From 13f8023621aa7b8cbf8f230409b276c3e7764f43 Mon Sep 17 00:00:00 2001
From: fukunee <fukun.ee@foxmail.com>
Date: Sat, 19 Sep 2026 15:45:54 +0800
Subject: [PATCH] =?UTF-8?q?=E5=8F=B3=E9=94=AE=E7=8E=AF=E8=A7=86=EF=BC=9A?=
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---
 src/scene/CesiumGlobe.js | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/scene/CesiumGlobe.js b/src/scene/CesiumGlobe.js
index 4289847..581a595 100644
--- a/src/scene/CesiumGlobe.js
+++ b/src/scene/CesiumGlobe.js
@@ -383,6 +383,10 @@ export class CesiumGlobe {
       enu: new Cesium.Matrix4(),
       invEnu: new Cesium.Matrix4(),
       localDir: new Cesium.Cartesian3(),
+      enuUp: new Cesium.Cartesian3(),
+      u0: new Cesium.Cartesian3(),
+      un: new Cesium.Cartesian3(),
+      cross: new Cesium.Cartesian3(),
     };
 
     handler.setInputAction((movement) => {
@@ -477,9 +481,37 @@ export class CesiumGlobe {
     Cesium.Matrix4.multiplyByPointAsVector(sc.invEnu, dir, sc.localDir);
     const heading = Math.atan2(sc.localDir.x, sc.localDir.y);
     const pitch = Math.asin(sc.localDir.z);
+
+    // 计算“北朝上”所需的 roll：把 roll=0 的 up（水平线方向）滚转到“世界 Z 投影”的 up，
+    // 这样倾斜时 up 不随方向转动（否则会又倾斜又旋转）
+    const dz = dir.z;
+    sc.un.x = -dir.x * dz;
+    sc.un.y = -dir.y * dz;
+    sc.un.z = 1 - dz * dz;
+    if (Cesium.Cartesian3.magnitudeSquared(sc.un) < 1e-12) {
+      Cesium.Cartesian3.clone(s.up, sc.un);
+    } else {
+      Cesium.Cartesian3.normalize(sc.un, sc.un);
+    }
+    Cesium.Cartesian3.normalize(sc.newPos, sc.enuUp); // 径向 = newPos 处的“上”
+    const d0 = Cesium.Cartesian3.dot(sc.enuUp, dir);
+    sc.u0.x = sc.enuUp.x - d0 * dir.x;
+    sc.u0.y = sc.enuUp.y - d0 * dir.y;
+    sc.u0.z = sc.enuUp.z - d0 * dir.z;
+    let roll = 0;
+    if (Cesium.Cartesian3.magnitudeSquared(sc.u0) > 1e-12) {
+      Cesium.Cartesian3.normalize(sc.u0, sc.u0);
+      Cesium.Cartesian3.cross(sc.u0, sc.un, sc.cross);
+      const sin =
+        Cesium.Cartesian3.magnitude(sc.cross) *
+        Math.sign(Cesium.Cartesian3.dot(sc.cross, dir));
+      const cos = Cesium.Cartesian3.dot(sc.u0, sc.un);
+      roll = Math.atan2(sin, cos);
+    }
+
     camera.setView({
       destination: Cesium.Cartesian3.clone(sc.newPos),
-      orientation: { heading, pitch, roll: 0 },
+      orientation: { heading, pitch, roll },
     });
   }