(RFC) Allocator pattern

[iwoplaza]

It's very easy to run out of fixed binding slots. The solution is usually to group data together wherever possible. If we're using many shader libraries that need to allocate some data (like perlin noise cache), they all would have to allocate their own data (which quickly uses up bindings), or defer that allocation to the user. I think an allocator pattern might be a good solution that makes things easy by default (a default allocator provided by us), but doesn't restrict use of the library.

// allocator.ts (in typegpu/common)
interface AllocatedUniform<T extends d.AnyData> {
  write(value: d.Infer<T>): void;
  readonly $: d.InferGPU<T>;
}

interface Allocator {
  allocateUniform<T extends AnyData>(dataType: T): AllocatedUniform<T>;
  // ...
}

// lib.ts
interface LibOptions {
  allocator: common.Allocator<T>;
}

export function lib({ allocator }: LibOptions) {
  const timeUniform = allocator.allocateUniform(d.f32);
  // ...
}

// main.ts
import { lib } from './lib.ts';

const allocator = common.defaultAllocator(root);

const foo = lib({ allocator });

The default allocator could, for example, pack all uniforms into a single struct

[aleksanderkatan]

Neat idea. Maybe in libs we should make this argument optional by default, and retrieve common.defaultAllocator(root) if missing?

Does common.defaultAllocator(root) create a new allocator each time or does it keep returning the same one?

Do you see any other potentially useful types of allocators?

[cieplypolar]

IMO, common.defaultAllocator(root) should return new allocator every call. I am also wondering, what methods apart from the allocateUniform could be included within Allocator interface.

[aleksanderkatan]

What about branch pruning and multiple resolutions? Sometimes, some of the AllocatedUniforms will be unused, will we always generate the same struct containing all of those? Or will we prune the fields?

[cieplypolar]

Generally, I really like this idea. Definitely, this will reduce binding usage. I am concerned about the following scenerio:

• user creates allocator
• allocates some unifroms
• resolves shader
• allocates more uniforms

What would happen?

• error?
• new struct?