docs(performance): cables rewrite in #1722 and clouds shader in #1721

Co-Authored-By: Claude Fable 5.2 <[email protected]>

changelog.d/1707-cables-staged-landing-markers.md

@@ -1,3 +0,0 @@
-- Shorten the freeze when Submarine cables is switched on from about 1.4 s to
-  about 0.2 s. Landing markers are now shown a few dozen per frame instead of
-  all at once (mazy1998, #1707).

changelog.d/1722-cables-batched-primitives.md

@@ -1,4 +0,0 @@
-- Submarine cables draw from a few batched primitives instead of thousands of
-  entities. Switching the layer off and back on, and zooming with it on, no
-  longer stall the page, and it holds about 900 MB less memory. Double-click
-  no longer starts Cesium's entity tracking on a cable (mazy1998, #1722).

docs/CURRENT-STATE.md

@@ -1541,14 +1541,12 @@ query. Movement within an accepted or pending query reuses it. Markers retain
 their Cesium identity while their geometry is unchanged; refreshes preserve
 selection without replaying a click event.
 
-Data Centers and Dams release their built Cesium data sources
+Data Centers, Dams and Submarine Cables release their built Cesium data sources
 and record references when disabled. Parsed datasets remain cached for the layer
 lifetime, so re-enable rebuilds entities without downloading or parsing again;
 this can take longer than simply revealing hidden entities. Destruction clears
 the parsed cache as well. A disable during loading cannot leave a completed
-build hidden in the scene. Submarine Cables draws with its own primitives
-instead of entities and only hides them when disabled (see "Bundled geography
-and submarine cable components").
+build hidden in the scene.
 
 CCTV exposes a factory through `./layers/cctv`. Catalog and health requests,
 frame/media URLs, camera records, ground placement, geometry queues, playback,
@@ -8149,37 +8147,17 @@ an error. Without feeds it keeps the WebUSB statuses. See
 Submarine cables use separate source, geometry, rendering, interaction and
 lifecycle modules. The layer factory accepts cable and landing-point GeoJSON
 collections from a source with `fetch(signal)` and a display label. The default
-source loads the same bundled TeleGeography files. Load ownership prevents
-cancelled work from adding anything to the scene after teardown: the fetch is
-the load's only await, and everything is built in the turn after it.
+source loads the same bundled TeleGeography files. Disabling still removes all
+three Cesium data sources; enabling rebuilds from the accepted parsed cache,
+and destroying clears it. Load ownership prevents cancelled work from adding
+entities after teardown.
 
-The layer draws with four Cesium primitives of its own and creates no entity
-or data source. Every line is one instance of a single
-`GroundPolylinePrimitive` (per-line colour and show flag, rhumb lines,
-tessellated in a worker; a map-stack change re-classifies it in place). Every
-point is a billboard in one `BillboardCollection`. Reference tips are one
-`PointPrimitiveCollection`, and the stems of the references in view are one
-static polyline `Primitive`: a horizon sweep that moved a tip or changed which
-references are in view builds a replacement in a worker, and it replaces the
-shown stems once it is ready. Disabling hides the lines, markers and tips and
-keeps them, so enabling again neither fetches nor builds them (only the stems
-are redrawn, for the new view); destroying removes everything. These are
-the same primitives Cesium built from the layer's entities, so the layer looks
-the same. Polygon geometry in a custom source is not drawn, and GeoJSON
-simplestyle properties (`marker-color`, `stroke` and the like) are not read.
-
-Every line and marker from multipart cable or landing-point geometry stays tied
-to its source feature. Each part gets its own feature's styling, click
+Every Cesium entity from multipart cable or landing-point geometry stays tied
+to its source feature, including generated IDs and IDs that collide with
+Cesium's multipart suffixes. Each segment gets its own feature's styling, click
 destination and horizon-culling reference, and each source feature has one
 reference stem. The source collections are not modified.
 
-Landing markers are ground-clamped billboards. A marker starts hidden and
-unclamped; the horizon sweep clamps and shows the visible ones 48 per rendered
-frame (`CABLE_LANDING_REVEALS_PER_FRAME`), so the terrain height reads are
-never one task. A marker is clamped once: Cesium then keeps it on the surface
-as terrain loads, and hiding or showing it again reads nothing; hiding is
-immediate.
-
 Natural Earth regions and neighborhood polygon lookup are package exports.
 Their existing lazy loaders, retry behavior, bundled datasets and attribution
 are unchanged. The cable dataset remains CC BY-NC-SA 3.0 and is not covered by

