fix(street-level): camera ownership, mesh refresh, panel CSP (Sameh's review)

- Photo framing and FOLLOW claim the camera through the application's
  navigation, injected with attachNavigation({ run, subscribeHandoff }):
  aircraft and satellite tracking is released first, the cockpit refuses,
  and FOLLOW stops when another feature takes the camera. No UI imports
  in the layer.
- The mesh sampler follows the mesh floor's rules: it waits for the
  visible tileset to finish streaming (visibleTilesetLoaded, now exposed
  by the mesh floor service), needs a real bare-earth prior and keeps to
  the shared meshFloorSampleWithinPrior window, which cameraFollow now
  uses too. A cell is probed again once the camera is half as far from
  it (down to 40 m), so a coarse early sample is replaced and redrawn.
- The MCP globe panel's CSP allows the Mapillary Graph API and its image
  CDN (https://*.xx.fbcdn.net).
- The tile proxy reads bodies with the shared readResponseBytesCapped.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/CURRENT-STATE.md

@@ -2959,7 +2959,10 @@ the mesh hides what is behind buildings and trees. A tile is drawn draped until
 its heights arrive; a geoid fallback leaves it draped. Within 900 m of the
 camera, `meshSampler.js` samples the rendered surface (`scene.sampleHeight`,
 ~11 m cells, nearest first, 6 ms idle budget) so lines also follow trenches,
-steep streets and roads under trees. Roads on elevated decks are still drawn at
+steep streets and roads under trees. It uses the mesh floor's rules (the
+visible tileset has finished streaming, a real bare-earth prior, the shared
+mesh window) and probes a cell again once the camera is half as far from it,
+down to 40 m, so coarse early samples are replaced as finer tiles load. Roads on elevated decks are still drawn at
 ground level. Framing a photo ignores mesh samples far below the bare earth
 (unloaded tiles).
 
@@ -2967,7 +2970,10 @@ The header pill is the layer switch. With one provider its chip is a layer
 switch too; with several, darkening the last lit chip turns the layer off. The
 viewer sits under the header with EXPAND, FIT/FILL, FOLLOW and close above the
 image. FOLLOW needs the Google 3D map stack (`attachMapStackController`) and
-stops when the stack changes. SINCE is a stepped slider whose readout names the
+stops when the stack changes. Framing a photo and turning FOLLOW on claim the
+camera through the application's navigation (`attachNavigation`), which
+releases aircraft and satellite tracking (and is refused in the cockpit);
+FOLLOW stops when another feature takes the camera. SINCE is a stepped slider whose readout names the
 cut-off date. The panel is portable (`street-level-panel` spec, minimum
 320 × 280, `dockOnCollapse`): a floating window gives spare height to the
 viewer, and collapsing it, double-clicking the header or SHRINK after EXPAND

scripts/package-boundaries.json

@@ -195,7 +195,9 @@
       "server/providers/common/same-site.js",
       "src/localRequestGate.mjs",
       "server/providers/common/rate-limit.js",
-      "src/sources/rateLimit.js"
+      "src/sources/rateLimit.js",
+      "server/providers/common/http.js",
+      "src/sources/httpBody.js"
     ],
     "external": ["pbf"]
   },

server/providers/mapillary/tiles.js

@@ -1,5 +1,6 @@
 import path from 'node:path';
 import { promises as fsp } from 'node:fs';
+import { readResponseBytesCapped } from '../common/http.js';
 import { stripTileLayers } from './trim.js';
 import {
   MAPILLARY_TILE_HOST,
@@ -350,35 +351,20 @@ async function fetchUpstream(address, signal) {
     }
     throw error;
   }
-  const declared = Number(response.headers.get('content-length'));
-  if (Number.isFinite(declared) && declared > TILE_MAX_BYTES) {
-    await response.body?.cancel().catch(() => {});
+  // Chunked or compressed bodies have no Content-Length: the cap applies as
+  // the body streams, and an oversized one also aborts the request.
+  try {
+    const bytes = await readResponseBytesCapped(
+      response,
+      TILE_MAX_BYTES,
+      signal,
+    );
+    return Buffer.from(bytes.buffer, bytes.byteOffset, bytes.byteLength);
+  } catch (error) {
+    if (error?.code !== 'RESPONSE_TOO_LARGE') throw error;
+    oversize.abort();
     throw new TileUpstreamError(502, 'Mapillary tile exceeds size cap');
   }
-  return readCapped(response, () => oversize.abort());
-}
-
-/**
- * Read a body, aborting once it passes TILE_MAX_BYTES: chunked or compressed
- * responses have no Content-Length to check first.
- */
-async function readCapped(response, abortRequest) {
-  if (!response.body) return Buffer.alloc(0);
-  const reader = response.body.getReader();
-  const chunks = [];
-  let total = 0;
-  for (;;) {
-    const { done, value } = await reader.read();
-    if (done) break;
-    total += value.byteLength;
-    if (total > TILE_MAX_BYTES) {
-      abortRequest();
-      await reader.cancel().catch(() => {});
-      throw new TileUpstreamError(502, 'Mapillary tile exceeds size cap');
-    }
-    chunks.push(value);
-  }
-  return Buffer.concat(chunks, total);
 }
 
