avalon-vanguard/star-map
2
0
Fork 0
Code Issues Pull Requests 1 Actions Packages Projects Releases Wiki Activity

Name the brightest stars by walking one order, instead of sorting 60 000 five times a second

Browse Source 
The star labels are refreshed every 0.2 s. Each pass filtered the whole
catalogue to the stars within the label radius, sorted them by magnitude,
and turned every one into a label object, all to place at most fifteen.
At the opening view the radius holds about 60 000 stars, so each pass was a
55-70 ms task on the main thread. A CPU profile of the opening view, on a
Ryzen 7700X with an RTX 4080, counted 29 tasks over 50 ms in 6.7 s, one
every 230 ms; updateLabels took 23% of the main thread. That is the stutter
the frame-time bench measured on every GPU and every render budget.

The catalogue is now sorted by brightness once, when it loads.
brightestWithin walks that order and hands stars over lazily, and
spreadLabels already stopped once it had placed fifteen labels, so a pass
reads only the stars it looks at. The output is the same as before: the
same stars, in the same order, with ties in catalogue order, the selected
star named wherever it is, and a star exactly on the radius included. The
spec checks it against the filter-then-sort it replaces. Stars are no longer
scanned at all when the view is at galactic scale, where the result was
thrown away.

Profiled again on the same view: 0 tasks over 50 ms, and the scene's
per-frame work over the window dropped from 2 028 ms to 342 ms.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016jxMkwA2rbicdGxHosecYi
This commit is contained in:
Senrokai
2026-09-16 13:52:51 +02:00
co-authored by Claude Opus 5
parent efe6667b00
commit 0a0b301807
3 changed files with 161 additions and 35 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/app/features/galaxy-system/galaxy-system-scene.component.ts
+19 -35
View File
@@ -38,6 +38,7 @@ import { StarmapHudComponent } from './starmap-hud.component';
import { SystemObjectCardComponent } from './system-object-card.component';
import { colorIndexToRgb, StarFieldRenderer, starRenderBudgetFromUrl } from './star-field-renderer';
import { collectJumpLinks, minimumRangeBetween, routeBetween } from '../../shared/astro/jump-links';
import { brightestWithin, brightnessOrder } from '../../shared/astro/brightest';
import { StarNeighbourhood } from '../../shared/astro/star-neighbourhood';
import { MAX_JUMP_RANGE_PC } from '../hud/routes-panel.component';
import { HostStarRings } from './host-star-rings';
@@ -356,6 +357,8 @@ export class GalaxySystemSceneComponent implements AfterViewInit, OnDestroy {
private deepSkyLabels: readonly LabeledPoint[] = [];
/** Stars with at least one catalogued body, which are the ones the map can be flown into. */
private starIdsWithBodies = new Set<number>();
/** Catalogue indices, brightest first, for the labels to walk rather than sort. See `brightestWithin`. */
private starsByBrightness: Uint32Array = new Uint32Array(0);
/** Stars alone, normalised once, for the two routing fields. Empty until the catalogue lands. */
private readonly starSearchIndex = signal<IndexedSearchEntry[]>([]);
private milkyWay?: MilkyWayRenderer;
@@ -518,6 +521,7 @@ export class GalaxySystemSceneComponent implements AfterViewInit, OnDestroy {
this.stars = stars;
this.starsById = new Map(stars.map((star) => [star.id, star]));
this.neighbourhood = new StarNeighbourhood(stars);
this.starsByBrightness = brightnessOrder(stars);
this.starSearchIndex.set(
buildSearchIndex(stars.map((star) => ({ kind: 'star' as const, name: star.name, subtitle: star.spectralType, starId: star.id })))
);
@@ -766,47 +770,27 @@ export class GalaxySystemSceneComponent implements AfterViewInit, OnDestroy {
// orbit distance, so a camera-relative rule names the stars closest to the near edge of the
