Porting to Rust

[mmmoli]

Hi there 👋

Huge fan of this lib and all the hard work done.

Out of respect for the project, I thought I'd try and gradually port it to rust under the same licence.

Any tips on where to start? I was thinking inspect or something?

Thanks

[donmccurdy]

Hi @mmmoli! That sounds like a great project, no objections from me! I'm not a lawyer, but as far as I'm concerned you're welcome to choose whatever license you think is appropriate for the port.

As far as where to start, I made two fairly important decisions early in this project:

1. Users of the library would be able to define their own extensions
2. Most of the long-term time and effort would be spent implementing various operations on glTF data, and so spending time up front making it easier/faster to write those operations would pay off

Lots of other decisions stem from these. With that said —

You'll want to decide before implementing too many operations (like inspect(), draco(), etc.) what the "things" are that functions operate on. The Concepts page explains which glTF concepts are exposed in this library's public API, and which are internalized. Those concepts are implemented by a property graph. When this code runs ...

import { listTextureSlots } from '@gltf-transform/functions';

const slots = listTextureSlots(document, texture);
// → ['occlusionTexture', 'metallicRoughnessTexure']

... it is searching up the graph for materials and material extensions holding references to the given texture. There are a lot of similar operations in the library. I'm not sure what an Rust-friendly implementation of a property graph would look like — it might be a bit different from my implementation, which caters to TypeScript's type checking system.

If you look at any of the data classes (material.ts is a good example), each is defining public getters/setters that internally call the property graph APIs. I'd suggest starting by having a look at those decisions, and adapting them to Rust and to your ideas however makes the most sense to you. Best of luck and feel free to post questions whenever. 🙂