 /** @type {{active: number, queue: Array<() => void>}} upstream slots */

src/app/layers/streetLevel.js

@@ -15,6 +15,7 @@ export function createApplicationStreetLevel({ surface, sources }) {
       input,
       render,
       ground: surface?.groundFloor ?? null,
+      meshFloor: surface?.meshFloor ?? null,
       terrain: surface?.terrain ?? null,
     },
   });

src/layers/streetLevel/cameraFollow.js

@@ -4,9 +4,6 @@ import { FOLLOW_EYE_HEIGHT_M } from './policy.js';
 /** Plausible ellipsoidal land heights: Dead Sea to Everest, with geoid slack. */
 const SURFACE_MIN_M = -500;
 const SURFACE_MAX_M = 9000;
-/** Rendered mesh window around the bare earth: roofs and bridges, not whole towers. */
-const MESH_BELOW_DEM_M = 15;
-const MESH_ABOVE_DEM_M = 80;
 
 /** Drive the globe camera from the street-level pose: continuously (follow) or once (framing). */
 export function createCameraFollow({ state, parts }) {
@@ -16,6 +13,48 @@ export function createCameraFollow({ state, parts }) {
     render?.governorRequestRender?.('street-level-follow');
   }
 
+  /**
+   * The application's camera authority (`attachNavigation`): `run(noun, move)`
+   * releases tracking and other owners before `move`, or refuses (cockpit);
+   * `subscribeHandoff` reports a newer owner. Without it, moves run directly.
+   */
+  let navigation = null;
+  let unsubscribeHandoff = null;
+  /** Set while our own claim stamps a handoff, so it does not end FOLLOW. */
+  let claiming = false;
+
+  /** Take the camera for `move`; false when the application refuses. */
+  function claim(move) {
+    if (!navigation?.run) {
+      move();
+      return true;
+    }
+    claiming = true;
+    try {
+      return (
+        navigation.run('photo', () => {
+          move();
+          return true;
+        }) === true
+      );
+    } finally {
+      claiming = false;
+    }
+  }
+
+  /** Another feature took the camera: stop following it. */
+  function onHandoff() {
+    if (claiming || !state.street.follow) return;
+    state.street.follow = false;
+    state.notify?.();
+  }
+
+  function attachNavigation(next) {
+    unsubscribeHandoff?.();
+    navigation = next || null;
+    unsubscribeHandoff = navigation?.subscribeHandoff?.(onHandoff) || null;
+  }
+
   /**
    * Ground under a photo. `sampleHeight` can return kilometres below the
    * ellipsoid before tiles load, so a sample counts only when plausible and
@@ -27,12 +66,13 @@ export function createCameraFollow({ state, parts }) {
     const caster = parts?.groundCaster;
     const dem = caster?.groundAt(lon, lat) ?? null;
     if (dem === null) caster?.prepare([[lon, lat]]);
+    // The application's mesh window around bare earth, once that is known.
+    const withinPrior = state.services.ground?.meshFloorSampleWithinPrior;
     const plausible = (height) =>
       Number.isFinite(height) &&
       height >= SURFACE_MIN_M &&
       height <= SURFACE_MAX_M &&
-      (dem === null ||
-        (height >= dem - MESH_BELOW_DEM_M && height <= dem + MESH_ABOVE_DEM_M));
+      (dem === null || !withinPrior || withinPrior(height, dem));
     let height = null;
     try {
       if (scene?.sampleHeightSupported) height = scene.sampleHeight(carto);
@@ -73,29 +113,31 @@ export function createCameraFollow({ state, parts }) {
     const { position, bearing, altitude } = state.street;
     if (!position || !state.viewer) return;
     const ground = groundHeightAt(position.lon, position.lat, altitude);
-    // Owned before the call: starting it cancels the previous flight (ours
-    // included) synchronously, and a zero-length one completes at once.
-    const flight = {};
-    framing = flight;
-    const release = () => {
-      if (framing === flight) framing = null;
-    };
-    state.viewer.camera.flyToBoundingSphere(
-      new Cesium.BoundingSphere(
-        Cesium.Cartesian3.fromDegrees(position.lon, position.lat, ground + 2),
-        4,
-      ),
-      {
-        offset: new Cesium.HeadingPitchRange(
-          Cesium.Math.toRadians(bearing || 0),
-          Cesium.Math.toRadians(-32),
-          140,
+    claim(() => {
+      // Owned before the call: starting it cancels the previous flight (ours
+      // included) synchronously, and a zero-length one completes at once.
+      const flight = {};
+      framing = flight;
+      const release = () => {
+        if (framing === flight) framing = null;
+      };
+      state.viewer.camera.flyToBoundingSphere(
+        new Cesium.BoundingSphere(
+          Cesium.Cartesian3.fromDegrees(position.lon, position.lat, ground + 2),
+          4,
         ),
-        duration: 1.6,
-        complete: release,
-        cancel: release,
-      },
-    );
+        {
+          offset: new Cesium.HeadingPitchRange(
+            Cesium.Math.toRadians(bearing || 0),
+            Cesium.Math.toRadians(-32),
+            140,
+          ),
+          duration: 1.6,
+          complete: release,
+          cancel: release,
+        },
+      );
+    });
   }
 
