Skip to content

Revert "Fix terminator line rendering artifact on the situation globe" #336

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
d3mocide merged 1 commit into from
Jul 10, 2026
Merged

Revert "Fix terminator line rendering artifact on the situation globe" #336

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
58 changes: 0 additions & 58 deletions agent_docs/tasks/2026-07-10-globe-terminator-chord-fix.md
View file
Open in desktop

This file was deleted.

48 changes: 0 additions & 48 deletions frontend/src/components/map/TerminatorLayer.test.ts
View file
Open in desktop

This file was deleted.

30 changes: 6 additions & 24 deletions frontend/src/components/map/TerminatorLayer.tsx
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -76,31 +76,13 @@ function computeTerminator(date: Date) {
// To make a polygon representing the *night* side, we need to connect the terminator
// to either the north or south pole, depending on season (subSolarLat).
// If sun is in north hemisphere (subSolarLat > 0), night covers south pole.
const poleLat = subSolarLat > 0 ? -90 : 90;

// These two closing edges run along a fixed meridian (lon = ±180) from the
// terminator curve to the pole. On flat/Mercator maps a single long edge is
// fine (it renders as a straight vertical line), but on the 3D globe the
// renderer only bends existing vertices onto the sphere and interpolates
// linearly *between* them — an edge spanning ~100+ degrees of latitude in
// one hop becomes a straight chord that cuts across the visible globe
// instead of following its curvature. Sample every few degrees so the
// edge hugs the sphere on both projections.
const LAT_STEP_DEG = 2;
const lastLat = coords[coords.length - 1][1]; // terminator lat at lon = 180
const firstLat = coords[0][1]; // terminator lat at lon = -180

const rampSteps = Math.max(1, Math.round(Math.abs(poleLat - lastLat) / LAT_STEP_DEG));
for (let i = 1; i <= rampSteps; i++) {
coords.push([180, lastLat + (poleLat - lastLat) * (i / rampSteps)]);
}

// Start this ramp exactly at the pole (i = returnSteps) so the pole-to-pole
// edge above lands on the same point in 3D at both ends, then step back
// down to the terminator curve's start.
const returnSteps = Math.max(1, Math.round(Math.abs(poleLat - firstLat) / LAT_STEP_DEG));
for (let i = returnSteps; i >= 1; i--) {
coords.push([-180, firstLat + (poleLat - firstLat) * (i / returnSteps)]);
if (subSolarLat > 0) {
coords.push([180, -90]);
coords.push([-180, -90]);
} else {
coords.push([180, 90]);
coords.push([-180, 90]);
}

// Close the polygon
Expand Down
Loading