softmarshmallow · Oct 2, 2026 · Oct 2, 2026
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -38,7 +38,7 @@ jobs:
             .cache/ci/linux-amd64/target/debug/.fingerprint
             .cache/ci/linux-amd64/target/.rustc_info.json
             .cache/ci/linux-amd64/home/.npm
-          key: n3-v1-ubuntu24-linux-amd64-${{ steps.environment.outputs.image }}-${{ hashFiles('Cargo.toml', 'Cargo.lock') }}
+          key: n3-v1-ubuntu24-linux-amd64-${{ steps.environment.outputs.image }}-${{ hashFiles('Cargo.toml', 'Cargo.lock', 'vendor/**') }}
       - name: Check formatting, lint, tooling, and focused regressions
         env:
           N3_CI_FAILURE_ARTIFACTS: "1"
@@ -94,7 +94,7 @@ jobs:
             .cache/ci/linux-amd64/target/debug/.fingerprint
             .cache/ci/linux-amd64/target/.rustc_info.json
             .cache/ci/linux-amd64/home/.npm
-          key: n3-v1-ubuntu24-linux-amd64-${{ steps.environment.outputs.image }}-${{ hashFiles('Cargo.toml', 'Cargo.lock') }}
+          key: n3-v1-ubuntu24-linux-amd64-${{ steps.environment.outputs.image }}-${{ hashFiles('Cargo.toml', 'Cargo.lock', 'vendor/**') }}
       - name: Replay every guide feature and check exact artifacts
         env:
           N3_CI_FAILURE_ARTIFACTS: "1"
@@ -142,7 +142,7 @@ jobs:
             target/debug/build
             target/debug/.fingerprint
             target/.rustc_info.json
-          key: n3-v1-macos15-${{ runner.os }}-${{ runner.arch }}-${{ steps.environment.outputs.platform }}-${{ hashFiles('rust-toolchain.toml', 'Cargo.toml', 'Cargo.lock') }}
+          key: n3-v1-macos15-${{ runner.os }}-${{ runner.arch }}-${{ steps.environment.outputs.platform }}-${{ hashFiles('rust-toolchain.toml', 'Cargo.toml', 'Cargo.lock', 'vendor/**') }}
       - name: Restore the pinned just installation
         id: just
         uses: actions/cache/restore@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
@@ -177,3 +177,100 @@ jobs:
             ~/.cargo/.crates.toml
             ~/.cargo/.crates2.json
           key: ${{ steps.just.outputs.cache-primary-key }}
+
+  wasm:
+    name: WASM lint and browser build
+    runs-on: ubuntu-24.04
+    timeout-minutes: 45
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+      - name: Set up the contributor Node.js version
+        uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
+        with:
+          node-version: "24"
+          package-manager-cache: false
+      - name: Identify the browser build runner
+        id: environment
+        run: |
+          python3 - <<'PY' >> "$GITHUB_OUTPUT"
+          import hashlib
+          import os
+          image = os.environ.get("ImageVersion", "unreported")
+          print(f"platform={hashlib.sha256(image.encode()).hexdigest()}")
+          PY
+      - name: Restore WASM dependencies and build output
+        id: dependencies
+        uses: actions/cache/restore@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
+        with:
+          path: |
+            .cache/cargo/registry/cache
+            .cache/cargo/registry/index
+            target/debug/deps
+            target/debug/build
+            target/debug/.fingerprint
+            target/web/deps
+            target/web/build
+            target/web/.fingerprint
+            target/wasm32-unknown-unknown/debug/deps
+            target/wasm32-unknown-unknown/debug/build
+            target/wasm32-unknown-unknown/debug/.fingerprint
+            target/wasm32-unknown-unknown/web/deps
+            target/wasm32-unknown-unknown/web/build
+            target/wasm32-unknown-unknown/web/.fingerprint
+            target/.rustc_info.json
+          key: n3-v1-wasm-${{ runner.os }}-${{ runner.arch }}-${{ steps.environment.outputs.platform }}-${{ hashFiles('rust-toolchain.toml', 'Cargo.toml', 'Cargo.lock', 'vendor/**') }}
+      - name: Restore pinned browser build tools
+        id: tools
+        uses: actions/cache/restore@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
+        with:
+          path: |
+            ~/.cargo/bin/just
+            ~/.cargo/.crates.toml
+            ~/.cargo/.crates2.json
+            .cache/web-tools/bin/wasm-bindgen
+            .cache/web-tools/.crates.toml
+            .cache/web-tools/.crates2.json
+          key: n3-v1-wasm-tools-just1.46.0-${{ runner.os }}-${{ runner.arch }}-${{ steps.environment.outputs.platform }}-${{ hashFiles('rust-toolchain.toml', 'Cargo.toml') }}
+      - name: Install optional browser tooling using the repository Rust toolchain
+        run: |
+          cargo install just --version 1.46.0 --locked
+          just web-setup
+      # Compile and generate glue on every run. The native lanes continue to
+      # own behavioral tests and exact guide receipts; this job needs no GPU.
+      - name: Lint the WASM target and generate the browser application
+        run: just web-verify
+      - name: Save verified WASM dependencies and build output
+        if: success() && github.event_name == 'push' && github.ref == 'refs/heads/main' && steps.dependencies.outputs.cache-hit != 'true'
+        uses: actions/cache/save@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
+        with:
+          path: |
+            .cache/cargo/registry/cache
+            .cache/cargo/registry/index
+            target/debug/deps
+            target/debug/build
+            target/debug/.fingerprint
+            target/web/deps
+            target/web/build
+            target/web/.fingerprint
+            target/wasm32-unknown-unknown/debug/deps
+            target/wasm32-unknown-unknown/debug/build
+            target/wasm32-unknown-unknown/debug/.fingerprint
+            target/wasm32-unknown-unknown/web/deps
+            target/wasm32-unknown-unknown/web/build
+            target/wasm32-unknown-unknown/web/.fingerprint
+            target/.rustc_info.json
+          key: ${{ steps.dependencies.outputs.cache-primary-key }}
+      - name: Save verified browser build tools
+        if: success() && github.event_name == 'push' && github.ref == 'refs/heads/main' && steps.tools.outputs.cache-hit != 'true'
+        uses: actions/cache/save@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
+        with:
+          path: |
+            ~/.cargo/bin/just
+            ~/.cargo/.crates.toml
+            ~/.cargo/.crates2.json
+            .cache/web-tools/bin/wasm-bindgen
+            .cache/web-tools/.crates.toml
+            .cache/web-tools/.crates2.json
+          key: ${{ steps.tools.outputs.cache-primary-key }}
diff --git a/.oxfmtrc.json b/.oxfmtrc.json
@@ -7,6 +7,7 @@
     "/Cargo.lock",
     "/docs/guide/**",
     "/docs/preview/vendor/**",
+    "/vendor/**",
     "/examples/**",
     "/fixtures/gltf/*/**"
   ]

