feat(director): add bounded scene data packs and placement

src/scenes/dataPacks/geometry.js

@@ -0,0 +1,73 @@
+import * as Cesium from 'cesium';
+import { decodePackGeoJSON } from '../../director/packs/geojson.js';
+const xyz = (p) => Cesium.Cartesian3.fromDegrees(...p);
+
+/** Render a bounded geometry pack in owned batches; no asynchronous entity geometry or update loop. */
+export function renderPackGeometry({ asset, pack }, handle) {
+  if (!['application/json', 'application/geo+json'].includes(asset.mimeType))
+    throw new Error('Expected GeoJSON');
+  const features = decodePackGeoJSON(asset.bytes);
+  const polygons = [];
+  let lines;
+  for (const feature of features) {
+    const id = { packId: pack.id, featureId: feature.id };
+    if (feature.type === 'Point')
+      handle.add({
+        name: `${pack.id} / ${feature.id}`,
+        position: xyz(feature.coordinates),
+        point: {
+          pixelSize: 12,
+          color: Cesium.Color.CYAN,
+          outlineColor: Cesium.Color.BLACK,
+          outlineWidth: 2,
+        },
+      });
+    else if (feature.type === 'LineString') {
+      if (!lines) {
+        lines = new Cesium.PolylineCollection();
+        handle.primitive(lines);
+      }
+      lines.add({
+        id,
+        positions: feature.coordinates.map(xyz),
+        width: 4,
+        material: Cesium.Material.fromType('Color', {
+          color: Cesium.Color.CYAN,
+        }),
+      });
+    } else
+      polygons.push(
+        new Cesium.GeometryInstance({
+          id,
+          geometry: new Cesium.PolygonGeometry({
+            polygonHierarchy: new Cesium.PolygonHierarchy(
+              feature.coordinates[0].map(xyz),
+              feature.coordinates
+                .slice(1)
+                .map((ring) => new Cesium.PolygonHierarchy(ring.map(xyz))),
+            ),
+            perPositionHeight: true,
+            vertexFormat: Cesium.PerInstanceColorAppearance.VERTEX_FORMAT,
+            arcType: Cesium.ArcType.GEODESIC,
+          }),
+          attributes: {
+            color: Cesium.ColorGeometryInstanceAttribute.fromColor(
+              Cesium.Color.CYAN.withAlpha(0.35),
+            ),
+          },
+        }),
+      );
+  }
+  if (polygons.length)
+    handle.primitive(
+      new Cesium.Primitive({
+        asynchronous: false,
+        geometryInstances: polygons,
+        appearance: new Cesium.PerInstanceColorAppearance({
+          translucent: true,
+          flat: true,
+          closed: false,
+        }),
+      }),
+    );
+}