From fb43237830dedf09de461941db5c2f95364771b8 Mon Sep 17 00:00:00 2001
From: gaozheng <gaozheng.cn@gmail.com>
Date: Wed, 17 Jun 2026 15:19:16 +0800
Subject: [PATCH] =?UTF-8?q?fix(vtk):=20=E4=BF=AE=E5=9E=82=E7=9B=B4?=
 =?UTF-8?q?=E5=81=8F=E7=A7=BB=E6=A0=B9=E5=9B=A0-=E5=9B=9B=E5=8F=89?=
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 =?UTF-8?q?warp=E6=8A=8A=E5=9C=B0=E5=BD=A2=E6=8A=AC=E9=AB=98;=E6=94=B9show?=
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---
 src/app/TileBasemap.cpp | 31 ++++++++++++++++++++++++++++++-
 src/app/TileBasemap.hpp |  1 +
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/src/app/TileBasemap.cpp b/src/app/TileBasemap.cpp
index 2055cf6..4535bb6 100644
--- a/src/app/TileBasemap.cpp
+++ b/src/app/TileBasemap.cpp
@@ -182,7 +182,36 @@ void TileBasemap::show(Kind kind) {
         requestRender();
         return;
     }
-    refresh();  // 四叉树覆盖：近细远粗一次铺满（含远处粗块，无需单独粗底层）
+    primeBaselineThenRefresh();  // 先定基准高程再铺瓦片：避免先到的粗块用错基准把地形整体抬高
+}
+
+void TileBasemap::primeBaselineThenRefresh() {
+    if (haveBaseline_ || kind_ != Satellite) { refresh(); return; }
+    // 先拉"含数据中心"的 DEM 块定基准(z15)，确保任何瓦片 warp 前基准已就位、全场一致。
+    const auto c = frame_->toLatLon(0.0, 0.0);
+    const int z = kDemMaxZoom;
+    const geopro::render::TileXY t = geopro::render::lonLatToTile(c.lon, c.lat, z);
+    const long long demKey = tileKey(z, t.x, t.y);
+    auto cached = demCache_.find(demKey);
+    if (cached != demCache_.end()) {
+        ensureBaseline(z, t.x, t.y, cached->second);
+        refresh();
+        return;
+    }
+    const int gen = generation_;
+    const QString url =
+        QStringLiteral("https://api.mapbox.com/v4/mapbox.terrain-rgb/%1/%2/%3.pngraw?access_token=%4")
+            .arg(z).arg(t.x).arg(t.y).arg(QString::fromLatin1(kMapboxToken));
+    enqueueGet(url, [this, z, t, demKey, gen](QNetworkReply* r) {
+        r->deleteLater();
+        if (gen != generation_) return;
+        QImage dem;
+        if (r->error() == QNetworkReply::NoError && dem.loadFromData(r->readAll())) {
+            demCache_[demKey] = dem;
+            ensureBaseline(z, t.x, t.y, dem);
+        }
+        refresh();  // 成功→基准就位；失败→baseline=0 兜底，但仍全场一致
+    });
 }
 
 void TileBasemap::refineTile(int z, int x, int y, std::set<long long>& out, int& count) {
diff --git a/src/app/TileBasemap.hpp b/src/app/TileBasemap.hpp
index 42d8797..1a69278 100644
--- a/src/app/TileBasemap.hpp
+++ b/src/app/TileBasemap.hpp
@@ -43,6 +43,7 @@ private:
     static long long tileKey(int z, int x, int y);
     void ensureObserver();  // 首次显示时挂到交互样式的 EndInteractionEvent
     void requestRender();   // 合并渲染：同一事件循环轮次多次请求只渲染一帧
+    void primeBaselineThenRefresh();  // 先定数据中心基准高程，再铺四叉树(保证所有瓦片同一基准)
     void purgeStale();      // 本轮请求全部落地后再删旧层瓦片，避免缩放空白闪烁
     // 四叉树细分：按瓦片投影屏幕尺寸递归(近细远粗)，收集叶瓦片到 out。
     void refineTile(int z, int x, int y, std::set<long long>& out, int& count);