docs/PERFORMANCE-AUDIT-2026-11.md

@@ -0,0 +1,322 @@
+# Slowdown audit, November 2026
+
+A sweep of `main` (`c02ede3bb`, 13 November 2026) for bugs that freeze the page
+or hold the frame rate down. This page lists what was found, why it happens and
+how to fix it, and names the pull request that carries each fix.
+
+[PERFORMANCE.md](PERFORMANCE.md) is the measured baseline of a healthy build;
+this page is the list of things that fall outside it.
+
+## How it was measured
+
+- Keyless dev server, headless Chrome at 1440 x 900 on Apple silicon (Metal
+  through ANGLE), default globe map.
+- Per scenario: load, a spell at rest, scripted drags and wheel zooms, then a
+  settle. Long tasks were counted with a `PerformanceObserver`, the hot function
+  named from a CPU profile, and `globe.getHeight`, `scene.sampleHeight`,
+  `scene.pick` and friends wrapped to count calls and time.
+- A long task is one main-thread task over 50 ms. With no layers on, the
+  baseline is two at load (longest about 240 ms) and none afterwards, with zero
+  frames rendered while the camera is still.
+- Four profiling sessions ran on one machine at the same time, so absolute
+  timings carry some noise. Ratios against the baseline are what to read.
+
+Nothing here was measured on Google Photorealistic 3D Tiles, on a discrete or
+integrated PC GPU, or with keyed feeds (AISStream, FIRMS, TomTom). Those rows
+are marked "read in code".
+
+## Findings and fixes
+
+Worst first. "Fix" names the pull request that carries the fix.
+
+### Measured
+
+| # | Where | What happens | Fix |
+| ---: | --- | --- | --- |
+| 1 | Bike Share, local data layers, Transit, Rail | 18 s freeze switching Bike Share on over New York (2,519 stations); 2.7 s on Data Centers; multi-second freezes with Transit while zooming | #1688, #1689 |
+| 2 | Shipwrecks | 3 to 5 s freeze when the markers are built over loaded terrain; a share link with the layer on held the loading screen for 22.9 s in one run | #1703 |
+| 3 | Camera | Rendering stops until reload: at a whole-globe view looking straight down, pan a few times, then scroll one notch | #1704 |
+| 4 | Street Traffic | Zooming at 250 m over Manhattan: 25 long tasks in 24 s, longest 746 ms, 6.6 s in total | #1705 |
+| 5 | ALPR cameras | Depth samples inside the overlay paint, repeated on every re-enable: 240 samples and about 1 s across eight toggles. A first-sample freeze of up to 1.9 s was seen in the sweep but not on a second day | #1706 |
+| 6 | Wind | First zoom after load: up to 14 long tasks (longest 414 ms). Re-measured as one-off shader links, not a standing cost: see below | none proposed |
+| 7 | Submarine cables | About 2 s of long tasks on load, heap briefly at 1 GB, about 0.5 s again on each re-enable | #1707 (first step), #1722 (batched primitives) |
+| 8 | Live Flights at whole-globe view with detection labels | Fine on the test machine; at 4x CPU throttle, 8 fps with 143 long tasks in 15 s | #1708 (fleet pass), #1719 (overlay) |
+| 9 | Radio | 7 to 10 long tasks when the directory loads, longest 447 ms | #1709 |
+| 10 | Pointer pick | Not reproduced on a second look: see below | none needed |
+| 11 | CCTV | A still-image camera holds continuous rendering at 60 frames a second although its picture changes about every 10 s | #1710 |
+
+### Read in code
+
+| # | Where | What happens | Fix |
+| ---: | --- | --- | --- |
+| 12 | `/api/firms` | The whole fire set is filtered, serialised and sent uncompressed on every request; 15 to 55 MB estimated in a heavy season | #1711 |
+| 13 | AIS store | Both vessel maps are walked on every position message, and sorted whole once past the cap | #1712 |
+| 14 | Satellite clouds on the 3D Tiles map | A CPU pass over a 4096 x 2048 image, 90 to 180 ms measured on a synthetic canvas, twice in a row | #1713 (canvas path), #1721 (shader) |
+| 15 | NVG and FLIR styles | Over 100 texture reads per pixel, and 60 renders a second while the style is on. Measured afterwards: the reads cost 0.4 ms a frame at 1440 x 900 and 1.2 ms at 2560 x 1440 | #1718 |
+| 16 | Wind server | Full 0.25 degree GRIB fields decoded on the event loop. Measured afterwards: 68 ms blocked per warm refresh, about 250 ms on the first, about 400 ms when all six keys refresh together | #1717 |
+| 17 | Imported geo files and other per-feature ground clamps | Measured afterwards: imported files do not freeze; see below | none needed |
+
+## Cause and fix, per finding
+
+### 1. Terrain height reads
+
+`globe.getHeight` casts a ray against the mesh of the tile under the point, and
+`scene.sampleHeight` renders a depth pass. Transit asked for every trail fix of
+every vehicle several times per poll; Bike Share sampled every station in one
+go. The fix keeps heights per point in one shared reader with a read budget
+(`src/services/terrainSurface.js`) and spreads the depth samples across frames.
+
+### 2. Shipwrecks
+
+`rebuild()` in `src/layers/shipwrecks/index.js` adds 7,958 billboards with
+`heightReference: CLAMP_TO_GROUND`. Each constructor runs
+`Billboard._updateClamping`, which intersects a ray with the terrain mesh,
+synchronously: 4.8 of the 4.9 s. The cost is only paid when terrain is loaded
+at the time the markers are built, so a cold start with the layer in the URL
+sometimes escapes it.
+
+Fix: do not clamp. Wrecks are at sea and the markers already ignore the depth
+test, so place them on the ellipsoid with `HeightReference.NONE`.
+
+### 3. Camera: rendering stops after pan then zoom
+
+Pure Cesium; no application code is involved. Above 1,000 km,
+`ScreenSpaceCameraController` `handleZoom` rotates the camera about the cross
+product of the picked point's normal and the screen centre's normal whenever
+their dot product is between 0 and 1. With the pointer on the exact centre pixel
+the two are the same vector, yet `n · n` often rounds to `0.9999999999999999`,
+so the check passes with a zero axis. `Camera.rotate` then throws
+`DeveloperError: normalized result is not a number` from
+`Scene.initializeFrame`, outside the scene's own try/catch, so
+`scene.renderError` never fires and Cesium stops its render loop for good. The
+pans in the first reproduction only moved the camera to a pose where the
+rounding goes that way.
+
+Fix: make `camera.rotate` ignore a zero or non-finite axis, and recover from any
+stopped loop by restoring the last drawn camera pose and restarting it a bounded
+number of times before showing Cesium's error panel.
+
+### 4. Street Traffic road loading
+
+Three costs in one task after the detail tiles arrive, in
+`src/layers/traffic/source.js`:
+
+- `outsideDetailTiles` clips every coarse z12 road against every loaded detail
+  tile (up to 16) for four regions.
+- The composed set is then handed on with `replace: true`, so
+  `ingestion.js` parses every road again although each tile was parsed as it
+  streamed.
+- `parseRoads` (`model.js`) asks `cachedGroundFloor` once per coordinate, and
+  each call builds several string keys.
+
+Fix: clip once per coarse tile against the detail tiles' union box and slice the
+work across frames (or do it in the vector-tile worker); reuse the roads parsed
+while streaming and parse only the clipped coarse remainder; look the floor up
+once per floor cell within a parse.
+
+This is separate from the one-viewport-tile-at-a-time loading recorded in
+[KNOWN-ISSUES.md](KNOWN-ISSUES.md).
+
+### 5. ALPR cameras
+
+`refineAnchors` and `anchorFor` in `src/layers/alpr/overlay.js` call
+`scene.sampleHeight` from the overlay's paint, four per paint. Each is a depth
+render and a `readPixels`; the first one also compiles the pick shader. Results
+are kept on the entity, so a rebuild or a re-enable samples everything again.
+
+Fix: on a terrain globe read `globe.getHeight` through the shared terrain reader
+instead of sampling; keep the answers in a map keyed by camera that outlives the
+entities; move what sampling remains out of the paint into a queue of one per
+frame.
+
+### 6. Wind
+
+The first reading blamed the layer's 916,476 vertices for slow depth reads
+during zoom. Measuring again did not support that: depth reads cost the same
+with and without Wind, hiding every wind primitive left pick time unchanged, and
+the stalls appear on the first zoom only, as shader programs link (seven
+programs, about 0.5 s, long tasks up to 166 ms). Later zooms had none.
+
+The roughly 30 renders a second are the animation itself. It is already capped
+at 30 Hz and stops when paused, hidden, out of view or under reduced motion;
+lowering the rate would change how the layer looks. `disable()` releases the
+baked geometry on purpose, at the price of one task of about 130 ms on
+re-enable.
+
+A third look, timing every program link on a preview build, settled it: Wind
+owns two shader programs, both link during load in 9 to 18 ms, and none ever
+linked during a zoom. The programs that do link on a zoom are Cesium's own
+globe-surface variants, with Wind on or off, and Cesium links them
+synchronously. No fix is proposed.
+
+### 7. Submarine cables
+
+`src/layers/submarineCables/ingestion.js` loads both collections through
+`Cesium.GeoJsonDataSource` with `clampToGround`. Switching the layer on is one
+task of about 1.4 s, and 1.2 s of it is Cesium reading the terrain height for
+the 1,917 ground-clamped landing markers, all created in the first frame,
+including the ones behind the globe.
+
+Fix, first step: start the landing markers hidden and let the existing horizon
+sweep show the visible ones a few dozen per frame.
+
+Fix, second step: draw from batched primitives in place of the entity data
+sources: one ground polyline primitive for the lines, one billboard collection
+for the landing markers, one point collection and one static polyline primitive
+for the reference stems, all kept while the layer is off. That removes the
+visualiser tasks, the stall on switch-off and on re-enable, and about 900 MB of
+heap. The first switch-on still links shaders and builds the ground-line
+geometry once.
+
+### 8. Live Flights at whole-globe view
+
+Two costs that scale with the 7,500 aircraft of a full poll:
+
+- The fleet pass (`src/layers/flights/rendering.js`, every 80 ms) dead-reckons
+  each visible aircraft and asks `cachedGroundFloor` for it, including aircraft
+  at cruise altitude that can never touch the floor. Each lookup formats numbers
+  to strings several times and rewrites a cache entry: 40% of the busy time.
+- The detection overlay (`src/data/detection.js` `_drawOverlay`) collects every
+  detectable object and strokes every bracket on every frame.
+
+Fix for the first: skip the floor path for a contact clearly above any terrain,
+make the floor-cell key a number, and stop promoting the cache entry on every
+read.
+
+The second turned out smaller than it looked. The bracket strokes are already
+one path per colour, and collecting the objects is about 3 ms of a 56 ms frame
+at 4x throttle once the first fix is in. What costs is the per-object loop in
+`_drawOverlay` (projection, occlusion, alpha, twelve path calls per bracket).
+
+Fix for the second: keep what a sweep built and reuse it on the next paint when
+the view and every contact are exactly what it was built from, compared value
+by value so no layer has to announce a change. Between two fleet passes most
+paints qualify, which cuts frame work by a fifth to a third on a still camera
+at full speed. At 4x throttle a frame outlasts a fleet pass, no paint
+qualifies, and the gain is a few milliseconds; the fleet pass is what
+dominates there.
+
+### 9. Radio
+
+`stationTags()` in `src/layers/radio/categories.js` splits and normalises a
+station's tags on every `hasTag` call, and `buildRadioCategories` runs that for
+every station against every category, twice.
+
+Fix: normalise once per station at ingest and count categories from that.
+
+### 10. Pointer pick
+
+Three sessions saw a single `scene.pick` of 207 to 342 ms during a gesture and
+attributed it to `pickPointer` in `src/voice/pointerPick.js`. Timing every pick
+across pointer rests, drags and wheel bursts did not bear that out: of 78 picks
+with CCTV on over London all but two took 3 to 8 ms, and with five heavy layers
+on, 81 picks took 5 to 30 ms apart from the first (135 ms). `pickPointer` picks
+at most once per pointer rest.
+
+The slow pick is the first pick after a layer appears, once per page load, most
+likely the pick shader compiling, and its stack is CCTV's own hover pick
+(`src/layers/cctv/hover.js`). No fix is proposed: removing the dwell pick would
+only move the one-off cost to the next click.
+
+### 11. CCTV still-image cameras
+
+`src/layers/cctv/projection.js` holds continuous rendering for as long as any
+projected camera is active and redraws the projection every frame.
+
+Fix: hold only for video. For a still image, request one render when a new image
+lands or while a focus fade runs.
+
+### 12. `/api/firms`
+
+`server/providers/firms.js` builds the payload and calls `JSON.stringify` per
+request, with no kept body and no compression, and the client refetches every
+ten minutes.
+
+Fix: keep the response bytes and their gzip and serve those, as the OpenSky
+provider does. The route filters to the trailing 24 hours at serve time, so the
+bytes can only be reused while that filter keeps the same records (about a
+minute at a time): bursts and several clients gain most, and every response is
+about seven times smaller.
+
+### 13. AIS store
+
+`server/providers/vessels/ais-store.js` calls `pruneAisStreamCache()` for every
+message; the static-data map is never pruned.
+
+Fix: prune on a timer, evict in insertion order, and drop a vessel's static
+entry with the vessel.
+
+### 14. Satellite clouds on the 3D Tiles map
+
+`src/layers/weather/infraredImage.js` runs `getImageData`, a per-pixel power
+curve and `putImageData` over the whole canvas.
+
+Fix: a 256-entry lookup table applied in place for the canvas path, which
+halves it; then, for the shell on the 3D Tiles map, the same curve in its
+fragment shader from a strength uniform, so the image is never read back and a
+strength change builds no new image.
+
+### 15. NVG and FLIR styles
+
+`src/styles/surveillance.js` loops 11 x 11 texture reads per pixel and
+`src/styles/thermal.js` totals 106. Timed on the GPU, those loops cost about
+0.4 ms a frame at 1440 x 900 and 1.2 ms at 2560 x 1440 on the test machine:
+real, but small there. The standing cost is that a style with animated grain
+holds continuous rendering at 60 frames a second.
+
+Fix: split the bloom into a row pass and a column pass, which gives the same
+picture from a fifth to a half of the reads, and step the grain's clock at
+15 Hz, asking for one frame per step instead of holding the render loop. The
+grain then changes 15 times a second, which is visible in motion.
+
+Switching on any style stage at all costs more than the bloom did (1.8 ms a
+frame at 1440 x 900 for the one-line noir style). That was not looked into.
+
+### 16. Wind server
+
+`server/providers/wind/decode.js` decodes about a million doubles per message
+synchronously, hourly, for six keys.
+
+Fix: decode on a worker thread, and keep the sampled U and V of the last
+forecast file per model so that choosing an overlay fetches only its field.
+
+### 17. Per-feature ground clamps
+
+`heightReference: CLAMP_TO_GROUND` per feature is also set in
+`installations/rendering.js`, `alpr/presentation.js`, `ghostMaps/index.js`,
+`earthquakes/index.js`, `airQuality/index.js`, `news/index.js` and
+`osmPlaces/index.js`. Their counts were small in these runs (30 to 1,500) and
+none froze.
+
+Imported geo files were the one unbounded case, and measuring them cleared
+them: 20,000 generated points (the import cap) finish in about 1.5 s with a
+longest task near 0.5 s, because `settleGroundPins` in
+`src/data/geoFileImport.js` already places pins with `HeightReference.NONE` and
+resolves heights 256 at a time with a yield between batches. No fix is needed.
+
+## Checked and fine
+
+- Start-up of a production build: viewer ready in about 0.5 s, loading screen
+  gone at 1.6 s, three long tasks totalling about 300 ms.
+- Idle: no frames rendered with no layers on; every render hold was released
+  when its layer went off.
+- Leaks: all 41 layers toggled three times and ten of them eight times; no
+  timer, scene listener, primitive or data source grew per cycle. The heap
+  levelled off near 320 MB over 7.5 minutes of toggling eleven layers.
+- At most one long task after load: Military, Satellites (including 11,903
+  Starlink points), Earthquakes, News, Wildlife, GNSS, Drone Airspace, Military
+  Installations, Fire Perimeters, rain radar, lightning, and satellite clouds on
+  the globe map.
+- Live Flights at city scale with the same 7,500 aircraft loaded: 60 fps, no
+  long tasks.
+
+## Not covered
+
+- Google Photorealistic 3D Tiles: nothing was run there. Depth sampling is the
+  only height source on that map, so findings 4, 5 and 17 may be worse.
+- Live Vessels, FIRMS with data, TomTom traffic, Local ADS-B.
+- Frame rate on anything but one Apple silicon machine.
+- One all-layers run over Manhattan grew the heap from 346 to 638 MB in 60 s;
+  whether that is retained was not established.
+- One Satellites load showed a 5.2 s long task once and never again in four more
+  loads.

