feat(awareness): render the Global Context compass from a store

The awareness layer presents the compass ring, heading, cardinal labels and
contact bearing markers through subscribeDirectionOverlay(); the application
shell publishes them to the gev-awareness-direction store and the scene
chrome renders them in the viewer's container.

src/layers/awareness/directionOverlay.test.mjs

@@ -0,0 +1,185 @@
+// src/layers/awareness/directionOverlay.test.mjs — the Global Context compass
+// and contact bearings are presented to subscribers and rendered from a store
+// inside the viewer's container.
+import '../../testSupport/registerDom.mjs';
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import * as Cesium from 'cesium';
+import { createApp, nextTick } from 'vue';
+import { createPinia } from 'pinia';
+import { useAwarenessDirectionStore } from '../../ui/stores/awarenessDirection.js';
+import AwarenessDirection from '../../ui/views/panels/AwarenessDirection.vue';
+import { createState } from './state.js';
+import { createRendering } from './rendering.js';
+
+/** The rendering part over a subject with one military contact due east. */
+function overlay(screenAngle) {
+  const state = createState({ services: {} });
+  const container = document.body.appendChild(document.createElement('div'));
+  const subject = Cesium.Cartesian3.fromDegrees(0, 0, 1000);
+  Object.assign(state, {
+    viewer: {
+      container,
+      scene: { canvas: { clientWidth: 800, clientHeight: 600 } },
+      camera: {
+        heading: 0,
+        rightWC: new Cesium.Cartesian3(0, 1, 0),
+        upWC: new Cesium.Cartesian3(0, 0, 1),
+      },
+    },
+    enabled: true,
+    subject: { position: subject, layerId: 'military' },
+    results: {
+      cohorts: [
+        {
+          id: 'military',
+          summary: {
+            nearest: [
+              {
+                callsign: 'RCH123',
+                position: Cesium.Cartesian3.fromDegrees(0.05, 0, 1000),
+                distanceM: 5500,
+                track: 90,
+              },
+            ],
+          },
+        },
+      ],
+    },
+    cohortPages: new Map(),
+  });
+  const rendering = createRendering({
+    state,
+    services: {
+      geometry: {
+        getKeyholeGeometry: () => ({ centerX: 400, centerY: 300, radius: 250 }),
+        celestialScreenAngle:
+          screenAngle ||
+          ((x, y) => ({
+            angle: Math.atan2(-y, x),
+            opacity: 1,
+            stable: true,
+          })),
+      },
+      render: { governorRequestRender() {} },
+    },
+    parts: {},
+  });
+  return { state, container, rendering };
+}
+
+test('the overlay publishes the compass and the nearest contact bearings', () => {
+  const { rendering, container } = overlay();
+  const views = [];
+  rendering.subscribeDirectionOverlay((view) => views.push(view));
+  assert.deepEqual(views, [null]);
+  rendering.updateDirectionOverlay();
+  const view = views.at(-1);
+  assert.ok(view.container === container);
+  assert.equal(view.hidden, false);
+  // The compass sits at 66% of the 250px keyhole: 165px.
+  assert.equal(view.ring.width, '330px');
+  assert.equal(view.ring['--compass-rotation'], '0deg');
+  assert.equal(view.heading.text, 'HDG 000°');
+  assert.deepEqual(
+    view.labels.map((label) => label.label),
+    ['N', 'E', 'S', 'W'],
+  );
+  assert.equal(view.labels[0].left, '400px');
+  const [marker, second] = view.markers;
+  assert.equal(marker.hidden, false);
+  assert.match(marker.caption.text, /^RCH123 · .+\nBRG 090° · CRS 090°$/);
+  assert.equal(marker.arrow.opacity, '1');
+  assert.equal(second.hidden, true);
