src/app/TileBasemap.cpp

@@ -41,6 +41,8 @@ namespace {
 const char* kTk = "aca91d8c9f59a4f779f39061b8a07737";
 constexpr int kRadius = 4;            // 回退用：算不出可视范围时中心 ±4
 constexpr int kMaxTilesPerSide = 13;  // 单边瓦片上限(防倾斜时可视范围过大拉爆请求)
+constexpr int kBaseZoom = 13;         // 远处粗底层级(单块~4.9km)
+constexpr int kBaseRadius = 3;        // 粗底半径 ±3 → 7x7 覆盖~34km，填到天边
 constexpr int kMinZoom = 3;
 constexpr int kMaxZoom = 18;
 constexpr double kGroundZ = 0.0;      // 底图置于 z=0 地面参考（剖面深度向下为负，落其下）
@@ -137,15 +139,20 @@ void TileBasemap::show(Kind kind) {
     ++generation_;  // 旧回包(含换源前的层)按 generation 丢弃
     for (auto& kv : placed_) scene_.renderer()->RemoveViewProp(kv.second);
     placed_.clear();
+    for (auto& a : baseTiles_) scene_.renderer()->RemoveViewProp(a);
+    baseTiles_.clear();
+    baseLoaded_ = false;
     inFlight_.clear();
     desired_.clear();
     // demCache_/texCache_ 跨隐藏-重选保留 → 重选地图秒出，不重拉。
+    haveBaseline_ = false;  // 数据可能已换位置 → 重算基准高程
     terrainProbed_ = false;
     kind_ = kind;
     if (kind == Hidden) {
         if (rw_) rw_->Render();
         return;
     }
+    ensureBaseLayer();  // 先铺远处粗底(填到天边)，再叠近处精细
     refresh();
 }
 
@@ -362,6 +369,94 @@ void TileBasemap::placeActor(long long key, vtkSmartPointer<vtkActor> actor) {
     placed_[key] = actor;
 }
 
+void TileBasemap::ensureBaseline(const QImage& dem) {
+    if (haveBaseline_) return;  // 仅首块定基准 → base/detail 共用同一基准，地形连续无断层
+    baseline_ = demElev(dem, 0.5, 0.5);
+    haveBaseline_ = true;
+    double mn = 1e30, mx = -1e30;
+    for (int yy = 0; yy < dem.height(); yy += 16)
+        for (int xx = 0; xx < dem.width(); xx += 16) {
+            const double e = demElev(dem, xx / double(dem.width() - 1), yy / double(dem.height() - 1));
+            mn = std::min(mn, e);
+            mx = std::max(mx, e);
+        }
+    qInfo() << "[basemap] 地形启用 baseline=" << baseline_ << "m 起伏=" << (mx - mn) << "m";
+}
+
+void TileBasemap::ensureBaseLayer() {
+    if (baseLoaded_ || kind_ != Satellite) return;
+    baseLoaded_ = true;
+    const auto c = frame_->toLatLon(0.0, 0.0);  // 数据中心(show 在重锚后调 → 已对准数据)
+    const geopro::render::TileXY ct = geopro::render::lonLatToTile(c.lon, c.lat, kBaseZoom);
+    const int n = 1 << kBaseZoom;
+    for (int dy = -kBaseRadius; dy <= kBaseRadius; ++dy)
+        for (int dx = -kBaseRadius; dx <= kBaseRadius; ++dx) {
+            const int tx = ct.x + dx, ty = ct.y + dy;
+            if (tx < 0 || ty < 0 || tx >= n || ty >= n) continue;
+            fetchBaseTile(kBaseZoom, tx, ty);
+        }
+}
+
+void TileBasemap::fetchBaseTile(int z, int x, int y) {
+    const int gen = generation_;
+    const long long key = tileKey(z, x, y);
+
+    // 有了卫星纹理后 → 取 DEM(base zoom ≤ kDemMaxZoom, 同级) → warp 成持久粗底块。
+    auto onTex = [this, z, x, y, gen](vtkSmartPointer<vtkTexture> tex) {
+        const long long demKey = tileKey(z, x, y);
+        auto placeBase = [this, z, x, y, gen, tex](const QImage* dem) {
+            if (gen != generation_ || kind_ != Satellite) return;  // 已隐藏/换源 → 丢弃
+            vtkSmartPointer<vtkActor> a;
+            if (dem && !dem->isNull()) {
+                ensureBaseline(*dem);
+                a = buildWarped(z, x, y, z, x, y, tex, *dem);
+            } else {
+                a = buildFlat(z, x, y, tex);
+            }
+            a->SetUseBounds(false);  // 粗底不参与包围盒/取景
+            scene_.addActor(a);
+            baseTiles_.push_back(a);
+            if (rw_) rw_->Render();
+        };
+        auto dc = demCache_.find(demKey);
+        if (dc != demCache_.end()) { placeBase(&dc->second); return; }
+        const QString durl =
+            QStringLiteral("https://api.mapbox.com/v4/mapbox.terrain-rgb/%1/%2/%3.pngraw?access_token=%4")
+                .arg(z).arg(x).arg(y).arg(QString::fromLatin1(kMapboxToken));
+        QNetworkReply* dr = nam_.get(QNetworkRequest(QUrl(durl)));
+        connect(dr, &QNetworkReply::finished, this, [this, dr, demKey, gen, placeBase]() {
+            dr->deleteLater();
+            if (gen != generation_) return;
+            QImage dem;
+            if (dr->error() == QNetworkReply::NoError && dem.loadFromData(dr->readAll())) {
+                demCache_[demKey] = dem;
+                placeBase(&dem);
+            } else {
+                placeBase(nullptr);
+            }
+        });
+    };
+
+    auto tc = texCache_.find(key);
+    if (tc != texCache_.end()) { onTex(tc->second); return; }
+    const int sub = (x + y) % 8;
+    const QString url =
+        QStringLiteral("http://t%1.tianditu.gov.cn/img_w/wmts?service=wmts&request=GetTile"
+                       "&version=1.0.0&LAYER=img&tileMatrixSet=w&TileMatrix=%2&TileRow=%3"
+                       "&TileCol=%4&style=default&format=tiles&tk=%5")
+            .arg(sub).arg(z).arg(y).arg(x).arg(QString::fromLatin1(kTk));
+    QNetworkReply* reply = nam_.get(QNetworkRequest(QUrl(url)));
+    connect(reply, &QNetworkReply::finished, this, [this, reply, key, gen, onTex]() {
+        reply->deleteLater();
+        if (gen != generation_ || kind_ != Satellite) return;
+        QImage img;
+        if (reply->error() != QNetworkReply::NoError || !img.loadFromData(reply->readAll())) return;
+        auto tex = makeTexture(img);
+        texCache_[key] = tex;
+        onTex(tex);
+    });
+}
+
 vtkSmartPointer<vtkActor> TileBasemap::buildFlat(int z, int x, int y,
                                                  vtkSmartPointer<vtkTexture> tex) {
     const geopro::render::LonLatBox b = geopro::render::tileBounds(z, x, y);
@@ -395,20 +490,7 @@ void TileBasemap::fetchTerrain(int z, int x, int y, long long key, vtkSmartPoint
     // 落地一块瓦片：DEM 有效→起伏，否则→平面兜底；并推进 inFlight/清理。
     auto place = [this, key, z, x, y, dz, dx, dy, tex](const QImage* dem) {
         if (dem && !dem->isNull()) {
-            if (!haveBaseline_) {  // 基准高程取首块中心 → 地形整体绕 z=0 起伏
+            ensureBaseline(*dem);  // 首块定基准(base/detail 共用)→ 地形连续
-                baseline_ = demElev(*dem, 0.5, 0.5);
-                haveBaseline_ = true;
-                double mn = 1e30, mx = -1e30;
-                for (int yy = 0; yy < dem->height(); yy += 16)
-                    for (int xx = 0; xx < dem->width(); xx += 16) {
-                        const double e = demElev(*dem, xx / double(dem->width() - 1),
-                                                 yy / double(dem->height() - 1));
-                        mn = std::min(mn, e);
-                        mx = std::max(mx, e);
-                    }
-                qInfo() << "[basemap] 地形启用 baseline=" << baseline_ << "m 起伏=" << (mx - mn)
-                        << "m";
-            }
             placeActor(key, buildWarped(z, x, y, dz, dx, dy, tex, *dem));
         } else {
             placeActor(key, buildFlat(z, x, y, tex));  // DEM 拉不到 → 平面兜底