docs/PERFORMANCE.md

@@ -6,6 +6,9 @@ specification and should not be used to predict performance on untested systems.
 The original capture artifacts are not included here, so this page records
 results rather than defining a runnable benchmark.
 
+For slowdowns found since, with their causes and fixes, see
+[PERFORMANCE-AUDIT-2026-11.md](PERFORMANCE-AUDIT-2026-11.md).
+
 ## Test context
 
 The baseline was captured on 22 August 2026 with these conditions:

src/data/telegeographySubmarineCables.js

@@ -24,6 +24,7 @@ export {
   createCableOverlayEntry,
   cableClassificationTypeForStack,
   cableClassificationTypeForScene,
+  applyTranslucentMarkerBlend,
   createCableReferenceSweepGate,
   updateCableReferenceStem,
 } from '../layers/submarineCables/index.js';

src/layers/submarineCables/geometry.js

@@ -77,58 +77,3 @@ export function normalizeFeatures(json, kind) {
     };
   });
 }
-
-function partPosition(value) {
-  if (!Array.isArray(value)) return null;
-  const lon = Number(value[0]);
-  const lat = Number(value[1]);
-  if (!Number.isFinite(lon) || !Number.isFinite(lat)) return null;
-  const height = Number(value[2]);
-  return Number.isFinite(height) ? [lon, lat, height] : [lon, lat];
-}
-
-function collectParts(geometry, out) {
-  const coordinates = geometry?.coordinates;
-  switch (geometry?.type) {
-    case 'Point': {
-      const point = partPosition(coordinates);
-      if (point) out.points.push(point);
-      break;
-    }
-    case 'MultiPoint':
-      for (const value of coordinates || []) {
-        const point = partPosition(value);
-        if (point) out.points.push(point);
-      }
-      break;
-    case 'LineString': {
-      const line = (coordinates || []).map(partPosition).filter(Boolean);
-      if (line.length >= 2) out.lines.push(line);
-      break;
-    }
-    case 'MultiLineString':
-      for (const part of coordinates || []) {
-        const line = (part || []).map(partPosition).filter(Boolean);
-        if (line.length >= 2) out.lines.push(line);
-      }
-      break;
-    case 'GeometryCollection':
-      for (const child of geometry.geometries || []) collectParts(child, out);
-      break;
-    default:
-      break;
-  }
-}
-
-/**
- * The parts of a feature the layer draws: every line of a LineString or
- * MultiLineString and every point of a Point or MultiPoint, also inside a
- * GeometryCollection. Each is [lon, lat] or [lon, lat, height] in degrees
- * and metres. Polygons are not drawn.
- * @returns {{lines:number[][][],points:number[][]}}
- */
-export function featureParts(feature) {
-  const out = { lines: [], points: [] };
-  collectParts(feature?.geometry, out);
-  return out;
-}

src/layers/submarineCables/index.js

@@ -10,7 +10,6 @@ export function createSubmarineCableLayer({
   screenSpaceEventHandlerFactory,
   mapStackEventTarget = null,
   sweepClock = defaultSweepClock,
-  createMarkerImage,
 }) {
   if (!source?.fetch || !source.label)
     throw new TypeError(
@@ -24,7 +23,6 @@ export function createSubmarineCableLayer({
     source,
     screenSpaceEventHandlerFactory,
     mapStackEventTarget,
-    createMarkerImage,
   };
   parts.rendering = createRendering(context);
   parts.ingestion = createIngestion(context);
@@ -42,6 +40,7 @@ export {
 export {
   cableClassificationTypeForStack,
   cableClassificationTypeForScene,
+  applyTranslucentMarkerBlend,
 } from './surface.js';
 export {
   CABLE_REFERENCE_LABEL_WINNER_CAP,

src/layers/submarineCables/ingestion.js

@@ -1,82 +1,27 @@
 import { msg, t } from '../../i18n/index.js';
 import {
   featureLabel,
-  featureParts,
   featureReference,
   normalizeFeatures,
 } from './geometry.js';
 import * as Cesium from 'cesium';
 
-const toCartesian = ([lon, lat, height]) =>
-  Cesium.Cartesian3.fromDegrees(lon, lat, height ?? 0);
+const SOURCE_FEATURE_INDEX = '__gevSourceFeatureIndex';
+
+function indexedCollection(features) {
+  return {
+    type: 'FeatureCollection',
+    features: features.map((feature, index) => ({
+      ...feature,
+      properties: {
+        ...feature.properties,
+        [SOURCE_FEATURE_INDEX]: index,
+      },
+    })),
+  };
+}
 
 export function createIngestion({ state, parts, source }) {
-  /**
-   * Turn the two feature collections into what rendering draws. Every part
-   * of a multipart feature is its own line or marker with its own pick
-   * record, all sharing the feature's reference; a feature gets one
-   * reference stem however many parts it has.
-   */
-  function describeScene(cableFeatures, landingFeatures) {
-    const lines = [];
-    const markers = [];
-    const references = [];
-    const add = (features, kind, style) => {
-      for (const feature of features) {
-        const reference = featureReference(feature);
-        if (!reference) continue;
-        const label = featureLabel(feature);
-        const base = Cesium.Cartesian3.fromDegrees(
-          reference.lon,
-          reference.lat,
-          0,
-        );
-        const drawn = featureParts(feature);
-        const pick = () =>
-          parts.interaction.registerPick({ kind, reference, label });
-        for (const line of drawn.lines)
-          lines.push({
-            info: pick(),
-            base,
-            positions: line.map(toCartesian),
-            color: style.lineColor(feature),
-            width: style.lineWidth,
-          });
-        for (const point of drawn.points)
-          markers.push({
-            info: pick(),
-            base,
-            position: toCartesian(point),
-            hasHeight: point.length > 2,
-            color: style.color,
-          });
-        references.push({
-          reference,
-          label,
-          kind,
-          color: style.color,
-          feature,
-        });
-      }
-    };
-    add(cableFeatures, 'cable', {
-      color: state.cableColor,
-      lineWidth: 2.5,
-      lineColor: (feature) => {
-        const css = feature?.properties?.color;
-        const color = css && Cesium.Color.fromCssColorString(String(css));
-        return (color || state.cableColor).withAlpha(0.92);
-      },
-    });
-    const landingLine = state.landingColor.withAlpha(0.9);
-    add(landingFeatures, 'landing-point', {
-      color: state.landingColor,
-      lineWidth: 2,
-      lineColor: () => landingLine,
-    });
-    return { lines, markers, references };
-  }
-
   async function load(viewer) {
     if (state._loading || state._loaded) return;
 
