Merge pull request #1518 from manjunath22466/manjunath/hal-769-range-ring-visibility

fix(awareness): make the 250 km range ring readable on any ground

changelog.d/1518-range-ring-visibility.md

@@ -0,0 +1,4 @@
+- Draw the Global Context 250 km range ring as a 4 px line with a dark halo,
+  so it stays visible over desert, snow, ocean and forest and under the FLIR,
+  NVG and CRT styles, where the old 1 px outline disappeared (manjunath22466,
+  #1518).

docs/CURRENT-STATE.md

@@ -4997,6 +4997,7 @@ silently demoting every later lookup for the session.
 - Enabled Data Layer controls report normalized feed health on the button (`LOADING`, `DEGRADED`, `STALE`, `FALLBACK`, or `UNAVAILABLE`) while the metadata line retains the source and reason. A partial CelesTrak group failure keeps the usable catalog and reports `DEGRADED`; a total outage keeps last-good catalog data visible but reports `UNAVAILABLE`.
 - On activation it focuses the nearest currently observed aircraft across the civilian and military feeds, with military winning an exact distance tie; if none are available, it focuses an observed AIS vessel. The aircraft search is deliberately uncapped and one refresh-tick retry handles initially empty feeds. This is an attention-priority navigation shortcut, not a high-risk, affiliation, or threat classification.
 - A selected aircraft, AIS vessel, or mapped installation gets a 250 km **context window** with nearby cohort counts, nearest examples, source labels, and stale/unavailable reasons. It emits `NEARBY` or `UNKNOWN`; no detection, engagement, affiliation, or sensor-activity conclusion is calculated.
+- The window's edge is drawn on the globe as a 250 km range ring: a 4 px polyline with a 2 px Context-blue core inside a 1 px dark halo on each side, 2.5 km above the ellipsoid (`AWARENESS_RANGE_RING_STYLE` in `src/layers/awareness/policy.js`). The halo keeps it legible over bright desert and snow, dark ocean and forest, and under the FLIR, NVG and CRT styles, where the earlier 1 px ellipse outline disappeared. It is a polyline because WebGL draws ellipse outlines at 1 px whatever width is asked for. The ring follows a moving subject once it has moved 250 m.
 - For a selected live aircraft or vessel, the context window refreshes from the existing tracker/feed position every 750 ms, so nearest distances and cohort counts follow the subject without introducing a duplicate poll loop.
 - Aircraft cohort membership uses every locally loaded, selectable contact inside the 250 km window, including a plane hidden only by horizon culling or because its 3D model owns the visual. Counts and navigation therefore do not change with the current camera angle or billboard/model handoff.
 - Nearby examples in the context panel are focus controls: they use their owning layer's existing selection/tracking path, then frame that contact. Static-installation distances use ellipsoidal surface distance so the count matches the ground-projected context disk.

scripts/format-scope.json

@@ -1223,5 +1223,6 @@
   "src/voice/areaActions.test.mjs",
   "src/voice/imageryActions.test.mjs",
   "src/voice/osmActions.test.mjs",
-  "src/voice/realtimeProtocol.test.mjs"
+  "src/voice/realtimeProtocol.test.mjs",
+  "src/layers/awareness/rangeRing.test.mjs"
 ]

src/layers/awareness/policy.js

@@ -44,6 +44,20 @@ export const AWARENESS_MAX_NAVIGATION_EXAMPLES = 10000;
 
 export const CONTEXT_RIM_HEIGHT_M = 2500;
 
