City-Lifeline-Cockpit/tools/city-massing/make-root-anchor.mjs

// Build a valid empty-scene GLB so Cesium can traverse a contentless spatial root reliably.
import { Buffer } from 'node:buffer'
import { mkdirSync, writeFileSync } from 'node:fs'
import { resolve } from 'node:path'
const json = Buffer.from(JSON.stringify({
    asset: { version: '2.0', generator: 'ticket35 root anchor' },
    scene: 0,
    scenes: [{ nodes: [] }],
}))
const padded = Buffer.concat([json, Buffer.alloc((4 - json.length % 4) % 4, 0x20)])
const header = Buffer.alloc(12)
header.write('glTF')
header.writeUInt32LE(2, 4)
header.writeUInt32LE(12 + 8 + padded.length, 8)
const chunk = Buffer.alloc(8)
chunk.writeUInt32LE(padded.length)
chunk.write('JSON', 4)
const glb = Buffer.concat([header, chunk, padded])
if (glb.readUInt32LE(8) !== glb.length || glb.toString('ascii', 16, 20) !== 'JSON') {
    throw new Error('Invalid GLB header')
}
JSON.parse(glb.toString('utf8', 20, 20 + glb.readUInt32LE(12)))
for (const dir of ['tools/city-massing/district/lod-preview', 'tools/city-massing/city/regular-estate/lod-preview', 'tools/city-massing/city/oldtown/lod-preview']) {
    mkdirSync(resolve(dir), { recursive: true })
    writeFileSync(resolve(dir, 'root-anchor.glb'), glb)
}
console.log({ bytes: glb.length, outputs: 3 })