build-smlib-wasm.mjs: tracked (root .mjs files are ignored unless listed)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: RandoTechNerd

.gitignore

@@ -47,6 +47,7 @@ viewer/locked-key.js
 # the LAST matching rule wins.
 /*.mjs
 !/build-site.mjs
+!/build-smlib-wasm.mjs
 
 # Scratch stashes of model code saved while iterating on an example. The
 # example itself lives in examples/; these are the drafts.

build-smlib-wasm.mjs

@@ -0,0 +1,57 @@
+// Stages the SMLib kernel as WebAssembly for the website:
+//   ../smlib-wasm (github.com/RandoTechNerd/smlib-wasm)  ->  vendor/brep-kernel-smlib/
+//
+// The same SMLib (from NVIDIA's open-source usd-brep) the desktop alpha runs
+// as a native addon, compiled with Emscripten in its own repo. The worker
+// (viewer/kernel-worker.js) runs it behind native/nvidia-kernel/adapter.cjs,
+// exactly as the desktop does, when the kernel picker says "nvidia". The
+// result is committed (as vendor/brep-kernel-rust is), so a site build needs
+// no Emscripten.
+//
+//   node build-smlib-wasm.mjs           copy the smlib-wasm repo's dist/ here
+//   node build-smlib-wasm.mjs --build   rebuild it there first (needs its Emscripten SDK)
+//
+// SMLIB_WASM=<dir> points at the smlib-wasm checkout (default: ../smlib-wasm
+// beside this repo's main checkout).
+
+import { execFileSync } from "node:child_process";
+import { copyFileSync, existsSync, mkdirSync, readFileSync, statSync, writeFileSync } from "node:fs";
+import { dirname, join, resolve } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const here = dirname(fileURLToPath(import.meta.url));
+const candidates = [process.env.SMLIB_WASM, join(here, "..", "smlib-wasm"), join(here, "..", "..", "smlib-wasm")].filter(Boolean);
+const SRC = candidates.map((p) => resolve(p)).find((p) => existsSync(join(p, "src", "api.mjs")));
+if (!SRC) {
+  console.error(`build-smlib-wasm: no smlib-wasm checkout (looked in ${candidates.join(", ")}); set SMLIB_WASM`);
+  process.exit(1);
+}
+const OUT = join(here, "vendor", "brep-kernel-smlib");
+
+if (process.argv.includes("--build")) execFileSync(process.execPath, ["build.mjs"], { cwd: SRC, stdio: "inherit" });
+for (const f of ["smlib.mjs", "smlib.wasm"]) {
+  if (!existsSync(join(SRC, "dist", f))) { console.error(`build-smlib-wasm: ${SRC}/dist/${f} is missing: node build.mjs there first (or --build)`); process.exit(1); }
+}
+
+mkdirSync(OUT, { recursive: true });
+copyFileSync(join(SRC, "dist", "smlib.mjs"), join(OUT, "smlib.mjs"));
+copyFileSync(join(SRC, "dist", "smlib.wasm"), join(OUT, "smlib.wasm"));
+copyFileSync(join(SRC, "LICENSE"), join(OUT, "LICENSE"));
+copyFileSync(join(SRC, "THIRD_PARTY_NOTICES.md"), join(OUT, "THIRD_PARTY_NOTICES.md"));
+// api.mjs sits beside the module here, not one folder up
+writeFileSync(join(OUT, "api.mjs"), readFileSync(join(SRC, "src", "api.mjs"), "utf8").split('"../dist/smlib.mjs"').join('"./smlib.mjs"'));
+
+let commit = "unknown";
+try { commit = execFileSync("git", ["rev-parse", "--short", "HEAD"], { cwd: SRC }).toString().trim(); } catch { /* not a git checkout */ }
+writeFileSync(join(OUT, "README.md"), `# vendor/brep-kernel-smlib
+
+The SMLib B-rep kernel, based on NVIDIA's open-source usd-brep (SMLib +
+SM_API, v1.0.1, Apache-2.0), compiled to WebAssembly in
+https://github.com/RandoTechNerd/smlib-wasm (commit ${commit}). Staged here by
+\`node build-smlib-wasm.mjs\`; don't edit these files by hand.
+
+\`api.mjs\` gives the same functions as the desktop's native addon, so
+\`native/nvidia-kernel/adapter.cjs\` runs on it unchanged (see
+viewer/kernel-worker.js). See LICENSE and THIRD_PARTY_NOTICES.md.
+`);
+console.log(`build-smlib-wasm: ${OUT} from ${SRC} @ ${commit} (smlib.wasm ${(statSync(join(OUT, "smlib.wasm")).size / 1e6).toFixed(1)} MB)`);