   /** Stop our framing flight if it is still in the air; another feature's flight is left alone. */
@@ -107,14 +149,32 @@ export function createCameraFollow({ state, parts }) {
   }
 
   function setFollow(enabled) {
-    state.street.follow = enabled === true && state.street.followAvailable;
-    // The framing tween would keep overwriting the follow view until it lands.
-    if (state.street.follow) {
-      cancelFraming();
-      followCamera();
+    const wanted = enabled === true && state.street.followAvailable;
+    if (wanted && !state.street.follow) {
+      // Following owns the camera until another feature takes it.
+      const granted = claim(() => {
+        state.street.follow = true;
+        // The framing tween would keep overwriting the follow view until it lands.
+        cancelFraming();
+        followCamera();
+      });
+      if (!granted) state.street.follow = false;
+    } else if (!wanted) {
+      state.street.follow = false;
     }
     state.notify?.();
   }
 
-  return { followCamera, lookAtPosition, cancelFraming, setFollow };
+  function destroy() {
+    attachNavigation(null);
+  }
+
+  return {
+    followCamera,
+    lookAtPosition,
+    cancelFraming,
+    setFollow,
+    attachNavigation,
+    destroy,
+  };
 }

src/layers/streetLevel/cameraFollow.test.mjs

@@ -156,3 +156,80 @@ test('turning FOLLOW on stops the framing flight so it cannot fight the follow v
   assert.equal(camera.cancelled, 1, 'the framing tween stops');
   assert.equal(views.length, 1, 'and the camera stands at the photo');
 });
+
+/**
+ * The application's camera authority: `run` releases tracking (here, a tracked
+ * entity) and stamps a handoff before the move, or refuses like the cockpit.
+ */
+function navigationFor(state, { refuse = false } = {}) {
+  const listeners = new Set();
+  const nav = {
+    runs: [],
+    run(noun, move) {
+      nav.runs.push(noun);
+      if (refuse) return false;
+      for (const listener of listeners)
+        listener({ generation: nav.runs.length });
+      state.viewer.trackedEntity = undefined;
+      return move(nav.runs.length);
+    },
+    subscribeHandoff(listener) {
+      listeners.add(listener);
+      return () => listeners.delete(listener);
+    },
+    handOff() {
+      for (const listener of listeners) listener({ generation: -1 });
+    },
+    listeners,
+  };
+  return nav;
+}
+
+test('framing a photo claims the camera through the application, releasing tracking', () => {
+  const { follow, state, flights } = setup({ sampled: 160 });
+  state.viewer.trackedEntity = { id: 'aircraft' };
+  const nav = navigationFor(state);
+  follow.attachNavigation(nav);
+  follow.lookAtPosition();
+  assert.deepEqual(nav.runs, ['photo']);
+  assert.equal(state.viewer.trackedEntity, undefined);
+  assert.equal(flights.length, 1);
+});
+
+test('a refused claim (cockpit) neither frames the photo nor turns FOLLOW on', () => {
+  const { follow, state, flights, views } = setup({ sampled: 160 });
+  follow.attachNavigation(navigationFor(state, { refuse: true }));
+  follow.lookAtPosition();
+  follow.setFollow(true);
+  assert.equal(flights.length, 0);
+  assert.equal(views.length, 0);
+  assert.equal(state.street.follow, false);
+});
+
+test('FOLLOW claims the camera once and ends when another feature takes it', () => {
+  const { follow, state, views } = setup({ sampled: 160 });
+  let notified = 0;
