[RFC] Fake accessing objects in WGSL strings

[iwoplaza]

Currently, if we have resources/functions grouped into an object, the only way to access them in WGSL strings it to pass in every resource one by one.

const group = {
  a: tgpu.fn([]).does(/* ... */),
  b: tgpu.fn([]).does(/* ... */),
};

const foo = tgpu.fn([])
  .does(/* wgsl */`() {
    group.a();
    group.b();
  }`)
  .$uses({ group });

We could do this by checking what type of value group is when applying externals, and if it's a plain JS object, seeing if there are any property accesses to the right.

[mhawryluk]

Great idea!

[iwoplaza]

@reczkok Thoughts? 🧠

[reczkok]

Would something like this work?

const group = {
  a: tgpu.fn([]).does(/* ... */),
  b: tgpu.fn([]).does(/* ... */),
};

const foo = tgpu.fn([])
  .does(/* wgsl */`() {
    a();
    b();
  }`)
  .$uses({ ...group });

[iwoplaza]

Depends! It works for this use case, but examples like this and layout.bound could be made a bit more readable thanks to this:

const layout = tgpu
  .bindGroupLayout({
    lightSource: { uniform: LightSource },
    sampling: { sampler: 'filtering' },
    bgTexture: { externalTexture: {} },
  });

const main = tgpu.fn([])
  .does(/* wgsl */`() {
    layout.bound.sampling;
    // ...
  }`)
  .$uses({ layout });

I was trying to implement some game engine niceties a while back, and the lack of this feature hindered me a lot.
Basically, with this feature, the actual property access can happen in context of a resolution, while without it, we have to perform the property get outside of a resolution. If the resource we are accessing is GPU-only, then it poses a problem.

[iwoplaza]

Implemented in #780, released in 0.3.1 🎉