs_pbrt

Sounds similar to lineiform. Which isn't all that stable or actively developed, but it is a cute approach to writing a meta-jit in rust. It's a weird approach, but IMO it's worth more experimentation.

Working on Lineiform, my meta-JIT library, some more.

In response to Cranelift, switching to my own Tangle IR won't be using Cranelift at all (it uses raw dynasm-rs for emitting instructions). I go into a bit in https://github.com/chc4/lineiform/issues/19, but Cranelift specifically has some rules about iflags, the type they use to conceptualize processor flags effects (e.g. add's carryout or overflow). You can only have one iflags value live at a time, and it can't overlap with any other math operation. This is a problem because the x86 we're lifting doesn't always follow that rule, so if we just emit Cranelift as we go it will panic and say we built an invalid function.

I go into a bit in https://github.com/chc4/lineiform/issues/19, but it's less a problem with its optimizer and more a problem with its IR constraints. Cranelift specifically has some rules about `iflags`, the type they use to conceptualize processor flags effects (e.g. add's carryout or overflow). You can only have one `iflags` value live at a time, and it can't overlap with any other math operation. This is a problem because the x86 we're lifting doesn't always follow that rule, so if we just emit Cranelift as we go it will panic and say we built an invalid function.

The iflags design in general is kinda awkward too, and was being rethought a few months ago when I was first getting this working; I think they're planning on redesigning the add carryout interface and things to be slightly more streamlined. I suspect that any redesigned interface will have similar problems with mismatch between what I want from Cranelift and what 90% of other uses of Cranelfit want, though, and so I decided to just make my own IR instead.

Working on the codegen backend for Lineiform again. I sketched out a plan on how to implement register allocation in a way that hopefully doesn't have horrible behavior in the majority of cases, and implemented ~half of it last week, and hopefully I'll implement the other half and instruction scheduling this week.

Yup, https://github.com/chc4/lineiform. It's not usable at all yet - I was building it on top of Cranelift, which turned out to be a fairly bad idea, so I'm going to have to essentially rewrite all of it with my own codegen backend I think. I've been hacking on it on and off but it's been much slower progress due to work (and writing a codegen backend is hard...)

I got struck by either a very dumb or very good idea a few days ago, and finally have a working (minimal) proof-of-concept for it: Lineiform is a meta-JIT library to nearly automatically get an optimizing method JIT from a Rust interpreter. It does dynamic recompilation on closures by lifting from x86 to Cranelift IR for runtime function inlining and constant propagation.

I just released a first version of blend_info on crates.io. At some point I was working on a similar project on codeberg and I kind of hacked that into rs-pbrt to be able to use some binary Blender .blend files directly as input for my physically based renderer. The executable for that is called parse_blend_file file and details (or a video about it) can be found here. Anyway, the new crate should help parsing any Blender file (independent of the version) and extract information you like to use, kind of cherry picking stuff. I will use the library in a future version of parse_blend_file (as a prove of concept) but want to involve other people early, because they can help me defining a re-usable library, which can be used for many things, not just my renderer. I also started to use sourcehut and investigated how to use CI (building currently for Debian) there, provide mailing lists, and use the (project based) ticket system. Both projects and activity around it can be found here. Most likely I will work on documentation and maybe a blog post about how to use blend_info next. Try to register for one of the mailing lists if you want to contribute and/or create a ticket ...

If somebody is interested in helping with this issue, there is something to learn from the artistic side (Blender users) as well as from the programming side (Rust coders).

https://www.rs-pbrt.org/ - Physically based rendering (PBR) with Rust

Big thanks to wahn/rs_pbrt: Rust crate to implement a counterpart to the PBRT book's (3rd edition) C++ code. See also https://www.rs-pbrt.org/about ... (github.com) and abusch/rustracer: A toy raytracer written in Rust based on PBRT (github.com) which where helpful as references.