@@ -85,10 +30,10 @@ export function createIngestion({ state, parts, source }) {
     state._loadingLabel = t('loading...');
     // Ownership token (the militaryAwareness activationId pattern): a
     // disable/abort followed by a fresh enable starts a NEWER load while this
-    // one is still settling. The stale load must bail after its await and
+    // one is still settling. The stale load must bail after every await and
     // must never touch shared lifecycle state or the viewer it no longer
     // owns — clearing `_loading`/`_abort` for the successor is how duplicate
-    // or post-destroy primitives would get added.
+    // or post-destroy data sources got added.
     const generation = ++state._loadGeneration;
     const abort = new AbortController();
     state._abort = abort;
@@ -96,34 +41,170 @@ export function createIngestion({ state, parts, source }) {
       generation === state._loadGeneration && !abort.signal.aborted;
 
     try {
-      const { cables: cableJson, landingPoints: landingJson } =
-        await source.fetch(abort.signal);
-      // The fetch is the only await: everything after it runs in this one
-      // turn, so no disable or destroy can land between the ownership check
-      // and the primitives reaching the scene.
-      if (!owns()) return;
-      if (
-        !Array.isArray(cableJson?.features) ||
-        !Array.isArray(landingJson?.features)
-      ) {
-        throw new TypeError(
-          'A cable source must return cables and landingPoints GeoJSON collections',
-        );
+      let cableJson = state._cachedCableJson;
+      let landingJson = state._cachedLandingJson;
+      if (!cableJson || !landingJson) {
+        ({ cables: cableJson, landingPoints: landingJson } = await source.fetch(
+          abort.signal,
+        ));
+        if (!owns()) return;
+        if (
+          !Array.isArray(cableJson?.features) ||
+          !Array.isArray(landingJson?.features)
+        ) {
+          throw new TypeError(
+            'A cable source must return cables and landingPoints GeoJSON collections',
+          );
+        }
+        state._cachedCableJson = cableJson;
+        state._cachedLandingJson = landingJson;
       }
 
       const cableFeatures = normalizeFeatures(cableJson, 'cable');
       const landingFeatures = normalizeFeatures(landingJson, 'landing');
-      try {
-        parts.rendering.buildScene(
-          viewer,
-          describeScene(cableFeatures, landingFeatures),
-        );
-      } catch (error) {
-        // Leave nothing half built in the scene.
-        parts.rendering.destroyScene(viewer);
-        throw error;
+
+      const cableDataSource = await Cesium.GeoJsonDataSource.load(
+        indexedCollection(cableFeatures),
+        {
+          clampToGround: true,
+          stroke: state.cableColor.withAlpha(0.95),
+          fill: state.cableColor.withAlpha(0.18),
+          strokeWidth: 2,
+          markerColor: state.cableColor,
+          markerSize: 6,
+        },
+      );
+      if (!owns()) return;
+      const landingDataSource = await Cesium.GeoJsonDataSource.load(
+        indexedCollection(landingFeatures),
+        {
+          clampToGround: true,
+          stroke: state.landingColor.withAlpha(0.9),
+          fill: state.landingColor.withAlpha(0.35),
+          strokeWidth: 2,
+          markerColor: state.landingColor,
+          markerSize: 6,
+        },
+      );
+      if (!owns()) return;
+
+      cableDataSource.name = `${source.label} Submarine Cables`;
+      landingDataSource.name = `${source.label} Landing Points`;
+      const referenceDataSource = new Cesium.CustomDataSource(
+        `${source.label} Cable References`,
+      );
+      const addedSources = [
+        cableDataSource,
+        landingDataSource,
+        referenceDataSource,
+      ];
+
+      // dataSources.add() is itself an await point: Cesium mutates the
+      // collection on a DEFERRED tick, so a disable/destroy racing this
+      // window finds nothing to remove and the adds still materialize
+      // afterwards. Await every add to settlement (allSettled so a partial
+      // failure cannot leave an unawaited add materializing later), then
+      // re-check ownership. Pinned teardown mechanism: disable/destroy never
+      // wait for in-flight adds — the stale generation's own post-await
+      // check here guarantees cleanup by removing exactly the sources THIS
+      // generation added.
+      const addResults = await Promise.allSettled([
+        viewer.dataSources.add(cableDataSource),
+        viewer.dataSources.add(landingDataSource),
+        viewer.dataSources.add(referenceDataSource),
+      ]);
+      const rejectedAdd = addResults.find(
+        (result) => result.status === 'rejected',
+      );
+      if (!owns() || rejectedAdd) {
+        // Compensate: every add has settled by now, so removal is effective
+        // (a remove inside the deferred window would have been a no-op).
+        // Remove EVERY generation-local source regardless of settle status:
+        // Cesium's add() pushes into the collection BEFORE raising
+        // dataSourceAdded, so a REJECTED add may still have landed its
+        // mutation. remove() of a never-added source is a harmless no-op.
+        for (const source of addedSources) {
+          try {
+            viewer.dataSources.remove(source, true);
+          } catch {
+            /* collection gone */
+          }
+        }
+        if (owns() && rejectedAdd) throw rejectedAdd.reason;
+        return;
       }
 
+      // Await-free commit: the viewer accepted all three sources and this
+      // load still owns the lifecycle.
+      state._cableDataSource = cableDataSource;
+      state._landingDataSource = landingDataSource;
+      state._referenceDataSource = referenceDataSource;
+
+      const cableEntities = state._cableDataSource.entities.values;
+      const landingEntities = state._landingDataSource.entities.values;
+      state._pickByEntity = new WeakMap();
+      state._referenceRecords = [];
+      state._surfaceRecords = [];
+
+      // Cesium expands multipart geometry into several entities and suffixes
+      // colliding IDs. Its copied properties retain this source index even
+      // when a provider has no ID, so every segment keeps the right owner.
+      const cableReferences = new Set();
+      cableEntities.forEach((entity) => {
+        const index = entity.properties?.[SOURCE_FEATURE_INDEX]?.getValue();
+        const feature = cableFeatures[index];
+        const reference = featureReference(feature);
+        if (!reference) return;
+
+        parts.rendering.styleCableEntity(entity, feature);
+        parts.interaction.registerPickEntity(entity, {
+          kind: 'cable',
+          reference,
+          label: featureLabel(feature),
+        });
+        state._surfaceRecords.push({
+          entity,
+          base: Cesium.Cartesian3.fromDegrees(reference.lon, reference.lat, 0),
+        });
+        if (cableReferences.has(index)) return;
+        cableReferences.add(index);
+        parts.rendering.addReferenceStem({
+          reference,
+          label: featureLabel(feature),
+          kind: 'cable',
+          color: state.cableColor,
+          feature,
+        });
+      });
+
+      const landingReferences = new Set();
+      landingEntities.forEach((entity) => {
+        const index = entity.properties?.[SOURCE_FEATURE_INDEX]?.getValue();
+        const feature = landingFeatures[index];
+        const reference = featureReference(feature);
+        if (!reference) return;
+
+        parts.rendering.styleLandingEntity(entity, feature);
+        parts.interaction.registerPickEntity(entity, {
+          kind: 'landing-point',
+          reference,
+          label: featureLabel(feature),
+        });
+        state._surfaceRecords.push({
+          entity,
+          base: Cesium.Cartesian3.fromDegrees(reference.lon, reference.lat, 0),
+        });
+        if (landingReferences.has(index)) return;
+        landingReferences.add(index);
+        parts.rendering.addReferenceStem({
+          reference,
+          label: featureLabel(feature),
+          kind: 'landing-point',
+          color: state.landingColor,
+          feature,
+        });
+      });
+
       state._count = cableFeatures.length + landingFeatures.length;
       state._loaded = true;
       state._lastUpdate = Date.now();

src/layers/submarineCables/interaction.js

@@ -2,10 +2,9 @@ import * as Cesium from 'cesium';
 import { isPointerFree } from '../../data/inputOwnership.js';
 
 export function createInteraction({ state, screenSpaceEventHandlerFactory }) {
-  /** Every drawn part carries its own record as the Cesium pick id. */
-  function registerPick(info) {
-    state._pickRecords.add(info);
-    return info;
+  function registerPickEntity(entity, info) {
+    entity.__gevTeleGeography = info;
+    state._pickByEntity.set(entity, info);
   }
 
   function beginInteraction(viewer) {
@@ -23,8 +22,32 @@ export function createInteraction({ state, screenSpaceEventHandlerFactory }) {
   }
 
   function resolvePickRecord(picked) {
-    const info = picked?.id;
-    return info && state._pickRecords.has(info) ? info : null;
+    if (!picked) return null;
+    const primitive = picked.primitive;
+    if (primitive) {
+      const primitiveInfo = state._pickByEntity.get(primitive);
+      if (primitiveInfo) return primitiveInfo;
+      if (primitive.__gevTeleGeography) return primitive.__gevTeleGeography;
+      if (
+        primitive.id &&
+        typeof primitive.id === 'object' &&
+        primitive.id.reference
+      ) {
+        return primitive.id;
+      }
+    }
+
+    const entity = picked.id;
+    if (entity) {
+      const entityInfo = state._pickByEntity.get(entity);
+      if (entityInfo) return entityInfo;
+      if (entity.__gevTeleGeography) return entity.__gevTeleGeography;
+      if (entity.id && typeof entity.id === 'object' && entity.id.reference) {
+        return entity.id;
+      }
+    }
+
+    return null;
   }
 
   function flyToReference(viewer, reference) {
@@ -47,7 +70,7 @@ export function createInteraction({ state, screenSpaceEventHandlerFactory }) {
     });
   }
   return {
-    registerPick,
+    registerPickEntity,
     beginInteraction,
     resolvePickRecord,
     flyToReference,