+  state.notify = () => notified++;
+  const nav = navigationFor(state);
+  follow.attachNavigation(nav);
+  follow.setFollow(true);
+  assert.equal(state.street.follow, true, 'our own handoff keeps FOLLOW on');
+  assert.deepEqual(nav.runs, ['photo']);
+  follow.followCamera();
+  assert.deepEqual(nav.runs, ['photo'], 'pose updates do not claim again');
+  assert.equal(views.length, 2);
+  nav.handOff();
+  assert.equal(state.street.follow, false);
+  assert.ok(notified >= 2);
+  follow.followCamera();
+  assert.equal(views.length, 2, 'the camera is no longer driven');
+});
+
+test('destroying the follow part stops listening for handoffs', () => {
+  const { follow, state } = setup({ sampled: 160 });
+  const nav = navigationFor(state);
+  follow.attachNavigation(nav);
+  assert.equal(nav.listeners.size, 1);
+  follow.destroy();
+  assert.equal(nav.listeners.size, 0);
+});

src/layers/streetLevel/index.js

@@ -40,8 +40,15 @@ export function createStreetLevelLayer({
   parts.groundCaster = services.terrain?.resolveEllipsoidalGround
     ? createGroundCaster({ terrain: services.terrain })
     : null;
+  // Mesh samples follow the application's rules: a real bare-earth prior,
+  // its mesh window, and a tileset that has finished streaming.
   parts.meshSampler = parts.groundCaster
-    ? createMeshSampler({ getViewer: () => state.viewer })
+    ? createMeshSampler({
+        getViewer: () => state.viewer,
+        groundAt: parts.groundCaster.groundAt,
+        withinPrior: services.ground?.meshFloorSampleWithinPrior ?? null,
+        tilesReady: services.meshFloor?.visibleTilesetLoaded ?? null,
+      })
     : null;
   parts.credits = createCredits();
   parts.marker = createMarker(context);
@@ -375,6 +382,7 @@ export function createStreetLevelLayer({
         entry.instance.destroy(viewer);
       parts.marker.destroy(viewer);
       parts.meshSampler?.destroy();
+      parts.follow.destroy();
       unsubscribeMapStack?.();
       unsubscribeMapStack = null;
       mapStack = null;
@@ -405,6 +413,15 @@ export function createStreetLevelLayer({
       };
     },
 
+    /**
+     * The application's camera authority: `run(noun, move)` and
+     * `subscribeHandoff(listener)`. Framing and FOLLOW claim the camera
+     * through it, and FOLLOW stops when another feature takes the camera.
+     */
+    attachNavigation(navigation) {
+      parts.follow.attachNavigation(navigation);
+    },
+
     /** The application map stack; FOLLOW is available only on Google 3D. */
     attachMapStackController(controller) {
       unsubscribeMapStack?.();

src/layers/streetLevel/meshSampler.js

@@ -5,8 +5,10 @@ import { metresBetween, whenIdle } from './view.js';
  * Google 3D surface heights for ground casting (groundCast.js refineHeights):
  * one cached `scene.sampleHeight` probe per ~11 m cell. Each probe renders a
  * pick pass (1–3 ms), so probes run in budgeted idle slices, nearest the
- * camera first and only within MESH_SAMPLE_RADIUS_M. A miss (tiles not
- * streamed yet) is retried later. Probes hit 3D tilesets only.
+ * camera first and only within MESH_SAMPLE_RADIUS_M. Like the application's
+ * mesh floor, a probe waits for the visible tileset to finish streaming and a
+ * sample counts only within the shared window around a real bare-earth height;
+ * anything else is a miss, retried later. Probes hit 3D tilesets only.
  */
 