+/** @constant The 250 km range ring around the Global Context subject.
+ *  The old 1 px ellipse outline vanished over desert, snow and under
+ *  the FLIR, NVG and CRT styles. A bright core inside a dark halo keeps
+ *  luminance contrast on light and dark ground alike, and luminance is what
+ *  the monochrome styles keep. The core is the Context panel's blue; the halo
+ *  is the map-card ink. Widths are screen pixels; `outlineWidth` is per side. */
+export const AWARENESS_RANGE_RING_STYLE = Object.freeze({
+  color: 'rgba(98, 181, 255, 0.95)',
+  outlineColor: 'rgba(4, 12, 16, 0.8)',
+  width: 4,
+  outlineWidth: 1,
+  segments: 128,
+});
+
 export const VESSEL_FOCUS_RADIUS_M = 3000;
 
 export const SOURCE_LABEL = {

src/layers/awareness/rangeRing.test.mjs

@@ -0,0 +1,204 @@
+// src/layers/awareness/rangeRing.test.mjs — the 250 km Global Context range
+// ring is a haloed polyline that stays legible on light and dark ground,
+// sits where the old ellipse outline did, and follows the subject.
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import * as Cesium from 'cesium';
+import { AWARENESS_RADIUS_M } from '../../data/militaryAwarenessEngine.js';
+import { AWARENESS_RANGE_RING_STYLE, CONTEXT_RIM_HEIGHT_M } from './policy.js';
+import { awarenessRangeRingPositions, createRendering } from './rendering.js';
+import { createState } from './state.js';
+
+/** WCAG relative luminance of a Cesium colour, ignoring alpha. */
+function luminance(color) {
+  const channel = (c) =>
+    c <= 0.03928 ? c / 12.92 : ((c + 0.055) / 1.055) ** 2.4;
+  return (
+    0.2126 * channel(color.red) +
+    0.7152 * channel(color.green) +
+    0.0722 * channel(color.blue)
+  );
+}
+
+/** The rendering part over a bare entity collection, counting render asks. */
+function ringRendering() {
+  const state = createState({ services: {} });
+  const entities = new Cesium.EntityCollection();
+  state.viewer = { entities };
+  let renders = 0;
+  const rendering = createRendering({
+    state,
+    services: {
+      geometry: {},
+      render: {
+        governorRequestRender() {
+          renders += 1;
+        },
+      },
+    },
+    parts: {},
+  });
+  return { entities, rendering, renders: () => renders };
+}
+
+/** Surface distance from `center` to each ring position. */
+function surfaceDistances(center, positions) {
+  const from = Cesium.Cartographic.fromCartesian(center);
+  return positions.map((position) => {
+    const to = Cesium.Cartographic.fromCartesian(position);
+    return new Cesium.EllipsoidGeodesic(from, to).surfaceDistance;
+  });
+}
+
+for (const [place, lat, lon] of [
+  ['equator', 0, 0],
+  ['Sahara', 27, 3],
+  ['Greenland', 72, -40],
+  ['antimeridian', 10, 179.9],
+]) {
+  test(`ring positions stay 250 km from the subject at ${place}`, () => {