diff --git a/AGENTS.md b/AGENTS.md
@@ -8,8 +8,8 @@ decision.
 
 ## Product and interaction principles
 
-- Focus on hard-surface mesh modeling. Broader modeling tools, web support, and
-  speculative UX ideas are separate work; do not silently expand a task to add them.
+- Focus on hard-surface mesh modeling. Broader modeling tools and speculative
+  UX ideas are separate work; do not silently expand a task to add them.
 - Keep actions semantic and key bindings separate. UI controls, shortcuts, and
   tutorial replay should reuse the same behavior rather than implement variants.
 - Respect input ownership: text fields, popups, active gestures, and edit sessions
@@ -73,6 +73,12 @@ Keep one application crate until a real consumer and a clear dependency boundary
 justify extraction. Prefer focused modules over speculative crates, public APIs,
 or generic frameworks.
 
+Read [platform boundaries and performance](docs/architecture/platform-boundaries.md)
+before changing host adapters or platform-dependent behavior. Share product
+semantics, keep target selection at module boundaries, and preserve each host's
+execution policy. Browser constraints must not lower the primary native target's
+capabilities, performance policy, or verification baseline.
+
 | Location             | Responsibility                                                        |
 | -------------------- | --------------------------------------------------------------------- |
 | `src/model/`         | Authored documents, units, native text codec, geometry evaluation     |
@@ -108,6 +114,10 @@ The user guide is a primary development and review contract: maintainers give
 feedback on the same narrative and evidence that real users read. Important
 promises must be executable and fail visibly when they drift.
 
+Native and web share one feature UI and user guide. Follow the
+[shared product contract](docs/architecture/platform-boundaries.md#one-product-experience)
+for capability-based availability and the boundary with contributor documentation.
+
 Every guide feature owns one Rust scenario in `src/documentation/scenarios/` and
 one template in `docs/templates/`, registered in
 `src/documentation/features.rs`. Edit those sources; never hand-edit generated

diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -5,21 +5,22 @@ edition = "2024"
 rust-version = "1.95"
 publish = false
 
+[lib]
+crate-type = ["rlib", "cdylib"]
+# This private application library owns the existing single test inventory.
+doctest = false
+
 [[bin]]
 name = "n3"
 path = "src/main.rs"
+test = false
 
 [dependencies]
-alacritty_terminal = "=0.26.0"
 base64 = "0.22.1"
 bytemuck = { version = "1.25.2", features = ["derive"] }
 earcutr = "0.5.0"
 egui = "=0.36.2"
 egui-wgpu = "=0.36.2"
-egui-winit = { version = "=0.36.2", default-features = false, features = [
-  "clipboard",
-  "links",
-] }
 glam = "0.33.11"
 gltf = { version = "1.4.1", default-features = false, features = [
   "utils",
@@ -35,21 +36,68 @@ image = { version = "=0.25.10", default-features = false, features = [
   "png",
   "webp",
 ] }
-libc = "0.2"
-pollster = "1.0.1"
 percent-encoding = "2.3.2"
-rfd = "0.17.2"
 serde = { version = "1", features = ["derive"] }
 serde_json = { version = "1", features = ["float_roundtrip", "raw_value"] }
 sha2 = "0.10.9"
 wgpu = "30.0.1"
 winit = "=0.30.13"
 