 /** Cell size, in degrees (~11 m): samples are shared within a cell. */
@@ -19,6 +21,16 @@ export const MESH_SAMPLE_BUDGET_MS = 6;
 export const MESH_RERANK_M = 100;
 /** A cell whose probe missed is tried again after this long. */
 export const MESH_MISS_RETRY_MS = 8000;
+/** While the visible tileset is streaming, the next probe waits this long. */
+export const MESH_STREAMING_WAIT_MS = 500;
+/**
+ * A sampled cell is probed again once the camera is half as far from it as at
+ * its last probe (finer tiles have loaded by then), down to this distance:
+ * at most a handful of probes per cell.
+ */
+export const MESH_REFRESH_MIN_M = 40;
+/** A refreshed sample that moved less than this is not redrawn. */
+const MESH_REFRESH_CHANGE_M = 0.5;
 /** Cached cells (and remembered misses) before they are dropped and refilled. */
 const MESH_CACHE_MAX = 80_000;
 /** Listeners hear about new samples at most this often. */
@@ -80,10 +92,16 @@ function overlays(scene) {
 }
 
 /**
- * @param {{getViewer: () => object|null, budgetMs?: number, radiusM?: number, cacheMax?: number, now?: () => number}} options
+ * `groundAt(lon, lat)` is the bare-earth height or null, `withinPrior(height,
+ * prior)` the application's mesh window, and `tilesReady(scene)` whether the
+ * visible tileset has finished streaming.
+ * @param {{getViewer: () => object|null, groundAt?: Function, withinPrior?: Function, tilesReady?: Function, budgetMs?: number, radiusM?: number, cacheMax?: number, now?: () => number}} options
  */
 export function createMeshSampler({
   getViewer,
+  groundAt = null,
+  withinPrior = null,
+  tilesReady = null,
   budgetMs = MESH_SAMPLE_BUDGET_MS,
   radiusM = MESH_SAMPLE_RADIUS_M,
   cacheMax = MESH_CACHE_MAX,
@@ -91,6 +109,8 @@ export function createMeshSampler({
 }) {
   /** cell key → sampled mesh height (ellipsoidal metres). */
   const heights = new Map();
+  /** cell key → camera distance (m) at the cell's last probe. */
+  const probedFrom = new Map();
   /** cell key → retry time for probes that hit nothing; bounded like the height cache. */
   const misses = new Map();
   /** cell key → queued cell, so a cell is queued once. */
@@ -114,16 +134,40 @@ export function createMeshSampler({
     return heights.get(meshCellKey(lon, lat));
   }
 
-  /** The point under the camera, or null. */
+  /** The point under the camera, with the camera's height, or null. */
   function cameraCentre() {
     const carto = getViewer()?.camera?.positionCartographic;
     if (!carto) return null;
     return {
       lon: Cesium.Math.toDegrees(carto.longitude),
       lat: Cesium.Math.toDegrees(carto.latitude),
+      height: carto.height,
     };
   }
 
