perf(models): aircraft models skip Cesium's dynamic environment map (#1366)

Skip per-aircraft dynamic environment maps while retaining default model lighting.

Contribution by @quanticsoul4772.

src/data/aircraftModelLighting.js

@@ -0,0 +1,17 @@
+/**
+ * Lighting options shared by every aircraft 3D model (Flights, Military
+ * Flights, Local ADS-B).
+ *
+ * Cesium gives each Model a dynamic environment map: it renders the sky around
+ * the model and reads the result back from the GPU (`readPixels`) to light it,
+ * when the model is first placed and again when it moves more than 1 km, when
+ * the scene's atmosphere settings change, or every scene hour under sunlight
+ * lighting. Aircraft models take 94% of their surface from the class colour
+ * (`colorBlendAmount`), so that lighting contributes little; without it they
+ * are lit from Cesium's default spherical harmonics. Measured 2026-10-24
+ * (Intel Arc, Google 3D, ~150 models in the scene): GPU per frame at rest
+ * 14.3-14.8 -> 12.1-12.5 ms.
+ */
+export const AIRCRAFT_ENVIRONMENT_MAP_OPTIONS = Object.freeze({
+  enabled: false,
+});

src/data/aircraftModelLighting.test.mjs

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+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { readFileSync } from 'node:fs';
+import { readLayerSource } from '../testSupport/readLayerSource.mjs';
+import { AIRCRAFT_ENVIRONMENT_MAP_OPTIONS } from './aircraftModelLighting.js';
+
+/**
+ * Every aircraft model drawn in the scene skips Cesium's dynamic environment
+ * map (a sky render and GPU readback per model). The preload calls only warm
+ * the glTF cache and are never added to the scene, so they are left out:
+ * drawn models are the calls that set a minimum pixel size.
+ */
+const SOURCES = [
+  {
+    name: 'flights',
+    source: readLayerSource(new URL('./flights.js', import.meta.url)),
+  },
+  {
+    name: 'militaryFlights',
+    source: readLayerSource(new URL('./militaryFlights.js', import.meta.url)),
+  },
+  {
+    name: 'localAdsb',
+    source: readFileSync(
+      new URL('../layers/localAdsb/models.js', import.meta.url),
+      'utf8',
+    ),
+  },
+];
+
+test('the shared option turns the dynamic environment map off', () => {
+  assert.deepEqual({ ...AIRCRAFT_ENVIRONMENT_MAP_OPTIONS }, { enabled: false });
+  assert.ok(Object.isFrozen(AIRCRAFT_ENVIRONMENT_MAP_OPTIONS));
+});
+
+for (const { name, source } of SOURCES) {
+  test(`${name}: every drawn aircraft model skips the dynamic environment map`, () => {
+    const calls = [
+      ...source.matchAll(/(?:fromGltfAsync|loadModel)\(\{([\s\S]*?)\}\)/g),
+    ]
+      .map((match) => match[1])
+      .filter((options) => /\bminimumPixelSize:/.test(options));
+    assert.ok(calls.length >= 1, `expected drawn model calls in ${name}`);
+    for (const [index, options] of calls.entries())
+      assert.match(
+        options,
+        /\benvironmentMapOptions:\s*AIRCRAFT_ENVIRONMENT_MAP_OPTIONS\b/,
+        `${name} model call ${index + 1} must pass AIRCRAFT_ENVIRONMENT_MAP_OPTIONS`,
+      );
+  });
+}