+  // An unchanged frame publishes nothing.
+  const count = views.length;
+  rendering.updateDirectionOverlay();
+  assert.equal(views.length, count);
+  rendering.hideDirectionOverlay();
+  assert.equal(views.at(-1).hidden, true);
+  assert.equal(views.at(-1).heading.text, 'HDG 000°', 'placement is kept');
+  rendering.removeDirectionOverlay();
+  assert.equal(views.at(-1), null);
+});
+
+test('an unstable frame keeps the last stable bearing, until the overlay is removed', () => {
+  const answers = [
+    { angle: 1, opacity: 1, stable: true },
+    { angle: 2, opacity: 0.5, stable: false },
+  ];
+  const previous = [];
+  const { state, rendering } = overlay((x, y, last) => {
+    previous.push(last);
+    return answers.shift() ?? { angle: last ?? 0, opacity: 1, stable: true };
+  });
+  rendering.updateDirectionOverlay();
+  assert.equal(state.directionAngles[0], 1);
+  // The heading turns, so the next frame recomputes the contact.
+  state.viewer.camera.heading = 0.1;
+  rendering.updateDirectionOverlay();
+  assert.equal(previous[1], 1, 'the unstable frame is given the last angle');
+  assert.equal(state.directionAngles[0], 1, 'and does not replace it');
+  rendering.removeDirectionOverlay();
+  rendering.updateDirectionOverlay();
+  assert.equal(previous[2], 0, 'a rebuilt overlay starts afresh');
+});
+
+test('the scene chrome view renders the published overlay in its container', async (t) => {
+  document.body.replaceChildren();
+  const pinia = createPinia();
+  const store = useAwarenessDirectionStore(pinia);
+  const app = createApp(AwarenessDirection).use(pinia);
+  app.mount(document.body.appendChild(document.createElement('div')));
+  t.after(() => app.unmount());
+  const { rendering, container } = overlay();
+  rendering.subscribeDirectionOverlay((view) => store.publish(view));
+  rendering.ensureDirectionOverlay();
+  await nextTick();
+  const root = container.querySelector('#military-awareness-direction-overlay');
+  assert.equal(root.hidden, true);
+  assert.equal(root.getAttribute('aria-hidden'), 'true');
+  assert.deepEqual(
+    [...root.children].map((child) => child.className),
+    [
+      'military-awareness-compass-label cardinal-n',
+      'military-awareness-compass-label cardinal-e',
+      'military-awareness-compass-label cardinal-s',
+      'military-awareness-compass-label cardinal-w',
+      'military-awareness-compass-ring',
+      'military-awareness-compass-heading',
+      'military-awareness-direction-marker',
+      'military-awareness-direction-marker',
+      'military-awareness-direction-marker',
+    ],
+  );
+  assert.equal(root.children[0].dataset.bearing, '0');
+  assert.equal(root.children[0].getAttribute('style'), null);
+  rendering.updateDirectionOverlay();
+  await nextTick();
+  assert.equal(root.hidden, false);
+  const ring = root.querySelector('.military-awareness-compass-ring');
+  assert.equal(ring.style.getPropertyValue('--compass-rotation'), '0deg');
+  assert.equal(
+    root.querySelector('.military-awareness-compass-heading').textContent,
+    'HDG 000°',
+  );
+  const [marker, second] = root.querySelectorAll(
+    '.military-awareness-direction-marker',
+  );
+  assert.equal(marker.hidden, false);
+  assert.equal(
+    marker.querySelector('.military-awareness-direction-arrow').textContent,
+    '➜',
+  );
+  assert.match(
+    marker.querySelector('.military-awareness-direction-label').textContent,
+    /^RCH123 · /,
+  );
+  assert.equal(second.hidden, true);
+  rendering.removeDirectionOverlay();
+  await nextTick();
+  assert.equal(
+    container.querySelector('#military-awareness-direction-overlay'),
+    null,
+  );
+});