+    const center = Cesium.Cartesian3.fromDegrees(lon, lat, 0);
+    const positions = awarenessRangeRingPositions(
+      center,
+      AWARENESS_RADIUS_M,
+      CONTEXT_RIM_HEIGHT_M,
+    );
+    assert.equal(positions.length, AWARENESS_RANGE_RING_STYLE.segments + 1);
+    assert.ok(
+      Cesium.Cartesian3.equalsEpsilon(positions[0], positions.at(-1), 0, 1e-6),
+      'the ring closes on itself',
+    );
+    // Within 100 m of 250 km on the WGS84 ellipsoid.
+    for (const distance of surfaceDistances(center, positions))
+      assert.ok(Math.abs(distance - AWARENESS_RADIUS_M) < 100, `${distance} m`);
+    for (const position of positions)
+      assert.ok(
+        Math.abs(
+          Cesium.Cartographic.fromCartesian(position).height -
+            CONTEXT_RIM_HEIGHT_M,
+        ) < 1e-3,
+      );
+  });
+}
+
+for (const [place, lat, lon] of [
+  ['the North Pole', 90, 0],
+  ['the South Pole', -90, 0],
+  ['1e-7° from the North Pole', 90 - 1e-7, 45],
+  ['1e-8° from the South Pole', -90 + 1e-8, -120],
+]) {
+  test(`the ring stays a full circle at ${place}`, () => {
+    const center = Cesium.Cartesian3.fromDegrees(lon, lat, 0);
+    const segments = AWARENESS_RANGE_RING_STYLE.segments;
+    const positions = awarenessRangeRingPositions(
+      center,
+      AWARENESS_RADIUS_M,
+      CONTEXT_RIM_HEIGHT_M,
+    );
+    assert.equal(positions.length, segments + 1);
+    assert.ok(
+      Cesium.Cartesian3.equalsEpsilon(positions[0], positions.at(-1), 0, 1e-6),
+      'the ring closes on itself',
+    );
+    const distinct = new Set(
+      positions
+        .slice(0, segments)
+        .map(({ x, y, z }) => [x, y, z].map((v) => v.toFixed(1)).join()),
+    );
+    assert.equal(distinct.size, segments, 'every vertex is its own point');
+    // Ordinary chords are 2π × 250 km / 128 ≈ 12.3 km long.
+    for (let i = 0; i < segments; i++) {
+      const chord = Cesium.Cartesian3.distance(positions[i], positions[i + 1]);
+      assert.ok(chord > 11_500 && chord < 13_000, `chord ${i}: ${chord} m`);
+    }
+    for (const distance of surfaceDistances(center, positions))
+      assert.ok(Math.abs(distance - AWARENESS_RADIUS_M) < 100, `${distance} m`);
+  });
+}
+
+test('the ring core and halo contrast on light and dark ground', () => {
+  const core = Cesium.Color.fromCssColorString(
+    AWARENESS_RANGE_RING_STYLE.color,
+  );
+  const halo = Cesium.Color.fromCssColorString(
+    AWARENESS_RANGE_RING_STYLE.outlineColor,
+  );
+  // Core against halo is the edge that survives bright desert and snow, and
+  // the monochrome styles that map everything to luminance.
+  const ratio = (luminance(core) + 0.05) / (luminance(halo) + 0.05);
+  assert.ok(ratio >= 4.5, `core:halo contrast ${ratio.toFixed(2)}`);
+  assert.ok(core.alpha >= 0.9 && halo.alpha >= 0.7);
