feat(globe3d=11): ?f= URL param for N-S latitude factor tuning

Default remains 0.66; exposed on #hub-logo-stage as data-globe-lat-factor.

Co-authored-by: Cursor <cursoragent@cursor.com>

assets/hub-globe.js

@@ -12,6 +12,7 @@
  * globe3d=9: v4 sphere grid only (thin E–W + N–S) — proper rotation baseline.
  * globe3d=10: v4 visible-arc → screen ellipse (hub ry), disk-clipped.
  * globe3d=11: v10 grid + geographic mercator-flat land (360° U-wrap).
+ *   ?f=0.66 — N–S latitude factor (default 0.66; lower = more squeeze).
  */
 export const GLOBE_VIEW = { imgW: 1920, imgH: 1080, cx: 720, cy: 560, r: 322, rim: 330 };
 
@@ -29,8 +30,15 @@ const CONTINENT_INNER_SX = 1.2408477842003853;
 const CONTINENT_INNER_SY = 1.2408477842003853;
 /** Map plate center longitude (extract_red_polygons.py CENTER_LON). */
 const MERCATOR_LON_CENTER = (12 * Math.PI) / 180;
-/** N–S latitude factor on mercator sample (0.75 = lat × 0.75). */
-const CONTINENT_LAT_FACTOR = 0.66;
+/** Default N–S latitude factor (override with ?f= on globe3d=11). */
+const CONTINENT_LAT_FACTOR_DEFAULT = 0.66;
+
+function resolveContinentLatFactor(raw) {
+  if (typeof raw !== 'number' || !isFinite(raw)) {
+    return CONTINENT_LAT_FACTOR_DEFAULT;
+  }
+  return Math.max(0.05, Math.min(2, raw));
+}
 const RASTER_SCALE = 2;
 const AXIS_STEPS = 160;
 const SPHERE_AXIS_STEPS = 180;
@@ -953,10 +961,10 @@ function sampleFlatPlateFromHub(mercFlat, hpX, hpY) {
 }
 
 /** Sphere tex → mercator-flat plate (lon center + inverse Mercator Y). */
-function sampleMercFlatFromTex(mercFlat, tex) {
+function sampleMercFlatFromTex(mercFlat, tex, latFactor) {
   const ll = texLonLat(tex);
   const lon = wrapLon(ll.lon + MERCATOR_LON_CENTER);
-  const lat = Math.max(-1.52, Math.min(1.52, ll.lat * CONTINENT_LAT_FACTOR));
+  const lat = Math.max(-1.52, Math.min(1.52, ll.lat * latFactor));
   return sampleMercFlat(mercFlat, lon, lat);
 }
 
@@ -1069,11 +1077,11 @@ function sampleLandRgbaMercator(mercFlat, tex) {
 }
 
 /** globe3d=11 — geographic mercator wrap (360°); z > LIMB_Z only. */
-function sampleLandVisibleHemisphere(mercFlat, tex) {
+function sampleLandVisibleHemisphere(mercFlat, tex, latFactor) {
   if (tex.z <= LIMB_Z) {
     return null;
   }
-  const flat = sampleMercFlatFromTex(mercFlat, tex);
+  const flat = sampleMercFlatFromTex(mercFlat, tex, latFactor);
   if (isHubContinentPixel(flat[0], flat[1], flat[2], flat[3])) {
     return hubContinentRgba(flat);
   }
@@ -1179,6 +1187,7 @@ export async function mountHubGlobe(stage, opts) {
   const build = opts.build || 'earth3d';
   const reducedMotion = !!opts.reducedMotion;
   const renderVersion = Math.max(1, parseInt(opts.renderVersion, 10) || 1);
+  const continentLatFactor = resolveContinentLatFactor(opts.continentLatFactor);
 
   const canvas = document.createElement('canvas');
   canvas.className = 'hub-globe-canvas';
@@ -1290,7 +1299,7 @@ export async function mountHubGlobe(stage, opts) {
         cy,
         r,
         fillDiskRegion(ctx, cx, cy, r, rotation, function (tex) {
-          const l = sampleLandVisibleHemisphere(mercFlat, tex);
+          const l = sampleLandVisibleHemisphere(mercFlat, tex, continentLatFactor);
           return l || [0, 0, 0, 0];
         })
       );
@@ -1365,6 +1374,9 @@ export async function mountHubGlobe(stage, opts) {
 
   raf = requestAnimationFrame(tick);
   stage.dataset.globe3d = String(renderVersion);
+  if (renderVersion >= 11) {
+    stage.dataset.globeLatFactor = String(continentLatFactor);
+  }
   stage.dataset.globeAxis =
     renderVersion === 11
       ? 'ew-sphere-ellipse-land'
@@ -1393,6 +1405,7 @@ export async function mountHubGlobe(stage, opts) {
       canvas.remove();
       delete stage.dataset.globe3d;
       delete stage.dataset.globeAxis;
+      delete stage.dataset.globeLatFactor;
     },
   };
 }

index.php

@@ -187,7 +187,7 @@ function hub_h(string $s): string {
       var supportsLayout = !!(window.CSS && CSS.supports && CSS.supports('object-fit', 'cover'));
       var logoEnabled = !!(stage && supportsSvg && supportsLayout);
 
-      var logoBuild = '20260704globe24';
+      var logoBuild = '20260704globe25';
 
       function hubAsset(rel) {
         var link = document.querySelector('link[href*="hub.css"]');
@@ -256,6 +256,10 @@ function hub_h(string $s): string {
       var globe3dRaw = params.get('globe3d');
       var globe3dVersion = globe3dRaw === null || globe3dRaw === '' ? 1 : parseInt(globe3dRaw, 10);
       if (!isFinite(globe3dVersion)) globe3dVersion = 1;
+      var globeLatFactorRaw = params.get('f');
+      var globeLatFactor = globeLatFactorRaw === null || globeLatFactorRaw === ''
+        ? NaN
+        : parseFloat(globeLatFactorRaw);
       var useGlobe3d = logoEnabled && globe3dVersion !== 0;
       var globe3dLayers = { globe: true, continents: true, gridOverlay: true };
 
@@ -300,6 +304,9 @@ function hub_h(string $s): string {
           if (isFinite(globeYawDeg)) {
             globeOpts.initialRotationY = globeYawDeg * Math.PI / 180;
           }
+          if (isFinite(globeLatFactor)) {
+            globeOpts.continentLatFactor = globeLatFactor;
+          }
           var globeModuleUrl = new URL('assets/hub-globe.js', window.location.href);
           globeModuleUrl.searchParams.set('v', logoBuild);
           globeModuleUrl.searchParams.set('globe3d', String(globe3dVersion));