deno_webgpu

deno_webgpu (deno_webgpu/) is the WebGPU bindings for the Deno JavaScript runtime. It's vendored into the wgpu repository so changes to wgpu-core and to Deno's WebGPU surface stay in lockstep.

Purpose

• Implement the WebGPU JavaScript API (navigator.gpu, GPUDevice, GPUBuffer, ...) on top of wgpu-core.
• Provide the runtime surface that Deno's CTS pipeline drives.
• Stay close enough to the WebGPU IDL that browsers and Deno agree on what each method does.

Directory layout

deno_webgpu/
├── Cargo.toml
├── LICENSE.md
├── README.md
├── 00_init.js              Deno bootstrap glue
├── 01_webgpu.js            ~23 KB — WebGPU JS surface
├── 02_surface.js           ~1 KB — surface-related glue
├── adapter.rs              ~15 KB
├── bind_group.rs / bind_group_layout.rs
├── buffer.rs
├── byow.rs                 "bring your own window" surface support (~10 KB)
├── command_buffer.rs / command_encoder.rs
├── compute_pass.rs / compute_pipeline.rs
├── device.rs               ~30 KB
├── error.rs
├── lib.rs
├── pipeline_layout.rs
├── query_set.rs
├── queue.rs
├── render_bundle.rs / render_pass.rs / render_pipeline.rs
├── sampler.rs
├── shader.rs
├── surface.rs
├── texture.rs              ~21 KB
└── webidl.rs               WebIDL conversions

The split mirrors wgpu-core's layout: every WebGPU object gets its own .rs file plus the IDL/*.js glue.

How it works

graph LR
    UserJS[Deno user JS] -->|navigator.gpu| WGJS[01_webgpu.js]
    WGJS -->|deno_core ops| Bridge[deno_webgpu Rust]
    Bridge -->|Id-based calls| Core[wgpu-core::Global]
    Core --> Hal[wgpu-hal]
    Hal --> Driver[Vulkan/Metal/DX12/GL]

The JS glue translates ECMAScript objects to op calls; the Rust glue calls into wgpu-core::Global using its FFI-shaped API. Errors flow back through Deno's JsError machinery.

Notable bits

• byow.rs — "bring your own window" lets a user pass a window handle from outside Deno (for example, when embedding Deno in a Rust application that owns the window). Surface this through 02_surface.js.
• webidl.rs — WebIDL-style coercions: numeric clamping, dictionary defaulting, sequence handling. Mirrors the WebGPU IDL.
• error.rs — central place where wgpu-core errors map to JS errors. Important for getting CTS error-paths right.

Integration points

• Above: cts_runner (in this repo) and the standalone Deno binary downstream.
• Below: wgpu-core, plus deno_core, deno_features, deno_console, deno_url, deno_web, deno_webidl. Versions are pinned in the root Cargo.toml.

When to edit

• A WebGPU IDL change — usually requires updates here, in wgpu-core, and in 01_webgpu.js.
• A bug fix that only manifests through Deno (Deno-only path) — keep in mind AGENTS.md's rule: only fix Deno bindings if the issue is Deno-specific. If it would also apply to Firefox or the wgpu Rust API, fix it in wgpu-core instead.

Tests

Deno bindings are exercised primarily through the WebGPU CTS via cts_runner (see cts_runner).