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flohofwoe 9 hours ago [-]
FWIW, there's a WebGPU extension which 'harmonizes' uniform buffer struct layout with other address spaces, but currently it's only implemented in Chromium-based browsers:
The std140-style layout restrictions are basically a leftover when GPUs used vec4 "register tables" for uniform data.
mkeeter 7 hours ago [-]
Nice, I'll keep an eye on that!
Right now, I'm targeting everything (native / Firefox / Chrome / Safari), so minimizing use of extensions; this also means I get to run head-long into fun cross-platform behavior differences [1][2][3]
> facet is a library for Rust which provides run-time reflection. By annotating your struct with #[derive(facet::Facet)], you get a SHAPE associated type which can be inspected at runtime.
> The core crates give types a SHAPE associated constant with their kind, layout, fields, documentation, attributes, and type-specific operations. facet-reflect builds, reads, and mutates values through those shapes while preserving their invariants.
> Serialization and integration crates build on that reflection layer: JSON, TOML, YAML, MessagePack, Postcard, ASN.1, XDR, CSV, XML, URL-encoded forms, SQLite, Axum, schema generation, structural diffing, and more.
While most of the time you want the memcpy semantics, but I wonder if naga could be used to compute a facet SHAPE from the shader. Maybe it could be used to "serialise" the cpu format to gpu format, without them needing to be padding/repr-compatible (or even field-reorder-compatible!).
Another option of course would be to parse the struct with naga and just always generate the rust counterpart, then it should always be compatible and up-to-date, but then you have codegen in your build step.
brinepot 9 hours ago [-]
Spent too much time debugging alignment issues with Vulkan buffers. WebGPU having good tools like Facet from the start is a huge win.
jauntywundrkind 9 hours ago [-]
This is so good. And it's so absurd how programming languages so frequently treat types as a compile time check. Still. After so so long.
It's great having tools like Facet around to add runtime type information in. I wish TypeScript was seeing progress but there's seemingly no progress or traction in 5 years+, just some early experiments which died out.
Ticket: https://github.com/gpuweb/gpuweb/issues/4973
Caniuse: https://caniuse.com/?search=uniform_buffer_standard_layout
The std140-style layout restrictions are basically a leftover when GPUs used vec4 "register tables" for uniform data.
Right now, I'm targeting everything (native / Firefox / Chrome / Safari), so minimizing use of extensions; this also means I get to run head-long into fun cross-platform behavior differences [1][2][3]
[1] https://github.com/gfx-rs/wgpu/issues/8785
[2] https://bugzilla.mozilla.org/show_bug.cgi?id=1870699
[3] https://github.com/mkeeter/halfspace/issues/1#issuecomment-3...
https://github.com/facet-rs/facet
> The core crates give types a SHAPE associated constant with their kind, layout, fields, documentation, attributes, and type-specific operations. facet-reflect builds, reads, and mutates values through those shapes while preserving their invariants.
> Serialization and integration crates build on that reflection layer: JSON, TOML, YAML, MessagePack, Postcard, ASN.1, XDR, CSV, XML, URL-encoded forms, SQLite, Axum, schema generation, structural diffing, and more.
Side by side comparison with SERDE https://facet.rs/guide/serde/
While most of the time you want the memcpy semantics, but I wonder if naga could be used to compute a facet SHAPE from the shader. Maybe it could be used to "serialise" the cpu format to gpu format, without them needing to be padding/repr-compatible (or even field-reorder-compatible!).
Another option of course would be to parse the struct with naga and just always generate the rust counterpart, then it should always be compatible and up-to-date, but then you have codegen in your build step.
It's great having tools like Facet around to add runtime type information in. I wish TypeScript was seeing progress but there's seemingly no progress or traction in 5 years+, just some early experiments which died out.