+  /** Camera distance (m) to a cell at `height`, from its ground distance. */
+  function cameraDistance(ground, centre, height) {
+    const above = (centre.height ?? 0) - (height ?? 0);
+    return Number.isFinite(above)
+      ? Math.hypot(ground, Math.max(0, above))
+      : ground;
+  }
+
+  /** A sampled cell is probed again once the camera is half as far as before. */
+  function dueForRefresh(key, distance) {
+    const last = probedFrom.get(key);
+    return last > MESH_REFRESH_MIN_M && distance < last / 2;
+  }
+
+  /** A probe result the application would accept, or undefined. */
+  function validated(height, lon, lat) {
+    if (!Number.isFinite(height)) return undefined;
+    if (!groundAt) return height;
+    const prior = groundAt(lon, lat);
+    if (!Number.isFinite(prior)) return undefined;
+    return !withinPrior || withinPrior(height, prior) ? height : undefined;
+  }
+
   /**
    * Ask for the cells under [lon, lat] points; the list is read later, so do
    * not mutate it. Out-of-range cells are dropped; callers ask again on move.
@@ -147,14 +191,20 @@ export function createMeshSampler({
         const [lon, lat] = points[pending.next++];
         if (!Number.isFinite(lon) || !Number.isFinite(lat)) continue;
         const key = meshCellKey(lon, lat);
-        if (heights.has(key) || wanted.has(key)) continue;
+        if (wanted.has(key)) continue;
         const cell = {
           key,
           lon: cellOf(lon) * MESH_CELL_DEG,
           lat: cellOf(lat) * MESH_CELL_DEG,
           distance: 0,
         };
-        if (metresBetween(cell, centre) > radiusM) continue;
+        const ground = metresBetween(cell, centre);
+        if (ground > radiusM) continue;
+        if (
+          heights.has(key) &&
+          !dueForRefresh(key, cameraDistance(ground, centre, heights.get(key)))
+        )
+          continue;
         const retryAt = misses.get(key);
         if (retryAt !== undefined) {
           if (retryAt > time) continue;
@@ -220,6 +270,15 @@ export function createMeshSampler({
     const scene = getViewer()?.scene;
     const centre = cameraCentre();
     if (!enabled || !scene?.sampleHeightSupported || !centre) return;
+    // Mid-stream tiles answer with coarse heights: wait for the stream.
+    if (tilesReady && !tilesReady(scene)) {
+      running = true;
+      setTimeout(() => {
+        running = false;
+        schedule();
+      }, MESH_STREAMING_WAIT_MS);
+      return;
+    }
     // Nearest first, ranked from where the camera was; out-of-range cells
     // are dropped (they stay bare earth).
     let worked = false;
@@ -241,7 +300,8 @@ export function createMeshSampler({
       const { key, lon, lat } = heapPop(queue);
       wanted.delete(key);
       // Ranked from up to MESH_RERANK_M away: check the range from here.
-      if (metresBetween({ lon, lat }, centre) > radiusM) continue;
+      const ground = metresBetween({ lon, lat }, centre);
+      if (ground > radiusM) continue;
       probed++;
       const probeStarted = now();
       let height;
@@ -254,15 +314,27 @@ export function createMeshSampler({
         height = undefined;
       }
       probeMs = probeMs * 0.75 + (now() - probeStarted) * 0.25;
-      if (!Number.isFinite(height)) {
-        if (misses.size >= cacheMax) misses.clear();
-        misses.set(key, Date.now() + MESH_MISS_RETRY_MS);
+      height = validated(height, lon, lat);
+      const previous = heights.get(key);
+      if (height === undefined) {
+        // A failed refresh keeps the old sample, and waits for a closer camera.
+        if (previous !== undefined)
+          probedFrom.set(key, cameraDistance(ground, centre, previous));
+        else {
+          if (misses.size >= cacheMax) misses.clear();
+          misses.set(key, Date.now() + MESH_MISS_RETRY_MS);
+        }
         continue;
       }
-      if (heights.size >= cacheMax) forget();
+      if (previous === undefined && heights.size >= cacheMax) forget();
       misses.delete(key);
       heights.set(key, height);
-      fresh.push([lon, lat]);
+      probedFrom.set(key, cameraDistance(ground, centre, height));
+      if (
+        previous === undefined ||
+        Math.abs(height - previous) >= MESH_REFRESH_CHANGE_M
+      )
+        fresh.push([lon, lat]);
     }
     if (fresh.length && !notifyTimer)
       notifyTimer = setTimeout(emit, MESH_NOTIFY_MS);
@@ -271,6 +343,7 @@ export function createMeshSampler({
 
   function forget() {
     heights.clear();
+    probedFrom.clear();
     misses.clear();
   }
 

src/layers/streetLevel/meshSampler.test.mjs

@@ -4,9 +4,12 @@ import * as Cesium from 'cesium';
 import {
   MESH_CELL_DEG,
   MESH_MISS_RETRY_MS,
+  MESH_REFRESH_MIN_M,
   MESH_SAMPLE_BUDGET_MS,
+  MESH_STREAMING_WAIT_MS,
   createMeshSampler,
 } from './meshSampler.js';
+import { meshFloorSampleWithinPrior } from '../../data/groundFloor.js';
 import { metresBetween } from './view.js';
 