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+alacritty_terminal = "=0.26.0"
+egui-winit = { version = "=0.36.2", default-features = false, features = [
+  "clipboard",
+  "links",
+] }
+libc = "0.2"
+pollster = "1.0.1"
+rfd = "0.17.2"
+
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+console_error_panic_hook = "0.1.7"
+egui-winit = { version = "=0.36.2", default-features = false, features = [
+  "links",
+] }
+js-sys = "=0.3.106"
+wasm-bindgen = "=0.2.129"
+wasm-bindgen-futures = "=0.4.79"
+web-time = "1.1.0"
+web-sys = { version = "=0.3.106", features = [
+  "AddEventListenerOptions",
+  "console",
+  "CustomEvent",
+  "CustomEventInit",
+  "Document",
+  "DomRect",
+  "Element",
+  "Event",
+  "EventTarget",
+  "HtmlCanvasElement",
+  "HtmlElement",
+  "Navigator",
+  "Performance",
+  "Storage",
+  "StorageEvent",
+  "WheelEvent",
+  "Window",
+] }
+
 [dev-dependencies]
 tobj = { version = "4.0.5", features = ["use_f64"] }
 
+# egui-winit 0.36.2 implements only the native DroppedFile trait method.
+# Preserve its input integration with a narrow WASM compatibility patch.
+[patch.crates-io]
+egui-winit = { path = "vendor/egui-winit" }
+
 [profile.dev]
 opt-level = 1
 
 [profile.dev.package."*"]
 opt-level = 2
+
+# Keep local browser iteration quick without shipping Rust debug sections.
+[profile.web]
+inherits = "dev"
+debug = false
+strip = "debuginfo"
diff --git a/README.md b/README.md
@@ -99,13 +99,29 @@ Read the illustrated guide in your browser with `just docs` (requires Python 3).
 It opens a local preview of the checked-in documentation; press Ctrl-C in the
 terminal to stop the server.
 
+### Browser baseline
+
+The same Rust editor and viewport also run in a browser through WebAssembly and
+WebGPU. To build and serve the local baseline:
+
+```sh
+just web-setup
+just web
+```
+
+Use a desktop browser with WebGPU available. Native and web use the same
+workspace and [user guide](docs/guide/README.md); unsupported host features are
+omitted. See [development](docs/development.md#browser-build) for setup,
+embedding, and platform limits.
+
 ## Current scope
 
 N3 currently supports object transforms, vertex editing,
 [making a face](docs/guide/make-face.md) from a triangle or a single flat outline,
 and explicit [X-ray selection](docs/guide/xray.md). Broader topology tools,
 edge/face selection, geometry snapping, and sculpting are future work.
-Web support is also deferred.
+The browser build is a technical baseline; full browser and device coverage is
+still under evaluation.
 
 OBJ import focuses on vertex positions and polygon faces. Materials, textures,
 UVs, and authored normals are not preserved, and OBJ export is not implemented.

diff --git a/TODO.md b/TODO.md
@@ -31,7 +31,9 @@ and document the implemented behavior in the executable user guide.
 | Inspector number overflow | Keep each numeric field frame fixed while clipping or scrolling only its value text; egui's `DragValue` currently expands both. |
 | Native accessibility | Wire egui's AccessKit adapter through the native event loop, add polite live announcements for toasts, and verify with VoiceOver. Keyboard focus and widget labels alone do not provide screen-reader announcements. |
 | OS font support | Fonts as document materials; discovery/loading boundary suitable for a later web implementation. Separate from bundled interface fonts. |
-| Initial WASM spike | Prove a minimal browser build and identify platform dependencies before deciding on a full port. |
+| Web platform follow-up | Build on the [WASM browser baseline](docs/development.md#browser-build): browser/device coverage, touch/IME, external asset resource workflows, persistence/recovery, and multiple embedded workspaces. |
+| Native/browser viewport profiling | [Issue #2](https://github.com/gridaco/n3/issues/2): reproduce large-mesh orbit stutter with comparable builds, real browser runs, and stage-level timings. Distinguish shared costs, web-host mistakes, and measured platform constraints before optimizing; follow the WASM baseline delivery. |
+| Linux capture test concurrency | Diagnose allocator aborts and segmentation faults in parallel lavapipe tests, reproduced on the native baseline. The [opt-in CI runner](docs/development.md#verification-and-git-hooks) uses one test thread while retaining every test and exact capture; establish the cause before restoring parallel execution. |
 | Exact macOS 27 guide frame | Replace the approximate static window chrome with measurements from a native macOS 27 N3 capture or Apple's design kit. Evaluate the translucent traffic-light material, highlights, and shadow only if exact mirroring is worth the rendering complexity. |
 
 Existing context: [UX ideas](docs/research/ux-ideas.md),