src/app/TileBasemap.hpp

@@ -7,6 +7,7 @@
 #include <map>
 #include <memory>
 #include <set>
+#include <vector>
 
 #include <vtkSmartPointer.h>
 
@@ -46,6 +47,9 @@ private:
     void fetchTerrain(int z, int x, int y, long long key,
                       vtkSmartPointer<vtkTexture> tex);  // 拉覆盖该瓦片的 DEM(z>15 取祖先块)后落地
     void placeActor(long long key, vtkSmartPointer<vtkActor> actor);
+    void ensureBaseline(const QImage& dem);  // 首块 DEM 定基准高程(base/detail 共用→地形连续)
+    void ensureBaseLayer();                  // 远处粗底图层(填到天边,治倾斜露黑边)
+    void fetchBaseTile(int z, int x, int y); // 单块粗底(sat+DEM→warp,持久不purge)
     vtkSmartPointer<vtkActor> buildFlat(int z, int x, int y,
                                         vtkSmartPointer<vtkTexture> tex);  // 平面瓦片(DEM 兜底)
     vtkSmartPointer<vtkActor> buildWarped(int sz, int sx, int sy, int dz, int dx, int dy,
@@ -64,6 +68,8 @@ private:
     std::set<long long> inFlight_;                          // 在途瓦片(续到起伏/平面最终落地)
     std::map<long long, QImage> demCache_;                  // DEM 块缓存(key=DEMz/x/y)，跨隐藏/重选复用
     std::map<long long, vtkSmartPointer<vtkTexture>> texCache_;  // 影像纹理缓存，重选/缩放回看免重拉
+    std::vector<vtkSmartPointer<vtkActor>> baseTiles_;     // 远处粗底层(持久,不随相机purge)
+    bool baseLoaded_ = false;
     double baseline_ = 0.0;                                 // 基准高程(首块中心)，地形绕 z=0 起伏
     bool haveBaseline_ = false;
     bool terrainProbed_ = false;                           // 首次 fetchTerrain 打一行诊断日志