src/layers/submarineCables/lifecycle.js

@@ -38,13 +38,12 @@ export function createLifecycle({ state, parts, source, mapStackEventTarget }) {
             // never emit moveEnd — reach the motion fallback. No render is
             // requested for a fallback sweep: it only fires while the camera is
             // already moving, so frames are flowing by construction.
-            if (!state._enabled || !state._loaded) return;
-            // Markers left over from the last sweep, a few per frame; line
-            // shows and rebuilt stems waiting for their geometry.
-            parts.rendering.revealLandingMarkers();
-            parts.rendering.syncLineShow();
-            parts.rendering.settleStems();
-            if (!state._referenceSweepGate.shouldRun(viewer.camera)) return;
+            if (
+              !state._enabled ||
+              !state._loaded ||
+              !state._referenceSweepGate.shouldRun(viewer.camera)
+            )
+              return;
             parts.rendering.updateReferenceVisibility();
           },
         );
@@ -81,15 +80,10 @@ export function createLifecycle({ state, parts, source, mapStackEventTarget }) {
         state._loading = false;
         state._loadingLabel = '';
       }
-      // Hide what is built and keep it: a hidden primitive is skipped by
-      // the scene, so it costs nothing per frame, and the next enable shows
-      // it again without a rebuild. Only the stems go: they are sized for
-      // the view and the next sweep redraws them in a worker. An in-flight load's own post-await
-      // ownership check stops that stale generation from building anything.
-      state._pendingLandingReveals.length = 0;
-      parts.rendering.dropStems();
-      parts.rendering.updateVisibility();
-      state._viewer?.scene?.requestRender?.();
+      // Free the entities rather than hide them; enable() rebuilds from the
+      // cached JSON. An in-flight load's own post-await ownership check
+      // removes whatever that stale generation adds later.
+      parts.rendering.releaseDataSources(state._viewer);
     },
 
     update(viewer) {
@@ -98,7 +92,9 @@ export function createLifecycle({ state, parts, source, mapStackEventTarget }) {
 
     destroy(viewer) {
       if (state._abort) state._abort.abort();
-      parts.rendering.destroyScene(viewer || state._viewer);
+      parts.rendering.releaseDataSources(viewer || state._viewer);
+      state._cachedCableJson = null;
+      state._cachedLandingJson = null;
       // hide() clears every published host entry and goes invisible while
       // keeping the publisher reusable — the legacy layer supported re-init
       // after destroy, and hidden publishers already drop late publishes.
@@ -132,6 +128,16 @@ export function createLifecycle({ state, parts, source, mapStackEventTarget }) {
       state._error = null;
       state._lastUpdate = null;
       state._loadingLabel = '';
+      state._cableDataSource = null;
+      state._landingDataSource = null;
+      state._referenceDataSource = null;
+      state._referenceRecords = [];
+      state._surfaceRecords = [];
+      state._pickByEntity = new WeakMap();
+      state._referenceLabelCount = 0;
+      state._publishScratch.length = 0;
+      state._markerBlendDone = false;
+      state._markerBlendInvariantWarned = false;
       parts.rendering.resetPublishSignature();
       state._referenceSweepGate.reset();
     },

src/layers/submarineCables/overlay.js

@@ -41,7 +41,7 @@ export function selectCableReferenceLabelWinners(
     .sort(
       (a, b) =>
         a.distanceM - b.distanceM ||
-        String(a.id || '').localeCompare(String(b.id || '')),
+        String(a.entity?.id || '').localeCompare(String(b.entity?.id || '')),
     )
     .slice(0, cap);
 }
@@ -248,15 +248,16 @@ export function createCableReferenceSweepGate({
 }
 
 /**
- * Recompute one stem tip on the sweep cadence. The tip is moved in place, so
- * the label entry keeps pointing at it, and only when the camera-scaled tip
- * moved beyond the settle epsilon; the tip point follows with one buffer
- * write, and the caller redraws the stems when any tip moved.
- * @param {object} record Reference record with point/base/tip/nextTip.
+ * Recompute one staticized stem on the sweep cadence. Replaces the former
+ * per-frame `CallbackProperty` pair: constant properties are redefined only
+ * when the camera-scaled tip moved beyond the settle epsilon, and the two
+ * preallocated position buffers alternate so each real change raises exactly
+ * one geometry notification (the localGeojson double-buffer pattern).
+ * @param {object} record Reference record with entity/base/tip/nextTip/buffers.
  * @param {Cesium.Cartesian3} cameraPositionWC
  * @param {number} canvasHeight CSS-pixel canvas height.
  * @param {number} fov Camera frustum field of view (radians).
- * @returns {boolean} True when the tip moved.
+ * @returns {boolean} True when the stem geometry was redefined.
  */
 
 export function updateCableReferenceStem(
@@ -288,7 +289,13 @@ export function updateCableReferenceStem(
     return false;
   }
   Cesium.Cartesian3.clone(record.nextTip, record.tip);
-  record.point.position = record.tip;
+  record.stemPositionBufferIndex = 1 - record.stemPositionBufferIndex;
+  const stemPositions =
+    record.stemPositionBuffers[record.stemPositionBufferIndex];
+  stemPositions[0] = record.base;
+  stemPositions[1] = record.tip;
+  record.entity.position.setValue(record.tip);
+  record.entity.polyline.positions.setValue(stemPositions);
   return true;
 }
 

src/layers/submarineCables/policy.js

@@ -1,3 +1,5 @@
+import * as Cesium from 'cesium';
+
 export const BASE_CABLE_COLOR = '#39d5ff';
 
 export const BASE_LANDING_COLOR = '#8fffd2';
@@ -64,22 +66,6 @@ export const CABLE_LABEL_DEPTH_DECISION = Object.freeze({
   depthTested: false,
 });
 
-/**
- * Landing markers clamped to the ground per rendered frame. A marker is put
- * on the surface the first time it comes into view, and that reads the
- * terrain height under it. Doing it for all 1,917 in the frame after the
- * layer was switched on was a single task (measured 1.2 s on a loaded
- * globe); a few dozen per frame keeps each frame short and the markers still
- * fill in within a second. A marker is clamped once: after that Cesium moves
- * it as terrain loads, and hiding or showing it reads nothing.
- */
-
-export const CABLE_LANDING_REVEALS_PER_FRAME = 48;
-
-/** Pixel size of the marker drawn for point geometry (GeoJSON's small pin). */
-
-export const CABLE_MARKER_SIZE = 6;
-
 /**
  * `MAP_STACKS` ids that render imagery on the SHOWN Cesium globe (the ion
  * Bing stacks + OSM). Deliberately an explicit allowlist, not "anything that
@@ -95,6 +81,19 @@ export const CABLE_GLOBE_STACK_IDS = Object.freeze(
   new Set(['bing-aerial', 'bing-labels', 'esri-imagery', 'osm']),
 );
 
+/** EntityCluster's private marker collections and their required types. */
+
+export const MARKER_COLLECTION_EXPECTATIONS = Object.freeze([
+  Object.freeze({
+    key: '_billboardCollection',
+    type: Cesium.BillboardCollection,
+  }),
+  Object.freeze({
+    key: '_pointCollection',
+    type: Cesium.PointPrimitiveCollection,
+  }),
+]);
+
 /**
  * Monotonic clock for the sweep gate's motion probe. A hoisted declaration:
  * the module's `export default createTeleGeographySubmarineCableLayer()`

src/layers/submarineCables/rendering.js

@@ -1,8 +1,8 @@
 import * as Cesium from 'cesium';
 import {
-  CABLE_LANDING_REVEALS_PER_FRAME,
-  CABLE_MARKER_SIZE,
-} from './policy.js';
+  probeTranslucentMarkerBlend,
+  commitTranslucentMarkerBlend,
+} from './surface.js';
 import {
   clampLabel,
   createCableOverlayEntry,
@@ -11,13 +11,7 @@ import {
   cableReferencePriority,
 } from './overlay.js';
 
-const defaultMarkerImage = (color) =>
-  new Cesium.PinBuilder().fromColor(color, CABLE_MARKER_SIZE);
-
-export function createRendering({
-  state,
-  createMarkerImage = defaultMarkerImage,
-}) {
+export function createRendering({ state }) {
   function resetPublishSignature() {
     state._lastPublishedIds.length = 0;
     state._lastPublishedPriorities.length = 0;
@@ -25,131 +19,129 @@ export function createRendering({
   }
 
   /**
-   * Build everything the layer draws, in one synchronous pass with no entity
-   * per feature. The layer used to load two GeoJsonDataSources and a
-   * CustomDataSource: 6,459 entities whose creation held about 1 GB of
-   * short-lived heap, whose visualizers ran 100–250 ms tasks whenever shows
-   * or stems changed, and whose removal on disable was a 150 ms task. These
-   * are the primitives Cesium built from those entities, made directly:
-   *
-   * - lines: one GroundPolylinePrimitive, a colour and a show flag per line
-   *   (Cesium's own batch for clamped colour polylines), tessellated in a
-   *   worker;
-   * - point markers: one BillboardCollection, each billboard hidden and
-   *   unclamped until revealLandingMarkers puts it on the ground;
-   * - references: one PointPrimitiveCollection for the tips, whose positions
-   *   and shows are plain buffer writes, and one Primitive of polylines for
-   *   the stems (see rebuildStems).
-   *
-   * `lines`, `markers` and `references` come from ingestion; each line and
-   * marker carries the pick record Cesium returns as the pick id.
+   * Remove the three data sources from the viewer and forget the built
+   * entities. Hiding them (`show = false`) is NOT enough: Cesium's
+   * DataSourceDisplay still walks every visualizer of a hidden source on
+   * every frame, and the thousands of hidden polylines/billboards keep
+   * costing CPU and GC pressure long after the user toggled the layer off —
+   * that is the "everything gets sluggish after I turn layers off" report.
+   * The fetched JSON stays cached, so the next enable rebuilds without a
+   * network round trip or a re-parse.
    */
 
