Merge pull request #1023 from rudycelekli/contrib/gods-002-director-dateline-seek-20261011-reviewed

fix(director): seek camera longitude across the shortest dateline arc

CHANGELOG.md

@@ -24,6 +24,8 @@
   the five borough cores load and `CCTV_NYC_MAX_SOURCES` changes the cap. The catalog-wide ceiling is
   unchanged; extra cameras share it round-robin with the other packs.
 
+- Director timeline seeks cross the dateline along the short longitude arc.
+
 - Treat explicitly current, complete empty vessel coverage as a successful update,
   clearing obsolete contacts while retaining stale or incomplete snapshots.
 

docs/CURRENT-STATE.md

@@ -399,6 +399,9 @@ camera moves with easing, duration and holds. Playback and seek share one
 coordinate sampler; navigation/manual input revokes authored motion and pending
 holds. Anchor heights and explicit endpoints require the WGS84 ellipsoid
 reference. Legacy projects retain their ordinary flights, content and edits.
+Seeking between ordinary camera poses uses the shortest longitude arc across the
+dateline while preserving both authored endpoint longitudes, and turns heading
+and roll the short way for any authored angles.
 See [camera directions](DIRECTOR-CAMERA.md).
 
 Realtime voice composes separate connection, response/tool, Radio handoff, input

src/director/camera.js

@@ -28,6 +28,11 @@ export function resolveCameraMove(scene, shot) {
   };
 }
 
+/** Wrap an interpolated camera longitude to WGS84 without changing authored endpoints. */
+export function normalizeCameraLongitude(longitude) {
+  return ((((longitude + 180) % 360) + 360) % 360) - 180;
+}
+
 /** Sample the same authored curve for playback and seeking, taking the short longitude/angle arc. */
 export function sampleCameraMove(move, progress) {
   const t = Math.max(0, Math.min(1, Number(progress) || 0));
@@ -45,7 +50,7 @@ export function sampleCameraMove(move, progress) {
   const { from, to } = move;
   return {
     lat: lerp(from.lat, to.lat),
-    lon: ((((angle(from.lon, to.lon) + 180) % 360) + 360) % 360) - 180,
+    lon: normalizeCameraLongitude(angle(from.lon, to.lon)),
     alt: lerp(from.alt, to.alt),
     heading: angle(from.heading, to.heading),
     pitch: lerp(from.pitch, to.pitch),

src/director/director-dateline-seek.test.mjs

@@ -0,0 +1,53 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { cameraAtProgress } from './timeline.js';
+const camera = (lon) => ({
+  lat: 10,
+  lon,
+  alt: 1000,
+  heading: 0,
+  pitch: -40,
+  roll: 0,
+});
+test('director seek follows the short dateline arc in both directions', () => {
+  for (const [a, b] of [
+    [179, -179],
+    [-179, 179],
+  ]) {
+    assert.equal(
+      Math.abs(cameraAtProgress(camera(a), camera(b), 0.5).lon),
+      180,
+    );
+    assert.equal(cameraAtProgress(camera(a), camera(b), 0).lon, a);
+    assert.equal(cameraAtProgress(camera(a), camera(b), 1).lon, b);
+    assert.ok(Math.abs(cameraAtProgress(camera(a), camera(b), 0.25).lon) > 179);
+  }
+  assert.equal(cameraAtProgress(camera(20), camera(24), 0.5).lon, 22);
+});
+
+test('director seek keeps exact ±180 endpoints and picks the short arc near the antipode', () => {
+  for (const [a, b] of [
+    [180, -180],
+    [-180, 180],
+  ]) {
+    assert.equal(cameraAtProgress(camera(a), camera(b), 0).lon, a);
+    assert.equal(cameraAtProgress(camera(a), camera(b), 1).lon, b);
+    assert.equal(
+      Math.abs(cameraAtProgress(camera(a), camera(b), 0.5).lon),
+      180,
+    );
+  }
+  // 10°E to 169.9°W is 179.9° westward through Greenwich, not 180.1° east.
+  const mid = cameraAtProgress(camera(10), camera(-169.9), 0.5).lon;
+  assert.ok(mid > -81 && mid < -79, `short arc midpoint, got ${mid}`);
+});
+
+test('director seek turns heading and roll the short way for any authored angles', () => {
+  const pose = (heading, roll) => ({ ...camera(0), heading, roll });
+  const mid = cameraAtProgress(pose(350, 350), pose(-350, -350), 0.5);
+  // 350° and -350° are 20° apart through 0°/360°, not 340° through 180°.
+  for (const value of [mid.heading, mid.roll]) {
+    const wrapped = ((value % 360) + 360) % 360;
+    assert.ok(wrapped < 1e-9 || 360 - wrapped < 1e-9, `got ${value}`);
+  }
+});

src/director/timeline.js

@@ -2,6 +2,7 @@ import {
   resolveCameraPose,
   resolveCameraMove,
   sampleCameraMove,
+  normalizeCameraLongitude,
 } from './camera.js';
 
 const DEFAULT_SHOT_DURATION_SEC = 4;
@@ -40,12 +41,19 @@ export function cameraAtProgress(fromCamera, toCamera, progress) {
   const lerp = (from, to) => Number(from) + (Number(to) - Number(from)) * eased;
   const lerpAngle = (from, to) => {
     const start = Number(from) || 0;
-    const delta = ((Number(to) - start + 540) % 360) - 180;
+    // Double modulo keeps the delta in [-180, 180) for any authored angles,
+    // as sampleCameraMove does; a single % goes negative below -540.
+    const delta = ((((Number(to) - start + 540) % 360) + 360) % 360) - 180;
     return start + delta * eased;
   };
   return {
     lat: lerp(source.lat, target.lat),
-    lon: lerp(source.lon, target.lon),
+    lon:
+      t === 0
+        ? Number(source.lon)
+        : t === 1
+          ? Number(target.lon)
+          : normalizeCameraLongitude(lerpAngle(source.lon, target.lon)),
     alt: lerp(source.alt, target.alt),
     heading: lerpAngle(source.heading, target.heading),
     pitch: lerp(source.pitch, target.pitch),