src/layers/awareness/index.js

@@ -57,6 +57,7 @@ export function createAwarenessLayer({ services, source }) {
       historySubjectSnapshot: parts.history.historySubjectSnapshot,
       findCompatibleHistoryIndex: parts.history.findCompatibleHistoryIndex,
       subscribePanel: parts.panel.subscribePanel,
+      subscribeDirectionOverlay: parts.rendering.subscribeDirectionOverlay,
       awarenessResultsAreLive: parts.panel.awarenessResultsAreLive,
       awarenessNeedsContinuousRender:
         parts.model.awarenessNeedsContinuousRender,

src/layers/awareness/lifecycle.js

@@ -230,12 +230,7 @@ export function createLifecycle({
       this.disable();
       detachRuntimeListeners();
       parts.panel.clearPanel();
-      layerState.directionRoot?.remove();
-      layerState.directionRoot = null;
-      layerState.compassRing = null;
-      layerState.compassLabels = [];
-      layerState.compassHeading = null;
-      layerState.directionMarkers = [];
+      parts.rendering.removeDirectionOverlay();
       layerState.subjectListener = null;
       layerState.contextListener = null;
       layerState.clearListener = null;

src/layers/awareness/panel.js

@@ -86,7 +86,7 @@ export function createPanel({ state: layerState, parts }) {
           ? t('SELECT A FLIGHT, VESSEL, OR MAPPED INSTALLATION')
           : t('ENABLE TO LOAD OBSERVED / MAPPED PROXIMITY'),
       });
-    if (layerState.directionRoot) layerState.directionRoot.hidden = true;
+    parts.rendering.hideDirectionOverlay();
   }
 
   /** Clear the panel when the layer is destroyed. */

src/layers/awareness/rendering.js

@@ -22,55 +22,75 @@ export function createRendering({
   const { getKeyholeGeometry, celestialScreenAngle } = services.geometry;
   const { governorRequestRender } = services.render;
 
+  const CARDINALS = [
+    ['N', 0],
+    ['E', 90],
+    ['S', 180],
+    ['W', 270],
+  ];
+
+  /**
+   * The direction overlay as its view renders it: the compass ring, its
+   * cardinals and heading, and up to three contact markers inside the
+   * viewer's container. Each part keeps its last placement while hidden.
+   */
   function ensureDirectionOverlay() {
-    if (layerState.directionRoot || !layerState.viewer)
-      return layerState.directionRoot;
-    const root = document.createElement('div');
-    root.id = 'military-awareness-direction-overlay';
-    root.hidden = true;
-    root.setAttribute('aria-hidden', 'true');
-
-    const compass = document.createElement('div');
-    compass.className = 'military-awareness-compass-ring';
-    const cardinals = [
-      ['N', 0],
-      ['E', 90],
-      ['S', 180],
-      ['W', 270],
-    ];
-    layerState.compassLabels = cardinals.map(([label, bearing]) => {
-      const element = document.createElement('span');
-      element.className = `military-awareness-compass-label cardinal-${label.toLowerCase()}`;
-      element.textContent = label;
-      element.dataset.bearing = String(bearing);
-      root.appendChild(element);
-      return element;
+    if (layerState.directionView || !layerState.viewer)
+      return layerState.directionView;
+    presentDirection({
+      container: layerState.viewer.container,
+      hidden: true,
+      ring: null,
+      heading: { text: '', left: null, top: null },
+      labels: CARDINALS.map(([label, bearing]) => ({
+        label,
+        bearing,
+        left: null,
+        top: null,
+      })),
+      markers: Array.from({ length: 3 }, () => ({
+        hidden: false,
+        style: null,
+        arrow: null,
+        caption: { text: '', style: null },
+      })),
     });
-    const heading = document.createElement('span');
-    heading.className = 'military-awareness-compass-heading';
-    root.append(compass, heading);
+    return layerState.directionView;
+  }
 
-    layerState.directionMarkers = Array.from({ length: 3 }, () => {
-      const marker = document.createElement('div');
-      marker.className = 'military-awareness-direction-marker';
-      const arrow = document.createElement('span');
-      arrow.className = 'military-awareness-direction-arrow';
-      arrow.textContent = '➜';
-      const label = document.createElement('span');
-      label.className = 'military-awareness-direction-label';
-      marker.append(arrow, label);
-      marker._arrow = arrow;
-      marker._label = label;
-      marker._lastAngle = 0;
-      root.appendChild(marker);
-      return marker;
-    });
+  /** Publish a change to the overlay, skipping one that changes nothing. */
+  function presentDirection(patch) {
+    const next = patch && { ...layerState.directionView, ...patch };
+    const signature = JSON.stringify(next, (name, value) =>
+      name === 'container' ? undefined : value,
+    );
+    if (next && signature === layerState.directionSignature) return;
+    layerState.directionSignature = next ? signature : '';
+    layerState.directionView = next && Object.freeze(next);
+    for (const listener of [...layerState.directionListeners])
+      listener(layerState.directionView);
+  }
 