// view — a ring of labels around the outside of the thing the user is actually looking at.
const target = this.controls?.target ?? GALAXY_OVERVIEW_TARGET;
const { x: cx, y: cy, z: cz } = target;
const orbitDistance = (this.controls ? this.effectiveDistance(camera) : GALAXY_OVERVIEW_POSITION.length()) * LABEL_RADIUS_TO_ORBIT_DISTANCE;
const labelRadius = THREE.MathUtils.clamp(orbitDistance, MIN_LABEL_RADIUS_PC, MAX_LABEL_RADIUS_PC);
const maxDistanceSq = labelRadius * labelRadius;
const candidates: Array<{ star: StarRecord; distanceSq: number }> = [];
for (const star of this.stars) {
const dx = star.x - cx;
const dy = star.y - cy;
const dz = star.z - cz;
const distanceSq = dx * dx + dy * dy + dz * dz;
if (distanceSq <= maxDistanceSq || star.id === selectedId) {
candidates.push({ star, distanceSq });
}
}
// Individual star names mean nothing once the whole Galaxy is in frame — at that range the
// entire catalogue is inside one pixel — so the labels hand over to the structural ones.
const isGalactic = this.galacticStrength >= GALACTIC_LEVEL_THRESHOLD;
// Brightest first, not nearest first. Proximity was the right ranking when the catalogue was
// a 50 pc bubble and everything in it was equally worth naming; across 250 pc it labels a
// clump of whatever happens to be closest to the middle of the screen and never names the
// stars that are actually prominent. Brightness is what makes a star worth a name.
candidates.sort((a, b) => a.star.magnitude - b.star.magnitude);
// Individual star names mean nothing once the whole Galaxy is in frame — at that range the
// entire catalogue is inside one pixel — so the labels hand over to the structural ones.
const isGalactic = this.galacticStrength >= GALACTIC_LEVEL_THRESHOLD;
// "System" rather than "Star" for anything with catalogued bodies: it is the one distinction
// the second line can draw that the map cannot otherwise show, since it says which of these
// points is somewhere you can actually go.
const starLabels: LabeledPoint[] = isGalactic
? []
: this.spreadLabels(
candidates.map(({ star }) => ({
id: star.id,
name: star.name,
kind: this.starIdsWithBodies.has(star.id) ? 'System' : 'Star',
x: star.x,
y: star.y,
z: star.z
})),
camera,
selectedId
);
//
// Walked lazily, and only as far as it takes to place the labels. "System" rather than "Star"
// for anything with catalogued bodies: it is the one distinction the second line can draw that
// the map cannot otherwise show, since it says which of these points is somewhere you can go.
const starIdsWithBodies = this.starIdsWithBodies;
const candidates = function* (stars: readonly StarRecord[], order: Uint32Array): Generator<LabeledPoint> {
for (const star of brightestWithin(stars, order, target, labelRadius, selectedId)) {
yield { id: star.id, name: star.name, kind: starIdsWithBodies.has(star.id) ? 'System' : 'Star', x: star.x, y: star.y, z: star.z };
}
};
const starLabels: LabeledPoint[] = isGalactic ? [] : this.spreadLabels(candidates(this.stars, this.starsByBrightness), camera, selectedId);
const backdropLabels = isGalactic ? this.galacticLabels : this.deepSkyLabels;
const ringLabels = isGalactic || !this.display().grid ? [] : this.ringLabels(camera);
this.labelOverlay?.update([...starLabels, ...ringLabels, ...backdropLabels]);
@@ -831,7 +815,7 @@ export class GalaxySystemSceneComponent implements AfterViewInit, OnDestroy {
return canvas.clientHeight > 0 ? canvas.clientWidth / canvas.clientHeight : 1;
}
private spreadLabels(candidates: readonly LabeledPoint[], camera: SceneCamera, keepId: number | string | null): LabeledPoint[] {
private spreadLabels(candidates: Iterable<LabeledPoint>, camera: SceneCamera, keepId: number | string | null): LabeledPoint[] {
const placed: THREE.Vector2[] = [];
const chosen: LabeledPoint[] = [];
const projected = new THREE.Vector3();