 const settle = (ms = 60) => new Promise((resolve) => setTimeout(resolve, ms));
@@ -267,3 +270,107 @@ test('the sampling range is measured the short way round the date line', (t) =>
   assert.ok(Math.abs(Math.abs(probes[0].lon) - 179.9999) < MESH_CELL_DEG);
   sampler.destroy();
 });
+
+/** A scene whose mesh height can change (finer tiles) and a camera that can move. */
+function liveViewer({ surface = 80, height = 700, ready = () => true } = {}) {
+  const tileset = Object.create(Cesium.Cesium3DTileset.prototype);
+  const probes = [];
+  const viewer = {
+    surface,
+    ready,
+    scene: {
+      sampleHeightSupported: true,
+      primitives: { length: 1, get: () => tileset },
+      sampleHeight(carto) {
+        probes.push(carto);
+        return viewer.surface;
+      },
+    },
+    camera: {
+      positionCartographic: { longitude: 10 * RAD, latitude: 50 * RAD, height },
+    },
+  };
+  return { viewer, probes };
+}
+
+function liveSampler(viewer, options = {}) {
+  return createMeshSampler({
+    getViewer: () => viewer,
+    groundAt: () => 75,
+    withinPrior: meshFloorSampleWithinPrior,
+    tilesReady: () => viewer.ready(),
+    ...options,
+  });
+}
+
+test('a sample is probed again once the camera is twice as close, and the change is redrawn', async () => {
+  const { viewer, probes } = liveViewer({ surface: 80, height: 700 });
+  const sampler = liveSampler(viewer);
+  sampler.setEnabled(true);
+  const heard = [];
+  sampler.onSampled((batch) => heard.push(batch.length));
+  sampler.request([[10.001, 50]]);
+  await settle(900);
+  assert.equal(sampler.meshAt(10.001, 50), 80);
+  // Finer tiles load: the surface is really 100 m.
+  viewer.surface = 100;
+  sampler.request([[10.001, 50]]);
+  await settle();
+  assert.equal(probes.length, 1, 'no new probe from the same distance');
+  assert.equal(sampler.meshAt(10.001, 50), 80);
+  viewer.camera.positionCartographic.height = 250;
+  sampler.request([[10.001, 50]]);
+  await settle(900);
+  assert.equal(probes.length, 2);
+  assert.equal(sampler.meshAt(10.001, 50), 100);
+  assert.deepEqual(heard, [1, 1], 'the new height is announced for a redraw');
+  sampler.destroy();
+});
+
+test('refreshing stops once a cell was probed from close by', async () => {
+  const { viewer, probes } = liveViewer({ surface: 80, height: 110 });
+  viewer.camera.positionCartographic.longitude = 10.001 * RAD;
+  const sampler = liveSampler(viewer);
+  sampler.setEnabled(true);
+  sampler.request([[10.001, 50]]);
+  await settle();
+  viewer.camera.positionCartographic.height = 85;
+  sampler.request([[10.001, 50]]);
+  await settle();
+  assert.equal(probes.length, 1, `probed from under ${MESH_REFRESH_MIN_M} m`);
+  sampler.destroy();
+});
+
+test('probes wait while the visible tileset is still streaming', async () => {
+  let ready = false;
+  const { viewer, probes } = liveViewer({ ready: () => ready });
+  const sampler = liveSampler(viewer);
+  sampler.setEnabled(true);
+  sampler.request([[10.001, 50]]);
+  await settle(MESH_STREAMING_WAIT_MS * 2);
+  assert.equal(probes.length, 0);
+  ready = true;
+  await settle(MESH_STREAMING_WAIT_MS * 2);
+  assert.equal(probes.length, 1);
+  assert.equal(sampler.meshAt(10.001, 50), 80);
+  sampler.destroy();
+});
+
+test('a sample needs a real bare-earth prior and must sit in the shared mesh window', async () => {
+  const { viewer } = liveViewer({ surface: 300 });
+  const unknown = liveSampler(viewer, { groundAt: () => null });
+  unknown.setEnabled(true);
+  unknown.request([[10.001, 50]]);
+  const outside = liveSampler(viewer);
+  outside.setEnabled(true);
+  outside.request([[10.001, 50]]);
+  await settle();
+  assert.equal(unknown.meshAt(10.001, 50), undefined, 'no prior: not kept');
+  assert.equal(
+    outside.meshAt(10.001, 50),
+    undefined,
+    '225 m above it: not kept',
+  );
+  unknown.destroy();
+  outside.destroy();
+});

src/services/meshFloorSampler.js

@@ -195,5 +195,9 @@ export function createMeshFloorSampler({
     () => eventTarget?.removeEventListener('gev:map-stack-changed', onStack),
     { once: true },
   );
-  return { sampleMeshFloorCells, cachedGroundFloor };
+  return {
+    sampleMeshFloorCells,
+    cachedGroundFloor,
+    visibleTilesetLoaded: _visibleTilesetLoaded,
+  };
 }

src/tools/globePanel.js

@@ -14,8 +14,9 @@ export const PANEL_WORKER_PRELUDE_PATH = 'cesium/worker-prelude.js';
 
