修复楼层切换后无法返回建筑外观

src/components/map/ThreeMap.vue

@@ -543,6 +543,8 @@ const poiAmbientLabelServiceSpacingPx = 72
 const modelLoadRetryDelaysMs = [300, 900]
 const adjacentPreloadDelayMs = 900
 const manualAutoSwitchPauseMs = 1500
+const autoSwitchExitDistanceRatio = 0.2
+const autoSwitchExitDistanceMarginRatio = 0.08
 const poiMarkerVisualLiftFactor = 0.92
 const poiAmbientLabelLiftFactor = 2.1
 const poiFocusLabelLiftFactor = 2.72
@@ -3275,6 +3277,18 @@ const resetAutoSwitchDistanceTracking = () => {
   autoSwitchStateMachine.reset(activeView.value)
 }
 
+const ensureFloorAutoExitZoomRange = () => {
+  if (!controls) return
+
+  const distance = controls.getDistance()
+  if (!Number.isFinite(distance) || distance <= 0) return
+
+  // 楼层退出以当前距离的 120% 为阈值；参考外观相机正好处于原 600 上限时，
+  // 必须预留额外缩小空间，否则切层后无法满足自动返回外观的条件。
+  const requiredMaxDistance = distance * (1 + autoSwitchExitDistanceRatio + autoSwitchExitDistanceMarginRatio)
+  controls.maxDistance = Math.max(controls.maxDistance, requiredMaxDistance)
+}
+
 const handleWheelIntent = (event: WheelEvent) => {
   if (!controls || activeView.value !== 'overview' || event.deltaY === 0) return
 
@@ -3368,6 +3382,7 @@ const autoSwitchStateMachine = new GuideAutoSwitchStateMachine({
   exitHoldMs: 400,
   intentTimeoutMs: 2000,
   reverseToleranceRatio: 0.008,
+  exitRatio: autoSwitchExitDistanceRatio,
   cooldownMs: props.autoSwitchCooldown,
   canSwitch: canRunAutoSwitch,
   onSwitchRequested: requestAutoSwitch
@@ -3752,6 +3767,7 @@ const applyIndoorInitialModelTransform = (model: THREE.Object3D) => {
 const resetCamera = () => {
   applyReferenceOverviewCameraState()
   if (activeView.value === 'floor' && controls) {
+    ensureFloorAutoExitZoomRange()
     autoSwitchStateMachine.setFloorInitialDistance(controls.getDistance())
   }
   refreshPoiVisibilityByDistance()
@@ -4060,6 +4076,7 @@ const commitPreparedFloorScene = (
   }
   recordCameraSnapshotRestoration(cameraSnapshot, `floor:${expectedFloorId}`)
   if (controls) {
+    ensureFloorAutoExitZoomRange()
     autoSwitchStateMachine.setFloorInitialDistance(controls.getDistance())
   }
   options.onCameraStable?.()