-    layerState.compassRing = compass;
-    layerState.compassHeading = heading;
-    layerState.viewer.container.appendChild(root);
-    layerState.directionRoot = root;
-    return root;
+  /**
+   * Receive the direction overlay now and after every change.
+   * @param {(view: ?object) => void} listener
+   * @returns {() => void} Unsubscribe.
+   */
+  function subscribeDirectionOverlay(listener) {
+    layerState.directionListeners.add(listener);
+    listener(layerState.directionView);
+    return () => layerState.directionListeners.delete(listener);
+  }
+
+  /** Hide the overlay, keeping its last placement. */
+  function hideDirectionOverlay() {
+    if (layerState.directionView) presentDirection({ hidden: true });
+  }
+
+  /** Withdraw the overlay when the layer is destroyed. */
+  function removeDirectionOverlay() {
+    if (layerState.directionView) presentDirection(null);
+    layerState.directionAngles = [0, 0, 0];
   }
 
   function scheduleDirectionOverlayUpdate(force = false) {
@@ -104,7 +124,7 @@ export function createRendering({
       !layerState.subject?.position ||
       !layerState.results
     ) {
-      if (root) root.hidden = true;
+      if (root) presentDirection({ hidden: true });
       return;
     }
 
@@ -116,41 +136,43 @@ export function createRendering({
       : null;
     const geometry = getKeyholeGeometry(width, height);
     if (!(geometry.radius > 0)) {
-      root.hidden = true;
+      presentDirection({ hidden: true });
       return;
     }
 
-    root.hidden = false;
     // Keep the compass comfortably inside the shader keyhole so its cardinals
     // remain visible around the subject instead of hiding under edge panels.
     const compassRadius = Math.max(
       120,
       Math.min(geometry.radius - 48, geometry.radius * 0.66),
     );
-    layerState.compassRing.style.left = `${geometry.centerX - compassRadius}px`;
-    layerState.compassRing.style.top = `${geometry.centerY - compassRadius}px`;
-    layerState.compassRing.style.width = `${compassRadius * 2}px`;
-    layerState.compassRing.style.height = `${compassRadius * 2}px`;
-
     const cameraHeading = layerState.viewer.camera.heading || 0;
     const headingDeg =
       (Math.round(Cesium.Math.toDegrees(cameraHeading)) + 360) % 360;
-    layerState.compassRing.style.setProperty(
-      '--compass-rotation',
-      `${-headingDeg}deg`,
-    );
-    layerState.compassHeading.textContent = t('HDG {value}°', {
-      value: String(headingDeg).padStart(3, '0'),
-    });
-    layerState.compassHeading.style.left = `${geometry.centerX}px`;
-    layerState.compassHeading.style.top = `${geometry.centerY - compassRadius + 39}px`;
-    for (const label of layerState.compassLabels) {
-      const bearing = Cesium.Math.toRadians(Number(label.dataset.bearing));
+    const ring = {
+      left: `${geometry.centerX - compassRadius}px`,
+      top: `${geometry.centerY - compassRadius}px`,
+      width: `${compassRadius * 2}px`,
+      height: `${compassRadius * 2}px`,
+      '--compass-rotation': `${-headingDeg}deg`,
+    };
+    const heading = {
+      text: t('HDG {value}°', {
+        value: String(headingDeg).padStart(3, '0'),
+      }),
+      left: `${geometry.centerX}px`,
+      top: `${geometry.centerY - compassRadius + 39}px`,
+    };
+    const labels = root.labels.map((label) => {
+      const bearing = Cesium.Math.toRadians(label.bearing);
       const angle = bearing - cameraHeading - Cesium.Math.PI_OVER_TWO;
       const labelRadius = compassRadius - 17;
-      label.style.left = `${geometry.centerX + Math.cos(angle) * labelRadius}px`;
-      label.style.top = `${geometry.centerY + Math.sin(angle) * labelRadius}px`;
-    }
+      return {
+        ...label,
+        left: `${geometry.centerX + Math.cos(angle) * labelRadius}px`,
+        top: `${geometry.centerY + Math.sin(angle) * labelRadius}px`,
+      };
+    });
 
