fix(universe): a moons view relaxes the dimming of orbits outside its family as the camera pulls back

docs/universe-labels.md

@@ -85,7 +85,7 @@ A path's opacity follows from that:
 | Any path in an overview, or one the reader points at | Softens to 30% up close; never dimmed by family. |
 
 The outside dimming eases away between half and twice the host's distance from
-its star as the camera pulls back; a moons view holds it. Viewport clipping,
+its star as the camera pulls back, in a moons view too. Viewport clipping,
 body occlusion, the system's distance fade, the on-screen size fade and explicit
 hidden-orbit settings still apply.
 

packages/renderer/src/universe/context-presentation-policy.test.ts

@@ -59,14 +59,13 @@ test('the close-up fades keep a floor for context and none for the focused body\
   assert.deepEqual(closeOrbitFades(fade, .5), { context: .3, own: 0 });
 });
 
-test('the dimming outside a family relaxes as the camera reaches the parent system, and a moons view holds it', () => {
+test('the dimming outside a family relaxes as the camera reaches the parent system', () => {
   const host = { positionM: [10, 0, 0], orbit: { centerPositionM: [0, 0, 0] } };
-  const at = (distance: number, held = false) => outsideFamilyOrbitOpacity(host, () => distance, held);
+  const at = (distance: number) => outsideFamilyOrbitOpacity(host, () => distance);
   assert.deepEqual([at(1), at(5), at(20), at(100)], [.25, .25, 1, 1]);
   assert.ok(at(10) > .25 && at(10) < 1);
-  assert.equal(at(100, true), .25);
-  assert.equal(outsideFamilyOrbitOpacity(undefined, () => 1, false), 1);
-  assert.equal(outsideFamilyOrbitOpacity({ positionM: [0, 0, 0] }, () => 1, false), 1);
+  assert.equal(outsideFamilyOrbitOpacity(undefined, () => 1), 1);
+  assert.equal(outsideFamilyOrbitOpacity({ positionM: [0, 0, 0] }, () => 1), 1);
 });
 
 test('a moon is named inside the kept families, and beside a planet or a moon its star\'s minor bodies are not', () => {

packages/renderer/src/universe/context-presentation-policy.ts

@@ -28,7 +28,8 @@ export interface ContextSubject {
   readonly families: ReadonlySet<string>;
   /** A selected body's own page, with no flight: a host's page fades its moons' paths with the host. */
   readonly page: boolean;
-  /** A moons view is selected: the dimming outside the family holds at every range, the host's own path included. */
+  /** A moons view is selected: it holds its host as the subject, and the dimming outside the family includes the host's
+   * own path. */
   readonly held: boolean;
   /** Beside the page of a body that is not a system's star, that star's minor bodies are not named. */
   readonly quietMinors: boolean;
@@ -69,13 +70,13 @@ export function closeOrbitFades(fade: OrbitLineFade, discHeightShare: number) {
 /** An orbit belongs to the family it circles, not the body travelling on it, so a path outside the subject's family is
  * dim context: the other planets', and the host's own path about its star when the subject is not the host itself.
  * `host` is the family's host, absent without an emphasised body or when it is a star. The dimming relaxes from half to
- * twice the host's distance from its star, where the subject is the parent system again; a moons view holds it.
+ * twice the host's distance from its star, where the view is the parent system again; a moons view relaxes it too.
  * 1/64 steps avoid rewriting opacity for tiny camera changes. */
 export function outsideFamilyOrbitOpacity<Host extends { readonly positionM: readonly number[]; readonly orbit?: { readonly centerPositionM: readonly number[] } | null }>(
-  host: Host | undefined, cameraDistanceM: (host: Host) => number, held: boolean): number {
+  host: Host | undefined, cameraDistanceM: (host: Host) => number): number {
   if (!host?.orbit) return 1;
   const radiusM = Math.hypot(...host.positionM.map((value, axis) => value - host.orbit!.centerPositionM[axis]!));
-  const t = held || !(radiusM > 0) ? 0 : Math.max(0, Math.min(1, Math.log2(cameraDistanceM(host) / (.5 * radiusM)) / 2));
+  const t = !(radiusM > 0) ? 0 : Math.max(0, Math.min(1, Math.log2(cameraDistanceM(host) / (.5 * radiusM)) / 2));
   return 1 - (1 - OUTSIDE_FAMILY_OPACITY) * Math.round((1 - t * t * (3 - 2 * t)) * 64) / 64;
 }
 

packages/renderer/src/universe/world-context/world-context-planner.ts

@@ -191,7 +191,7 @@ export function createWorldContextPlanner(plan: PreparedWorldContext | PreparedW
         Math.abs(selectedY) < height / 2 + focusDiameter / 2;
       const focusShare = focusInView ? focusDiameter / height : 0;
       const fades = closeOrbitFades(plan.camera.presentation.orbitLineFade, focusShare);
-      const outsideFamily = outsideFamilyOrbitOpacity(subject.id === null || subject.hostIsStar ? undefined : byId.get(subject.hostId), host => Math.hypot(...frame.eye(host)), subject.held);
+      const outsideFamily = outsideFamilyOrbitOpacity(subject.id === null || subject.hostIsStar ? undefined : byId.get(subject.hostId), host => Math.hypot(...frame.eye(host)));
       const highlighting = bodies.some(entry => entry.highlighted === true), otherSystems = otherSystemsOpacity(systemFade.of(0), starFieldFade(focusDistanceM, plan.system));
       const near = opacity > 0
         ? Math.max(1, Math.min(...bodies.map(entry => Math.hypot(...frame.eye(entry.body)))) * 0.01) : 1;

packages/renderer/src/universe/world-context/world-context-system-selection.test.ts

@@ -35,11 +35,13 @@ test('a selected satellite overview retains its selected host locator', () => {
   const close = orbits(view), closePlain = orbits({ ...view, overviewSelection: false });
   const dimmed = orbits(wide), plain = orbits({ ...wide, overviewSelection: false });
   const hovered = orbits({ ...wide, bodies: wide.bodies.map((body, at) => at === index('saturn') ? { ...body, hovered: true } : body) });
-  for (const id of ['saturn', 'jupiter']) assert.deepEqual([dimmed.get(id), plain.get(id), hovered.get(id)], [.25, 1, id === 'saturn' ? 1 : .25], id);
+  assert.equal(close.get('jupiter'), .25);
   // On the host's own page its path is the subject's and stays whole; the other planets' paths are still context.
-  const page = orbits({ ...wide, overview: false, overviewSelection: false });
+  const page = orbits({ ...wide, overview: false, overviewSelection: false }), relaxed = page.get('saturn')!;
   assert.equal(page.get('jupiter'), 1);
-  assert.ok(page.get('saturn')! >= .25 && page.get('saturn')! < 1);
+  assert.ok(relaxed > .25 && relaxed < 1);
+  // Pulled back towards the parent system, the moons view relaxes the dimming as the page does, the host's own path with it.
+  for (const id of ['saturn', 'jupiter']) assert.deepEqual([dimmed.get(id), plain.get(id), hovered.get(id)], [relaxed, 1, id === 'saturn' ? 1 : relaxed], id);
   assert.ok(moons.some(id => close.get(id) === 1));
   for (const id of moons) assert.equal(close.get(id), closePlain.get(id), id);
   // One emphasis per body: a highlighted set dims the rest, another star's bodies read as not belonging inside the