+  // A visible halo on each side of a core at least 2 px wide.
+  const { width, outlineWidth } = AWARENESS_RANGE_RING_STYLE;
+  assert.ok(outlineWidth >= 1);
+  assert.ok(width - 2 * outlineWidth >= 2);
+});
+
+test('renderVisual draws one haloed polyline ring, not an ellipse outline', () => {
+  const { entities, rendering } = ringRendering();
+  const subject = {
+    layerId: 'flights',
+    id: 'abc123',
+    position: Cesium.Cartesian3.fromDegrees(3, 27, 9000),
+  };
+  rendering.renderVisual(subject);
+  assert.equal(entities.values.length, 1);
+  const [entity] = entities.values;
+  assert.equal(entity.ellipse, undefined);
+  const now = Cesium.JulianDate.now();
+  assert.equal(entity.polyline.width.getValue(now), 4);
+  assert.equal(entity.polyline.arcType.getValue(now), Cesium.ArcType.NONE);
+  const material = entity.polyline.material;
+  assert.ok(material instanceof Cesium.PolylineOutlineMaterialProperty);
+  assert.equal(
+    material.color.getValue(now).toCssColorString(),
+    Cesium.Color.fromCssColorString(
+      AWARENESS_RANGE_RING_STYLE.color,
+    ).toCssColorString(),
+  );
+  assert.equal(
+    material.outlineWidth.getValue(now),
+    AWARENESS_RANGE_RING_STYLE.outlineWidth,
+  );
+  const ground = Cesium.Cartesian3.fromDegrees(3, 27, 0);
+  for (const distance of surfaceDistances(
+    ground,
+    entity.polyline.positions.getValue(now),
+  ))
+    assert.ok(Math.abs(distance - AWARENESS_RADIUS_M) < 100);
+});
+
+test('the ring follows the subject past 250 m and ignores smaller drift', () => {
+  const { entities, rendering, renders } = ringRendering();
+  const subject = (lon) => ({
+    layerId: 'flights',
+    id: 'abc123',
+    position: Cesium.Cartesian3.fromDegrees(lon, 27, 9000),
+  });
+  rendering.renderVisual(subject(3));
+  const [entity] = entities.values;
+  const now = Cesium.JulianDate.now();
+  const first = entity.polyline.positions.getValue(now);
+  const rendersAfterAdd = renders();
+
+  // ~100 m east: under the threshold, nothing is rebuilt or rendered.
+  rendering.renderVisual(subject(3.001));
+  assert.equal(entity.polyline.positions.getValue(now), first);
+  assert.equal(renders(), rendersAfterAdd);
+
+  // ~1 km east: the same entity moves to the new centre.
+  rendering.renderVisual(subject(3.01));
+  assert.equal(entities.values.length, 1);
+  assert.equal(entities.values[0], entity);
+  const moved = entity.polyline.positions.getValue(now);
+  assert.notEqual(moved, first);
+  for (const distance of surfaceDistances(
+    Cesium.Cartesian3.fromDegrees(3.01, 27, 0),
+    moved,
+  ))
+    assert.ok(Math.abs(distance - AWARENESS_RADIUS_M) < 100);
+  assert.equal(renders(), rendersAfterAdd + 1);
+
+  rendering.clearVisual();
+  assert.equal(entities.values.length, 0);
+});