-  function buildScene(viewer, { lines, markers, references }) {
-    const scene = viewer.scene;
-    state._lineRecords = [];
-    state._markerRecords = [];
+  function releaseDataSources(viewer) {
+    const sources = [
+      state._cableDataSource,
+      state._landingDataSource,
+      state._referenceDataSource,
+    ];
+    state._cableDataSource = null;
+    state._landingDataSource = null;
+    state._referenceDataSource = null;
     state._referenceRecords = [];
-    state._pendingLandingReveals.length = 0;
-
-    if (lines.length) {
-      // The entity display gave every line this attribute too. It is a float
-      // attribute, and with one present Cesium keeps the per-line width as a
-      // float; without it the 2.5 px width is stored as a byte and draws 2 px.
-      const always =
-        Cesium.DistanceDisplayConditionGeometryInstanceAttribute.fromDistanceDisplayCondition(
-          new Cesium.DistanceDisplayCondition(),
-        );
-      const instances = lines.map(
-        (line) =>
-          new Cesium.GeometryInstance({
-            id: line.info,
-            geometry: new Cesium.GroundPolylineGeometry({
-              positions: line.positions,
-              width: line.width,
-              // GeoJSON lines are rhumb lines (GeoJsonDataSource's choice).
-              arcType: Cesium.ArcType.RHUMB,
-            }),
-            attributes: {
-              color: Cesium.ColorGeometryInstanceAttribute.fromColor(
-                line.color,
-              ),
-              show: new Cesium.ShowGeometryInstanceAttribute(true),
-              distanceDisplayCondition: always,
-            },
-          }),
-      );
-      state._cablePrimitive = scene.groundPrimitives.add(
-        new Cesium.GroundPolylinePrimitive({
-          geometryInstances: instances,
-          appearance: new Cesium.PolylineColorAppearance(),
-          classificationType: state._classificationType,
-          asynchronous: true,
-          show: state._enabled,
-        }),
-      );
-      for (const line of lines)
-        state._lineRecords.push({
-          info: line.info,
-          base: line.base,
-          visible: true,
-          shown: true,
-          attributes: null,
-        });
-    }
-
-    if (markers.length) {
-      // Every marker is translucent, so one blend pass, not Cesium's two.
-      const billboards = scene.primitives.add(
-        new Cesium.BillboardCollection({
-          scene,
-          blendOption: Cesium.BlendOption.TRANSLUCENT,
-          show: state._enabled,
-        }),
-      );
-      state._markerBillboards = billboards;
-      const images = new Map();
-      for (const marker of markers) {
-        const key = marker.color.toCssHexString();
-        let image = images.get(key);
-        if (!image) {
-          image = {
-            id: `gev-cable-marker-${key}`,
-            source: createMarkerImage(marker.color),
-          };
-          images.set(key, image);
-        }
-        const billboard = billboards.add({
-          id: marker.info,
-          position: marker.position,
-          verticalOrigin: Cesium.VerticalOrigin.BOTTOM,
-          show: false,
-        });
-        billboard.setImage(image.id, image.source);
-        state._markerRecords.push({
-          info: marker.info,
-          marker: billboard,
-          base: marker.base,
-          // A position with its own height is drawn there, as before.
-          clamped: marker.hasHeight,
-          visible: false,
-        });
+    state._surfaceRecords = [];
+    state._pickByEntity = new WeakMap();
+    state._referenceLabelCount = 0;
+    state._publishScratch.length = 0;
+    // The blend pass targets the collections being dropped; the rebuilt
+    // sources need their own pass.
+    state._markerBlendDone = false;
+    state._loaded = false;
+    state._referenceSweepGate.reset();
+    for (const source of sources) {
+      if (!source) continue;
+      try {
+        viewer?.dataSources?.remove(source, true);
+      } catch {
+        /* collection gone */
       }
     }
+  }
 
-    if (references.length) {
-      state._referencePoints = scene.primitives.add(
-        new Cesium.PointPrimitiveCollection({
-          blendOption: Cesium.BlendOption.TRANSLUCENT,
-          show: state._enabled,
-        }),
-      );
-      for (const reference of references) addReferenceStem(reference);
+  function updateVisibility() {
+    if (state._cableDataSource) state._cableDataSource.show = state._enabled;
+    if (state._landingDataSource)
+      state._landingDataSource.show = state._enabled;
+    if (state._referenceDataSource)
+      state._referenceDataSource.show = state._enabled;
+  }
+
+  function styleCableEntity(entity, feature) {
+    if (!entity?.polyline) return;
+    const color = feature?.properties?.color
+      ? Cesium.Color.fromCssColorString(String(feature.properties.color))
+      : state.cableColor;
+    entity.polyline.material = color.withAlpha(0.92);
+    entity.polyline.width = 2.5;
+    entity.polyline.clampToGround = true;
+    entity.polyline.classificationType = state._classificationType;
+    entity.show = true;
+  }
+
+  /**
+   * Apply the single translucent blend pass to the landing-billboard and
+   * reference-point collections. Landing entities carry only billboards and
+   * reference entities only points, so completion is one applied collection
+   * per source; a failed shape probe disables the optimization permanently
+   * for this session and says so loudly in dev builds.
+   * Both sources are probed BEFORE either is committed, so the helper's
+   * "defaults untouched on shape drift" fallback holds across the pair too —
+   * a reference-source failure can never leave the landing source already
+   * forced to TRANSLUCENT.
+   */
+
+  function applyMarkerBlendOnce() {
+    const landing = probeTranslucentMarkerBlend(state._landingDataSource);
+    const reference = probeTranslucentMarkerBlend(state._referenceDataSource);
+    if (landing.invariantFailed || reference.invariantFailed) {
+      state._markerBlendDone = true;
+      if (!state._markerBlendInvariantWarned && import.meta.env?.DEV === true) {
+        state._markerBlendInvariantWarned = true;
+        console.error(
+          '[Data:telegeography-submarine-cables] EntityCluster marker-collection ' +
+            'shape changed — single-pass translucent blend skipped; markers fall ' +
+            "back to Cesium's default two-pass blend.",
+        );
+      }
+      return;
     }
-    state._lineShowDirty = false;
+    const landingBlend = commitTranslucentMarkerBlend(landing);
+    const referenceBlend = commitTranslucentMarkerBlend(reference);
+    if (landingBlend.applied > 0 && referenceBlend.applied > 0)
+      state._markerBlendDone = true;
+  }
+
+  /**
+   * Re-classify every cable ground line for the active surface. One batched
+   * ground-primitive rebuild per stack switch — never per frame.
+   * @param {Cesium.ClassificationType} next
+   */
+
+  function applyCableClassification(next) {
+    if (next === undefined || next === state._classificationType) return;
+    state._classificationType = next;
+    if (!state._cableDataSource) return;
+    const entities = state._cableDataSource.entities.values;
+    for (let i = 0; i < entities.length; i++) {
+      const polyline = entities[i].polyline;
+      if (polyline) polyline.classificationType = next;
+    }
+    state._viewer?.scene?.requestRender?.();
+  }
+
+  function styleLandingEntity(entity, feature) {
+    if (!entity?.point) return;
+    entity.point.color = state.landingColor.withAlpha(0.92);
+    entity.point.pixelSize = feature?.properties?.is_tbd ? 6 : 7;
+    entity.point.outlineColor = state.cableOutline;
+    entity.point.outlineWidth = 1;
+    entity.point.disableDepthTestDistance = 0;
+    entity.show = true;
   }
 
   function addReferenceStem({ reference, label, kind, color, feature }) {
+    if (!state._referenceDataSource || !reference) return;
+
     const base = Cesium.Cartesian3.fromDegrees(reference.lon, reference.lat, 0);
     const tip = Cesium.Cartesian3.fromDegrees(
       reference.lon,
@@ -162,31 +154,42 @@ export function createRendering({
       label,
       featureId: feature?.id || feature?.properties?.id || null,
     };
-    state._pickRecords.add(info);
     const pointColor = color.withAlpha(kind === 'cable' ? 0.84 : 0.94);
-    // The tip is moved in place on the sweep cadence (overlay.js), never by a
-    // per-frame callback.
-    const point = state._referencePoints.add({
-      id: info,
-      position: tip,
-      pixelSize: kind === 'cable' ? 7 : 8,
-      color: pointColor,
-      outlineColor: Cesium.Color.BLACK.withAlpha(0.65),
-      outlineWidth: 1,
-      disableDepthTestDistance: 0,
-      show: false,
-    });
-    const record = {
+    const stemColor = color.withAlpha(kind === 'cable' ? 0.58 : 0.68);
+    // Constant properties on the sweep cadence, never per-frame callbacks:
+    // the sweep redefines them through the alternating buffers below.
+    const stemPositionBuffers = [
+      [base, tip],
+      [base, tip],
+    ];
+
+    const entity = state._referenceDataSource.entities.add({
       id: `${kind}-reference-${state._referenceRecords.length}-${info.featureId || 'feature'}`,
-      info,
-      point,
+      position: tip,
+      polyline: {
+        positions: stemPositionBuffers[0],
+        width: kind === 'cable' ? 2 : 2.4,
+        material: new Cesium.ColorMaterialProperty(stemColor),
+      },
+      point: {
+        pixelSize: kind === 'cable' ? 7 : 8,
+        color: pointColor,
+        outlineColor: Cesium.Color.BLACK.withAlpha(0.65),
+        outlineWidth: 1,
+        disableDepthTestDistance: 0,
+      },
+    });
+
+    entity.__gevTeleGeography = info;
+    state._pickByEntity.set(entity, info);
+    const record = {
+      id: entity.id,
+      entity,
       base,
       tip,
       nextTip: Cesium.Cartesian3.clone(tip),
-      stemColor: Cesium.ColorGeometryInstanceAttribute.fromColor(
-        color.withAlpha(kind === 'cable' ? 0.58 : 0.68),
-      ),
-      stemWidth: kind === 'cable' ? 2 : 2.4,
+      stemPositionBuffers,
+      stemPositionBufferIndex: 0,
       reference,
       kind,
       label: clampLabel(label),
@@ -198,212 +201,6 @@ export function createRendering({
     state._referenceRecords.push(record);
   }
 