     const directionalCohort =
       layerState.results.cohorts.find(
@@ -163,8 +185,9 @@ export function createRendering({
         page,
         page + AWARENESS_PAGE_SIZE,
       ) || [];
-    for (let index = 0; index < layerState.directionMarkers.length; index++) {
-      const marker = layerState.directionMarkers[index];
+    const markers = root.markers.map((marker) => ({ ...marker }));
+    for (let index = 0; index < markers.length; index++) {
+      const marker = markers[index];
       const item = military[index];
       if (!item?.position) {
         marker.hidden = true;
@@ -183,27 +206,32 @@ export function createRendering({
       const projection = celestialScreenAngle(
         Cesium.Cartesian3.dot(direction, layerState.viewer.camera.rightWC),
         Cesium.Cartesian3.dot(direction, layerState.viewer.camera.upWC),
-        marker._lastAngle,
+        layerState.directionAngles[index],
       );
-      if (projection.stable) marker._lastAngle = projection.angle;
+      if (projection.stable)
+        layerState.directionAngles[index] = projection.angle;
       // Every detected contact shares the compass rim. Keeping the bearing
       // markers on one radius makes them read as compass contacts rather than
       // unconstrained labels floating over the map.
       const markerRadius = compassRadius;
-      marker.style.left = `${geometry.centerX + Math.cos(projection.angle) * markerRadius}px`;
-      marker.style.top = `${geometry.centerY + Math.sin(projection.angle) * markerRadius}px`;
-      marker.style.opacity = String(projection.opacity);
+      marker.style = {
+        left: `${geometry.centerX + Math.cos(projection.angle) * markerRadius}px`,
+        top: `${geometry.centerY + Math.sin(projection.angle) * markerRadius}px`,
+        opacity: String(projection.opacity),
+      };
       const sonarFactor =
         sonar?.at(
           geometry.centerX + Math.cos(projection.angle) * markerRadius,
           geometry.centerY + Math.sin(projection.angle) * markerRadius,
         ) ?? 1;
-      marker._arrow.style.opacity = String(sonarFactor);
-      marker._label.style.opacity = String(
-        sonar ? sonar.label(sonarFactor) : 1,
-      );
-      marker._arrow.style.transform = `translate(-50%, -50%) rotate(${projection.angle}rad)`;
-      marker._label.style.transform = `translate(-50%, -50%) translate(${-Math.cos(projection.angle) * 56}px, ${-Math.sin(projection.angle) * 56}px)`;
+      marker.arrow = {
+        opacity: String(sonarFactor),
+        transform: `translate(-50%, -50%) rotate(${projection.angle}rad)`,
+      };
+      const labelStyle = {
+        opacity: String(sonar ? sonar.label(sonarFactor) : 1),
+        transform: `translate(-50%, -50%) translate(${-Math.cos(projection.angle) * 56}px, ${-Math.sin(projection.angle) * 56}px)`,
+      };
       const label = formatAwarenessLabel(item);
       const subjectCartographic = Cesium.Cartographic.fromCartesian(
         layerState.subject.position,
@@ -234,9 +262,13 @@ export function createRendering({
             value: formatAwarenessDirection(item.track),
           })}`
         : '';
-      marker._label.textContent = `${label} · ${formatAwarenessDistance(item.distanceM)}\n${bearingText}${courseText}`;
+      marker.caption = {
+        text: `${label} · ${formatAwarenessDistance(item.distanceM)}\n${bearingText}${courseText}`,
+        style: labelStyle,
+      };
       marker.hidden = false;
     }
+    presentDirection({ hidden: false, ring, heading, labels, markers });
   }
 
   function clearVisual() {
@@ -303,6 +335,9 @@ export function createRendering({
   }
   return {
     ensureDirectionOverlay,
+    subscribeDirectionOverlay,
+    hideDirectionOverlay,
+    removeDirectionOverlay,
     scheduleDirectionOverlayUpdate,
     cancelDirectionOverlayUpdate,
     updateDirectionOverlay,

src/layers/awareness/state.js

@@ -43,11 +43,12 @@ export function createState({ services }) {
     subjectClearListener: null,
     runtimeListenersAttached: false,
     preRenderRemover: null,
-    directionRoot: null,
-    compassRing: null,
-    compassLabels: [],
-    compassHeading: null,
-    directionMarkers: [],
+    /** The published direction overlay, its signature and its subscribers. */
+    directionView: null,
+    directionSignature: '',
+    directionListeners: new Set(),
+    /** Each marker's last stable screen angle. */
+    directionAngles: [0, 0, 0],
     navigationHistory: [],
     navigationVisited: new Set(),
     navigationIndex: -1,