From d82bd4d78ea94625cac1b19170f9b18ab177e861 Mon Sep 17 00:00:00 2001
From: Anton Afanasyeu <a.afanasieff@gmail.com>
Date: Wed, 5 Aug 2026 17:00:15 +0200
Subject: [PATCH] Hub globe3d=10: v4 latitude arcs with screen-Y strip depth.

Hub 2D ellipses (v8) are not latitude circles and fail when rotated.
Use v4 sphere arcs plus hub ry vertical thickness clipped at limb.

Co-authored-by: Cursor <cursoragent@cursor.com>
---
 assets/hub-globe.js | 98 ++++++++++++++++++++++++++++++++++++++++++++-
 index.php           |  2 +-
 2 files changed, 97 insertions(+), 3 deletions(-)

diff --git a/assets/hub-globe.js b/assets/hub-globe.js
index 0284c46..946ae61 100644
--- a/assets/hub-globe.js
+++ b/assets/hub-globe.js
@@ -8,8 +8,9 @@
  * globe3d=5: hub ellipse trace (deprecated — breaks under rotation).
  * globe3d=6: v4 math + latitude band fill (continuous arc paths).
  * globe3d=7: v4 math + wide centerline stroke bands (no fill quads).
- * globe3d=8: hub SVG ellipse → sphere trace, wide stroke, gap-safe (ellipses at rest).
- * globe3d=9: v8 parallels + v4 sphere meridians (split best-of).
+ * globe3d=8: hub SVG ellipse trace (breaks under rotation — deprecated).
+ * globe3d=9: reserved / same as 10.
+ * globe3d=10: v4 latitude arcs + screen-Y strip thickness (hub ry), limb-clipped.
  */
 export const GLOBE_VIEW = { imgW: 1920, imgH: 1080, cx: 720, cy: 560, r: 322, rim: 330 };
 
@@ -549,6 +550,99 @@ function drawHubEllipseGridRotated(ctx, cx, cy, r, rotY, layoutScale) {
   ctx.restore();
 }
 
+/** v4 latitude arc with hub ry as vertical screen thickness — rotates correctly. */
+function fillParallelScreenStrip(ctx, cx, cy, r, rotY, par) {
+  const halfPx = (par.bright ? HUB_EW_PARALLELS[0].ry : HUB_EW_PARALLELS[1].ry) * (r / GLOBE_VIEW.r);
+  const ring = parallelBodyRingAtLat(par.lat, SPHERE_AXIS_STEPS);
+  const rgb = par.bright ? '219,231,246' : '231,236,243';
+  let run = [];
+
+  function flushFill() {
+    if (run.length < 2) {
+      run = [];
+      return;
+    }
+    let zSum = 0;
+    for (let k = 0; k < run.length; k++) {
+      zSum += run[k].z;
+    }
+    const zAvg = zSum / run.length;
+    const t = Math.max(0, Math.min(1, (zAvg - LIMB_Z) / (0.95 - LIMB_Z)));
+    if (t <= 0) {
+      run = [];
+      return;
+    }
+    const alpha = (par.bright ? 0.16 + 0.48 * t : 0.09 + 0.34 * t).toFixed(3);
+    ctx.beginPath();
+    for (let k = 0; k < run.length; k++) {
+      ctx.lineTo(run[k].sx, run[k].sy - halfPx);
+    }
+    for (let k = run.length - 1; k >= 0; k--) {
+      ctx.lineTo(run[k].sx, run[k].sy + halfPx);
+    }
+    ctx.closePath();
+    ctx.fillStyle = 'rgba(' + rgb + ',' + alpha + ')';
+    ctx.fill();
+    run = [];
+  }
+
+  for (let i = 0; i < ring.length; i++) {
+    const view = bodyToView(ring[i], rotY);
+    if (view.z <= LIMB_Z) {
+      flushFill();
+      continue;
+    }
+    run.push({
+      sx: cx + view.x * r,
+      sy: cy - view.y * r,
+      z: view.z,
+    });
+  }
+  flushFill();
+
+  strokeBodyRing(
+    ctx,
+    cx,
+    cy,
+    r,
+    rotY,
+    ring,
+    function (z) {
+      return parallelStyle(par.bright, 1, z, LIMB_Z);
+    },
+    LIMB_Z
+  );
+}
+
+/** globe3d=10 — v4 E–W arcs, screen-vertical band; v4 meridians. */
+function drawSphereGridScreenStrip(ctx, cx, cy, r, rotY, layoutScale) {
+  ctx.save();
+  ctx.beginPath();
+  ctx.arc(cx, cy, r, 0, Math.PI * 2);
+  ctx.clip();
+
+  SPHERE_PARALLELS.forEach(function (par) {
+    fillParallelScreenStrip(ctx, cx, cy, r, rotY, par);
+  });
+
+  SPHERE_MERIDIANS.forEach(function (mer) {
+    strokeBodyRing(
+      ctx,
+      cx,
+      cy,
+      r,
+      rotY,
+      meridianBodyRingAtLon(mer.lon, SPHERE_AXIS_STEPS),
+      function (z) {
+        return meridianStyle(mer.prime, layoutScale, z, LIMB_Z);
+      },
+      LIMB_Z
+    );
+  });
+
+  ctx.restore();
+}
+
 /** globe3d=7 — v4 sphere model, wide stroke bands (no path fill). */
 function drawSphereGridWideStroke(ctx, cx, cy, r, rotY, layoutScale, opts) {
   const parallelsOnly = !!(opts && opts.parallelsOnly);
diff --git a/index.php b/index.php
index 686f990..f0ba7b5 100644
--- a/index.php
+++ b/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 = '20260704globe8';
+      var logoBuild = '20260704globe10';
 
       function hubAsset(rel) {
         var link = document.querySelector('link[href*="hub.css"]');