-  /**
-   * Draw the stems of the references now in view, base to tip. Stems are one
-   * static polyline primitive, as the entity display batched them: nothing
-   * runs for it per frame, and a stem's length cannot change without new
-   * geometry. So a sweep that moved a tip or changed which references are
-   * in view builds a replacement in a worker, and settleStems swaps it in
-   * once it is ready; the previous stems stay until then. A sweep that
-   * changed nothing builds nothing.
-   */
-
-  function rebuildStems() {
-    const primitives = state._viewer?.scene?.primitives;
-    if (!primitives) return;
-    if (state._stemPrimitivePending) {
-      // Superseded before it was ever shown.
-      primitives.remove(state._stemPrimitivePending);
-      state._stemPrimitivePending = null;
-    }
-    const instances = [];
-    for (const record of state._referenceRecords) {
-      if (!record.visible) continue;
-      instances.push(
-        new Cesium.GeometryInstance({
-          id: record.info,
-          geometry: new Cesium.PolylineGeometry({
-            positions: [record.base, record.tip],
-            width: record.stemWidth,
-            vertexFormat: Cesium.PolylineColorAppearance.VERTEX_FORMAT,
-          }),
-          attributes: { color: record.stemColor },
-        }),
-      );
-    }
-    state._stemsDirty = false;
-    if (!instances.length) {
-      if (state._stemPrimitive) primitives.remove(state._stemPrimitive);
-      state._stemPrimitive = null;
-      return;
-    }
-    state._stemPrimitivePending = primitives.add(
-      new Cesium.Primitive({
-        geometryInstances: instances,
-        appearance: new Cesium.PolylineColorAppearance({ translucent: true }),
-        asynchronous: true,
-        // Hidden while it builds; settleStems shows it.
-        show: false,
-      }),
-    );
-    state._viewer.scene.requestRender?.();
-  }
-
-  /** Swap in rebuilt stems once their geometry is ready; called per frame. */
-
-  function settleStems() {
-    const pending = state._stemPrimitivePending;
-    if (!pending) return;
-    const scene = state._viewer?.scene;
-    if (!pending.ready) {
-      // Keep frames coming until the geometry is in.
-      scene?.requestRender?.();
-      return;
-    }
-    pending.show = state._enabled;
-    if (state._stemPrimitive) scene?.primitives?.remove(state._stemPrimitive);
-    state._stemPrimitive = pending;
-    state._stemPrimitivePending = null;
-    scene?.requestRender?.();
-  }
-
-  /** Remove and destroy everything buildScene made. Only destroy() does this;
-   * a disable hides the primitives and keeps them for the next enable. */
-
-  function destroyScene(viewer) {
-    const scene = viewer?.scene;
-    const owned = [
-      [scene?.groundPrimitives, state._cablePrimitive],
-      [scene?.primitives, state._markerBillboards],
-      [scene?.primitives, state._stemPrimitive],
-      [scene?.primitives, state._stemPrimitivePending],
-      [scene?.primitives, state._referencePoints],
-    ];
-    state._cablePrimitive = null;
-    state._markerBillboards = null;
-    state._stemPrimitive = null;
-    state._stemPrimitivePending = null;
-    state._stemsDirty = false;
-    state._referencePoints = null;
-    state._referenceRecords = [];
-    state._lineRecords = [];
-    state._markerRecords = [];
-    state._lineShowDirty = false;
-    state._pendingLandingReveals.length = 0;
-    state._pickRecords = new WeakSet();
-    state._referenceLabelCount = 0;
-    state._publishScratch.length = 0;
-    state._loaded = false;
-    state._referenceSweepGate.reset();
-    for (const [collection, primitive] of owned) {
-      if (!primitive) continue;
-      try {
-        // A collection destroys what it removes; one that is already gone
-        // has destroyed it too.
-        if (!collection?.remove?.(primitive) && !primitive.isDestroyed())
-          primitive.destroy();
-      } catch {
-        /* collection gone */
-      }
-    }
-  }
-
-  /**
-   * Drop the stems, shown and building, so the next sweep draws them afresh.
-   * A disable does this: stems kept from the view the layer was switched off
-   * in would show at their old lengths until the rebuild for the new view
-   * was ready.
-   */
-
-  function dropStems() {
-    const primitives = state._viewer?.scene?.primitives;
-    for (const primitive of [state._stemPrimitive, state._stemPrimitivePending])
-      if (primitive) primitives?.remove(primitive);
-    state._stemPrimitive = null;
-    state._stemPrimitivePending = null;
-    state._stemsDirty = true;
-  }
-
-  function updateVisibility() {
-    for (const primitive of [
-      state._cablePrimitive,
-      state._markerBillboards,
-      state._stemPrimitive,
-      state._referencePoints,
-    ])
-      if (primitive) primitive.show = state._enabled;
-  }
-
-  /**
-   * Re-classify the cable ground lines for the active surface. The primitive
-   * reads its classification as it queues commands, so this is one
-   * assignment per stack switch and no rebuild.
-   * @param {Cesium.ClassificationType} next
-   */
-
-  function applyCableClassification(next) {
-    if (next === undefined || next === state._classificationType) return;
-    state._classificationType = next;
-    if (!state._cablePrimitive) return;
-    state._cablePrimitive.classificationType = next;
-    state._viewer?.scene?.requestRender?.();
-  }
-
-  /**
-   * Write the line show states the last sweep worked out. The primitive
-   * builds its geometry in a worker and has no per-line attributes until it
-   * is ready, so the states wait in the records until then.
-   */
-
-  function syncLineShow() {
-    if (!state._lineShowDirty) return;
-    const primitive = state._cablePrimitive;
-    if (!primitive?.ready) {
-      // Keep frames coming until the geometry is in.
-      if (primitive) state._viewer?.scene?.requestRender?.();
-      return;
-    }
-    for (const record of state._lineRecords) {
-      if (record.shown === record.visible) continue;
-      record.attributes ??= primitive.getGeometryInstanceAttributes(
-        record.info,
-      );
-      if (!record.attributes) continue;
-      record.attributes.show = Cesium.ShowGeometryInstanceAttribute.toValue(
-        record.visible,
-        record.attributes.show,
-      );
-      record.shown = record.visible;
-    }
-    state._lineShowDirty = false;
-  }
-
-  /**
-   * Put the next few markers the last sweep found visible on the ground and
-   * show them, and ask for another frame while any are left. Called from the
-   * sweep and then once per rendered frame, so a parked camera costs nothing
-   * once the list is empty. Clamping is what reads the terrain height, once
-   * per marker; Cesium then keeps the marker on the surface as terrain loads,
-   * within its own per-frame time budget.
-   */
-
-  function revealLandingMarkers() {
-    const pending = state._pendingLandingReveals;
-    if (!pending.length) return;
-    let budget = CABLE_LANDING_REVEALS_PER_FRAME;
-    while (pending.length && budget > 0) {
-      const record = pending.pop();
-      if (!record.visible || record.marker.show) continue;
-      if (!record.clamped) {
-        record.marker.heightReference = Cesium.HeightReference.CLAMP_TO_GROUND;
-        record.clamped = true;
-        budget--;
-      }
-      record.marker.show = true;
-    }
-    if (pending.length) state._viewer?.scene?.requestRender?.();
-  }
-
   function updateReferenceVisibility() {
     if (!state._enabled || !state._viewer?.camera) return;
     const cameraPos = state._viewer.camera.positionWC;
@@ -419,35 +216,20 @@ export function createRendering({
       const visible = occluder.isPointVisible(record.base);
       record.visible = visible;
       record.distanceM = Cesium.Cartesian3.distance(cameraPos, record.base);
-      if (record.point.show !== visible) {
-        record.point.show = visible;
-        state._stemsDirty = true;
+      if (record.entity.show !== visible) {
+        record.entity.show = visible;
       }
-      // Hidden stems keep their last tip; this same sweep refreshes them in
-      // the pass where they turn visible again.
-      if (
-        visible &&
-        updateCableReferenceStem(record, cameraPos, canvasHeight, fov)
-      )
-        state._stemsDirty = true;
+      // Hidden stems keep their last geometry; this same sweep refreshes them
+      // in the pass where they turn visible again.
+      if (visible)
+        updateCableReferenceStem(record, cameraPos, canvasHeight, fov);
     }
-    if (state._stemsDirty) rebuildStems();
-    for (const record of state._lineRecords) {
-      record.visible = occluder.isPointVisible(record.base);
-      if (record.visible !== record.shown) state._lineShowDirty = true;
-    }
-    syncLineShow();
-    state._pendingLandingReveals.length = 0;
-    for (const record of state._markerRecords) {
+    for (const record of state._surfaceRecords) {
       const visible = occluder.isPointVisible(record.base);
-      record.visible = visible;
-      if (record.marker.show === visible) continue;
-      // A marker not yet on the ground waits its turn; one that already is
-      // shows at once, and hiding is immediate.
-      if (visible && !record.clamped) state._pendingLandingReveals.push(record);
-      else record.marker.show = visible;
+      if (record.entity.show !== visible) {
+        record.entity.show = visible;
+      }
     }
-    revealLandingMarkers();
     const winners = selectCableReferenceLabelWinners(state._referenceRecords);
     let changed = winners.length !== state._lastPublishedCount;
     for (let i = 0; i < winners.length; i++) {
@@ -465,6 +247,9 @@ export function createRendering({
     }
     state._publishScratch.length = winners.length;
     state._referenceLabelCount = winners.length;
+    // The marker collections are created lazily by the visualizers, so the
+    // single-pass blend is applied on the sweep cadence until both landed.
+    if (!state._markerBlendDone) applyMarkerBlendOnce();
     if (!changed) return;
     state._overlayPublisher.publish(state._publishScratch);
     state._lastPublishedCount = winners.length;
@@ -477,14 +262,13 @@ export function createRendering({
   }
   return {
     resetPublishSignature,
-    buildScene,
-    destroyScene,
+    releaseDataSources,
     updateVisibility,
+    styleCableEntity,
+    applyMarkerBlendOnce,
     applyCableClassification,
-    syncLineShow,
-    settleStems,
-    dropStems,
-    revealLandingMarkers,
+    styleLandingEntity,
+    addReferenceStem,
     updateReferenceVisibility,
   };
 }

