City-Lifeline-Cockpit/tools/city-massing/prepare-oldtown-dem.mjs

// Expand old-town candidates into actual ENU footprints and bind them to original DEM samples.
import { readFileSync, writeFileSync } from 'node:fs'
import { Cartesian3, Cartographic, Matrix4, Transforms } from 'cesium'
const dir = 'tools/city-massing/city/oldtown/',
    plan = JSON.parse(readFileSync(dir + 'plan.json'))
const origin = { lon: 110.395, lat: 28.454 },
    transform = Transforms.eastNorthUpToFixedFrame(Cartesian3.fromDegrees(origin.lon, origin.lat)),
    inverse = Matrix4.inverseTransformation(transform, new Matrix4())
const toLocal = (lon, lat) => Matrix4.multiplyByPoint(inverse, Cartesian3.fromDegrees(lon, lat), new Cartesian3())
const toGeo = (q) => {
    const c = Cartographic.fromCartesian(Matrix4.multiplyByPoint(transform, new Cartesian3(...q), new Cartesian3()))
    return { lon: (c.longitude * 180) / Math.PI, lat: (c.latitude * 180) / Math.PI }
}
const modules = []
const samples = []
for (const b of plan.buildings) {
    const center = toLocal(b.lon, b.lat)
    const u = [Math.cos(b.heading), Math.sin(b.heading)],
        v = [-u[1], u[0]]
    const corners = [
        [-b.width / 2, -b.depth / 2],
        [b.width / 2, -b.depth / 2],
        [b.width / 2, b.depth / 2],
        [-b.width / 2, b.depth / 2],
    ].map(([x, y]) => [center.x + u[0] * x + v[0] * y, center.y + u[1] * x + v[1] * y, 0])
    const pts = [...corners, [center.x, center.y, 0]]
    // Interior samples at 5 m spacing so terrain relief is measured across the real footprint,
    // not inferred from four corners.
    const cols = Math.max(1, Math.ceil(b.width / 5))
    const rows = Math.max(1, Math.ceil(b.depth / 5))
    for (let row = 0; row <= rows; row++)
        for (let col = 0; col <= cols; col++) {
            const lx = -b.width / 2 + (b.width * col) / cols
            const ly = -b.depth / 2 + (b.depth * row) / rows
            pts.push([center.x + u[0] * lx + v[0] * ly, center.y + u[1] * lx + v[1] * ly, 0])
        }
    const sampleIndices = pts.map((p) => {
        samples.push({ ...toGeo(p), building: b.id })
        return samples.length - 1
    })
    modules.push({
        ...b,
        sourceId: b.sourceId || b.id,
        center: toGeo([center.x, center.y, 0]),
        centerENU: [center.x, center.y, 0],
        footprintENU: corners,
        archetype: b.archetype || 'house',
        sampleIndices,
    })
}
const out = {
    ...plan,
    origin,
    transform: Matrix4.toArray(transform),
    modules,
    samples,
    source: 'residential masks + bounded road/water exclusion + direct original DEM corners/center',
    disclaimer: plan.disclaimer + ' Terrain seating is validated separately against the original quantized mesh.',
}
writeFileSync(dir + 'plan.json', JSON.stringify(out, null, 2))
console.log({ modules: modules.length, samples: samples.length })