 /**
  * Sites the app's browser code loads from directly: map imagery, 3D tiles,
- * terrain and fonts. Everything from the app's own server comes through the
- * MCP server.
+ * terrain, fonts, and Street Level's Mapillary Graph API and image CDN (its
+ * coverage tiles come through the app's server). Everything from the app's
+ * own server comes through the MCP server.
  */
 const PROVIDER_ORIGINS = Object.freeze([
   'https://tile.googleapis.com',
@@ -35,6 +36,9 @@ const PROVIDER_ORIGINS = Object.freeze([
   'https://gibs.earthdata.nasa.gov',
   'https://fonts.googleapis.com',
   'https://fonts.gstatic.com',
+  'https://graph.mapillary.com',
+  // Mapillary photos come from regional hosts, e.g. scontent-man2-1.xx.fbcdn.net.
+  'https://*.xx.fbcdn.net',
 ]);
 
 export const MCP_APP_MIME_TYPE = 'text/html;profile=mcp-app';

src/tools/globePanel.test.mjs

@@ -7,6 +7,21 @@ import {
 } from './globePanel.js';
 import { panelRuntime } from '../app/globePanelRuntime.js';
 import { composeCatalog, coreTools } from './index.js';
+import { MAPILLARY_GRAPH_HOST } from '../layers/streetLevel/providers/mapillary/policy.js';
+
+/** Whether a CSP source list allows a URL (exact origin or `https://*.host`). */
+function allows(sources, url) {
+  const { origin, protocol, hostname } = new URL(url);
+  return sources.some((source) => {
+    if (source === origin) return true;
+    const wildcard = source.match(/^(https:)\/\/\*\.(.+)$/);
+    return (
+      Boolean(wildcard) &&
+      protocol === wildcard[1] &&
+      hostname.endsWith(`.${wildcard[2]}`)
+    );
+  });
+}
 
 test('the globe panel is an MCP Apps resource that loads the app through its server', () => {
   const resource = createGlobePanelResource({
@@ -45,6 +60,27 @@ test('the globe panel is an MCP Apps resource that loads the app through its ser
   assert.doesNotThrow(() => new Function(script));
 });
 
+test('the panel lets Street Level reach Mapillary from inside the embed', () => {
+  const { csp } = createGlobePanelResource({
+    runtime: panelRuntime,
+    panelKey: 'test-key',
+  })._meta.ui;
+  // Graph API lookups (nearest image, sequences) and MapillaryJS photo loads.
+  for (const url of [
+    `${MAPILLARY_GRAPH_HOST}/images?fields=id&bbox=1,2,3,4`,
+    'https://scontent-man2-1.xx.fbcdn.net/m1/v/t6/photo.jpg',
+    'https://scontent-iad3-2.xx.fbcdn.net/m1/v/t6/photo.jpg',
+  ]) {
+    assert.ok(allows(csp.connectDomains, url), `connect-src allows ${url}`);
+    assert.ok(allows(csp.resourceDomains, url), `img-src allows ${url}`);
+  }
+  assert.equal(allows(csp.connectDomains, 'https://evil.example/x'), false);
+  assert.equal(
+    allows(csp.connectDomains, 'https://fbcdn.net.evil.example/'),
+    false,
+  );
+});
+
 test('the globe panel needs a request key', () => {
   for (const panelKey of [undefined, '', 42])
     assert.throws(

src/ui/applicationShell.js

@@ -939,6 +939,12 @@ export class StyleManager extends ShellFacade {
     this._streetLevelControls?.destroy();
     this._streetLevelControls = null;
     if (!this._streetLevelPanel || !streetLevelLayer) return;
+    // Photo framing and FOLLOW release tracking like any explicit flight.
+    streetLevelLayer.attachNavigation?.({
+      run: (noun, move) => this._runExplicitNavigation(noun, move),
+      subscribeHandoff: (listener) =>
+        this._navigation.subscribeCameraHandoff(listener),
+    });
     this._streetLevelControls = new StreetLevelControls({
       root: this._streetLevelPanel,
       layer: streetLevelLayer,
@@ -1577,6 +1583,7 @@ export class StyleManager extends ShellFacade {
     this._cameraOrientationControls?.destroy();
     this._clearLayersControl?.destroy();
     this._cctvControls?.destroy();
+    this.services?.streetLevelLayer?.attachNavigation?.(null);
     this._streetLevelControls?.destroy();
     this._radioControls?.destroy();
     this._localSdrControls?.destroy();