src/layers/submarineCables/state.js

@@ -30,50 +30,26 @@ export function createState({ sweepClock, overlayHost }) {
 
   state._loadGeneration = 0;
 
+  state._cableDataSource = null;
+
+  state._landingDataSource = null;
+
+  state._referenceDataSource = null;
+
   /**
-   * What the layer draws, built once per load and kept across disable/enable
-   * (a disable only hides them, which costs nothing per frame):
-   * one ground polyline primitive for every line, one billboard collection
-   * for every point marker, a point collection for the reference tips and
-   * one polyline primitive for the reference stems.
+   * Fetched cable/landing JSON kept across disable/enable. A disable RELEASES
+   * the three data sources (see releaseDataSources) instead of hiding them,
+   * so a re-enable has to rebuild the entities; the network/parse half of
+   * that rebuild is the expensive part users would notice, so it is cached.
    */
 
-  state._cablePrimitive = null;
+  state._cachedCableJson = null;
 
-  state._markerBillboards = null;
-
-  state._referencePoints = null;
-
-  /** The stems now drawn, and their replacement while it builds. */
-
-  state._stemPrimitive = null;
-
-  state._stemPrimitivePending = null;
-
-  state._stemsDirty = false;
+  state._cachedLandingJson = null;
 
   state._referenceRecords = [];
 
-  /** One record per drawn line: its pick record, horizon base and show state. */
-
-  state._lineRecords = [];
-
-  /** Line show states still to be written once the primitive is ready. */
-
-  state._lineShowDirty = false;
-
-  /** One record per point marker: its billboard and horizon base. */
-
-  state._markerRecords = [];
-
-  /** Markers the last sweep found visible but not on the ground yet; drained
-   * a few per frame (CABLE_LANDING_REVEALS_PER_FRAME). */
-
-  state._pendingLandingReveals = [];
-
-  /** The pick records handed to Cesium as ids, so a pick is known to be ours. */
-
-  state._pickRecords = new WeakSet();
+  state._surfaceRecords = [];
 
   state._clickHandler = null;
 
@@ -87,6 +63,14 @@ export function createState({ sweepClock, overlayHost }) {
 
   state._classificationType = Cesium.ClassificationType.BOTH;
 
+  /** True once both marker collections blend translucent (or the shape probe failed). */
+
+  state._markerBlendDone = false;
+
+  state._markerBlendInvariantWarned = false;
+
+  state._pickByEntity = new WeakMap();
+
   state._referenceLabelCount = 0;
 
   state._referenceSweepGate = createCableReferenceSweepGate({

src/layers/submarineCables/surface.js

@@ -1,5 +1,8 @@
 import * as Cesium from 'cesium';
-import { CABLE_GLOBE_STACK_IDS } from './policy.js';
+import {
+  CABLE_GLOBE_STACK_IDS,
+  MARKER_COLLECTION_EXPECTATIONS,
+} from './policy.js';
 
 /**
  * Ground-line classification for one map stack. The photoreal stack renders
@@ -7,7 +10,7 @@ import { CABLE_GLOBE_STACK_IDS } from './policy.js';
  * need the 3D-tile classification pass there; every other known stack (the
  * bing stacks and osm) renders imagery on the shown globe, so only the
  * terrain pass applies.
- * Classifying against just the active surface halves the
+ * Classifying against just the active surface halves the batched
  * GroundPolylinePrimitive's emitted command sets. BOTH is the safe fallback
  * for an unknown stack — it renders on every surface, exactly the shipped
  * pre-optimization behavior.
@@ -37,3 +40,87 @@ export function cableClassificationTypeForScene(scene) {
     ? Cesium.ClassificationType.CESIUM_3D_TILE
     : Cesium.ClassificationType.TERRAIN;
 }
+
+/**
+ * Validate one data source's marker collections WITHOUT mutating anything.
+ * Splitting validation from mutation is what makes the fallback honest: a
+ * shape failure on the SECOND collection (or the second data source) must
+ * not leave the first one already forced to TRANSLUCENT.
+ * @param {Cesium.DataSource|null|undefined} dataSource
+ * @returns {{ready:object[],pending:number,invariantFailed:boolean}}
+ */
+
+export function probeTranslucentMarkerBlend(dataSource) {
+  const cluster = dataSource?.clustering;
+  if (!cluster) return { ready: [], pending: 0, invariantFailed: true };
+  const ready = [];
+  let pending = 0;
+  let invariantFailed = false;
+  for (const { key, type } of MARKER_COLLECTION_EXPECTATIONS) {
+    if (!(key in cluster)) {
+      invariantFailed = true;
+      continue;
+    }
+    const collection = cluster[key];
+    if (collection === undefined || collection === null) {
+      pending++;
+      continue;
+    }
+    if (!(collection instanceof type) || !('blendOption' in collection)) {
+      invariantFailed = true;
+      continue;
+    }
+    ready.push(collection);
+  }
+  // Any failure discards every collected target: nothing is mutated at all.
+  if (invariantFailed) return { ready: [], pending: 0, invariantFailed: true };
+  return { ready, pending, invariantFailed: false };
+}
+
+/**
+ * Commit a clean probe. Only ever called once every probe in the batch has
+ * passed, so this cannot land a partial application.
+ * @param {{ready:object[],pending:number}} probe
+ * @returns {{applied:number,pending:number,invariantFailed:boolean}}
+ */
+
+export function commitTranslucentMarkerBlend(probe) {
+  for (const collection of probe.ready) {
+    if (collection.blendOption !== Cesium.BlendOption.TRANSLUCENT) {
+      collection.blendOption = Cesium.BlendOption.TRANSLUCENT;
+    }
+  }
+  return {
+    applied: probe.ready.length,
+    pending: probe.pending,
+    invariantFailed: false,
+  };
+}
+
+/**
+ * Force one translucent draw pass for a data source's marker collections.
+ * The default `OPAQUE_AND_TRANSLUCENT` blend emits two draw commands per
+ * collection, and every cable marker is translucent (alpha < 1), so the
+ * opaque pass is pure overhead across 1,917 landing billboards + 2,629
+ * reference points. Cesium has no public accessor for the entity-backed
+ * collections, so this reaches through EntityCluster's private fields under
+ * a SHAPE INVARIANT the caller must honor loudly: the constructor
+ * pre-assigns `_billboardCollection`/`_pointCollection` (= undefined until a
+ * visualizer lazily creates them), so a missing PROPERTY means Cesium's
+ * shape changed — report `invariantFailed` and never touch anything —
+ * while a present-but-undefined value only means "not created yet"
+ * (`pending`). Wrong instance types also fail the invariant. The cables
+ * sources never enable clustering, so created collections persist.
+ * VALIDATE-ALL-THEN-MUTATE-ALL: every field/type check runs before the first
+ * assignment, so a failure anywhere leaves BOTH collections on Cesium's
+ * default blend — the fallback this helper promises.
+ * @param {Cesium.DataSource|null|undefined} dataSource
+ * @returns {{applied:number,pending:number,invariantFailed:boolean}}
+ */
+
+export function applyTranslucentMarkerBlend(dataSource) {
+  const probe = probeTranslucentMarkerBlend(dataSource);
+  if (probe.invariantFailed)
+    return { applied: 0, pending: 0, invariantFailed: true };
+  return commitTranslucentMarkerBlend(probe);
+}