src/layers/awareness/rendering.js

@@ -10,9 +10,66 @@ import {
   AWARENESS_RADIUS_M,
 } from '../../data/militaryAwarenessEngine.js';
 import { bearingBetweenCoordinates } from '../../cockpitMath.js';
-import { AWARENESS_PAGE_SIZE, CONTEXT_RIM_HEIGHT_M } from './policy.js';
+import {
+  AWARENESS_PAGE_SIZE,
+  AWARENESS_RANGE_RING_STYLE,
+  CONTEXT_RIM_HEIGHT_M,
+} from './policy.js';
 import { formatAwarenessDirection } from './presentation.js';
 
+/**
+ * A closed ring of positions `radiusM` along the surface from `groundCenter`,
+ * raised to `heightM`. Each bearing steps over a sphere with the ellipsoid's
+ * radius of curvature in that direction (Euler's formula), which keeps the
+ * ring within ~50 m of the true geodesic radius at 250 km.
+ * @param {Cesium.Cartesian3} groundCenter Ring centre on the ellipsoid.
+ * @param {number} radiusM Surface radius in metres.
+ * @param {number} heightM Height of the ring above the ellipsoid.
+ * @param {number} [segments] Chords around the ring.
+ * @returns {Cesium.Cartesian3[]} `segments + 1` positions; the last repeats the first.
+ */
+export function awarenessRangeRingPositions(
+  groundCenter,
+  radiusM,
+  heightM,
+  segments = AWARENESS_RANGE_RING_STYLE.segments,
+) {
+  const { latitude, longitude } =
+    Cesium.Cartographic.fromCartesian(groundCenter);
+  const { x: a, z: b } = Cesium.Ellipsoid.WGS84.radii;
+  const e2 = 1 - (b * b) / (a * a);
+  const sinLat = Math.sin(latitude);
+  const cosLat = Math.cos(latitude);
+  const sinLon = Math.sin(longitude);
+  const cosLon = Math.cos(longitude);
+  const w = 1 - e2 * sinLat * sinLat;
+  const meridional = (a * (1 - e2)) / (w * Math.sqrt(w));
+  const primeVertical = a / Math.sqrt(w);
+  // Step along the great circle in 3D from the centre's up, north and east
+  // unit vectors. Unlike the latitude/longitude destination formula, this
+  // stays well conditioned at and next to the poles.
+  const up = [cosLat * cosLon, cosLat * sinLon, sinLat];
+  const north = [-sinLat * cosLon, -sinLat * sinLon, cosLat];
+  const east = [-sinLon, cosLon, 0];
+  const positions = [];
+  for (let i = 0; i <= segments; i++) {
+    const bearing = ((i % segments) / segments) * Cesium.Math.TWO_PI;
+    const cosB = Math.cos(bearing);
+    const sinB = Math.sin(bearing);
+    const angular =
+      radiusM * ((cosB * cosB) / meridional + (sinB * sinB) / primeVertical);
+    const cosA = Math.cos(angular);
+    const sinA = Math.sin(angular);
+    const [x, y, z] = up.map(
+      (u, k) => u * cosA + (north[k] * cosB + east[k] * sinB) * sinA,
+    );
+    const lat = Math.atan2(z, Math.hypot(x, y));
+    const lon = Math.atan2(y, x);
+    positions.push(Cesium.Cartesian3.fromRadians(lon, lat, heightM));
+  }
+  return positions;
+}
+
 export function createRendering({
   state: layerState,
   services,
@@ -292,15 +349,19 @@ export function createRendering({
     );
     const key = `${subject.layerId}:${subject.id}`;
     if (layerState.visual?.key === key) {
-      // Large ellipse geometry is more reliable as a ConstantPositionProperty.
+      // Move the ring only after a meaningful displacement so live tracking
-      // Move it only after a meaningful displacement so live tracking does not
+      // does not rebuild its geometry for sub-pixel motion every 750 ms.
-      // churn ten large geometries for sub-pixel motion every 750 ms.
       if (
         Cesium.Cartesian3.distance(layerState.visual.center, groundCenter) >=
         250
       ) {
+        const positions = awarenessRangeRingPositions(
+          groundCenter,
+          AWARENESS_RADIUS_M,
+          CONTEXT_RIM_HEIGHT_M,
+        );
         for (const entity of layerState.visual.entities)
-          entity.position.setValue(groundCenter);
+          entity.polyline.positions.setValue(positions);
         Cesium.Cartesian3.clone(groundCenter, layerState.visual.center);
         // Content actually changed — buy exactly one frame instead of holding.
         governorRequestRender('awareness-visual');
@@ -311,17 +372,26 @@ export function createRendering({
 
     const entities = [];
 
+    // A polyline, not an ellipse outline: WebGL draws ellipse outlines at
+    // 1 px whatever `outlineWidth` says, and the ring needs a halo.
+    const ring = AWARENESS_RANGE_RING_STYLE;
     entities.push(
       layerState.viewer.entities.add({
-        position: groundCenter,
+        polyline: {
-        ellipse: {
+          positions: new Cesium.ConstantProperty(
-          semiMajorAxis: AWARENESS_RADIUS_M,
+            awarenessRangeRingPositions(
-          semiMinorAxis: AWARENESS_RADIUS_M,
+              groundCenter,
-          fill: false,
+              AWARENESS_RADIUS_M,
-          outline: true,
+              CONTEXT_RIM_HEIGHT_M,
-          outlineColor:
+            ),
-            Cesium.Color.fromCssColorString('#62b5ff').withAlpha(0.72),
+          ),
-          height: CONTEXT_RIM_HEIGHT_M,
+          width: ring.width,
+          arcType: Cesium.ArcType.NONE,
+          material: new Cesium.PolylineOutlineMaterialProperty({
+            color: Cesium.Color.fromCssColorString(ring.color),
+            outlineColor: Cesium.Color.fromCssColorString(ring.outlineColor),
+            outlineWidth: ring.outlineWidth,
+          }),
         },
       }),
     );