src/app/TileBasemap.cpp

@@ -14,11 +14,15 @@
 #include <vtkCallbackCommand.h>
 #include <vtkCamera.h>
 #include <vtkCommand.h>
+#include <vtkDataArray.h>
 #include <vtkImageData.h>
 #include <vtkInteractorObserver.h>
 #include <vtkNew.h>
 #include <vtkPlaneSource.h>
+#include <vtkPointData.h>
+#include <vtkPolyData.h>
 #include <vtkPolyDataMapper.h>
+#include <vtkPoints.h>
 #include <vtkProperty.h>
 #include <vtkRenderWindow.h>
 #include <vtkRenderWindowInteractor.h>
@@ -44,12 +48,28 @@ constexpr double kPi = 3.14159265358979323846;
 constexpr double kEarthCirc = 40075016.686;  // 赤道周长(米) = z0 单瓦片地面尺寸
 constexpr double kTilesAcross = 4.0;          // 视野跨度目标覆盖瓦片数（决定层级）
 
+// 地面起伏：AWS Terrarium DEM 瓦片(免费/无 token，XYZ Web-Mercator 与卫星瓦片对齐)。
+// elev(米) = R*256 + G + B/256 - 32768。数据到约 z15，更高层级无 DEM → 保持平面。
+constexpr int kDemMaxZoom = 15;
+constexpr int kTerrainGrid = 32;        // 每瓦片网格分辨率(33x33 顶点)
+constexpr double kTerrainExag = 1.0;    // 地形垂向夸张(1=真实高程)
+
 // key 打包：z<<44 | x<<22 | y（z≤18, x/y<2^18 < 2^22）。
 void unpackKey(long long key, int& z, int& x, int& y) {
     z = static_cast<int>(key >> 44);
     x = static_cast<int>((key >> 22) & 0x3FFFFF);
     y = static_cast<int>(key & 0x3FFFFF);
 }
+
+// Terrarium 像素解码高程：(fx,fy)∈[0,1]，fy=0 北/顶行。
+double demElev(const QImage& dem, double fx, double fy) {
+    const int w = dem.width(), h = dem.height();
+    if (w <= 0 || h <= 0) return 0.0;
+    const int px = std::clamp(static_cast<int>(std::lround(fx * (w - 1))), 0, w - 1);
+    const int py = std::clamp(static_cast<int>(std::lround(fy * (h - 1))), 0, h - 1);
+    const QRgb c = dem.pixel(px, py);
+    return qRed(c) * 256.0 + qGreen(c) + qBlue(c) / 256.0 - 32768.0;
+}
 }  // namespace
 
 long long TileBasemap::tileKey(int z, int x, int y) {
@@ -91,6 +111,7 @@ void TileBasemap::show(Kind kind) {
     for (auto& kv : placed_) scene_.renderer()->RemoveViewProp(kv.second);
     placed_.clear();
     inFlight_.clear();
+    terrainInFlight_.clear();
     desired_.clear();
     kind_ = kind;
     if (kind == Hidden) {
@@ -209,6 +230,7 @@ void TileBasemap::fetchTile(int z, int x, int y, long long key) {
         if (!placed_.count(key) && reply->error() == QNetworkReply::NoError &&
             img.loadFromData(reply->readAll())) {
             placeTile(key, z, x, y, img);  // 仅新瓦片落地；其余(失败/已存在)只推动清理
+            if (kind_ == Satellite) fetchTerrain(z, x, y, key);  // 平面就位后拉 DEM 换起伏
         }
         purgeStale();  // 本块已解决 → 若整轮落地则清理被顶替的旧层
     });
@@ -256,4 +278,86 @@ void TileBasemap::placeTile(long long key, int z, int x, int y, const QImage& im
     if (rw_) rw_->Render();
 }
 
+void TileBasemap::fetchTerrain(int z, int x, int y, long long key) {
+    if (z > kDemMaxZoom) return;             // 高层级无 DEM → 维持平面
+    if (terrainInFlight_.count(key)) return;
+    const QString url =
+        QStringLiteral("http://s3.amazonaws.com/elevation-tiles-prod/terrarium/%1/%2/%3.png")
+            .arg(z)
+            .arg(x)
+            .arg(y);
+    const int gen = generation_;
+    terrainInFlight_.insert(key);
+    QNetworkReply* reply = nam_.get(QNetworkRequest(QUrl(url)));
+    connect(reply, &QNetworkReply::finished, this, [this, reply, key, z, x, y, gen]() {
+        reply->deleteLater();
+        terrainInFlight_.erase(key);
+        if (gen != generation_ || kind_ != Satellite) return;
+        if (placed_.find(key) == placed_.end()) return;  // 平面块已被清理
+        if (reply->error() != QNetworkReply::NoError) return;
+        QImage dem;
+        if (!dem.loadFromData(reply->readAll())) return;
+        applyTerrain(key, z, x, y, dem);
+    });
+}
+
+void TileBasemap::applyTerrain(long long key, int z, int x, int y, const QImage& dem) {
+    auto it = placed_.find(key);
+    if (it == placed_.end()) return;
+    vtkSmartPointer<vtkTexture> tex = it->second->GetTexture();  // 复用已贴卫星纹理
+    if (!tex) return;
+    if (!haveBaseline_) {  // 基准高程取首块中心 → 地形整体绕 z=0 起伏
+        baseline_ = demElev(dem, 0.5, 0.5);
+        haveBaseline_ = true;
+    }
+    auto warped = buildWarped(z, x, y, tex, dem);
+    scene_.renderer()->RemoveViewProp(it->second);
+    scene_.addActor(warped);
+    it->second = warped;
+    if (rw_) rw_->Render();
+}
+
+vtkSmartPointer<vtkActor> TileBasemap::buildWarped(int z, int x, int y,
+                                                   vtkSmartPointer<vtkTexture> tex,
+                                                   const QImage& dem) {
+    const geopro::render::LonLatBox b = geopro::render::tileBounds(z, x, y);
+    const auto sw = frame_->toLocal(b.south, b.west);
+    const auto se = frame_->toLocal(b.south, b.east);
+    const auto nw = frame_->toLocal(b.north, b.west);
+    const double base = kGroundZ + (z - kMinZoom) * kZEps;
+
+    // PlaneSource(等距圆柱下平面插值即正确 x/y) + 自动 tcoord；再按高程位移每点 Z。
+    vtkNew<vtkPlaneSource> plane;
+    plane->SetOrigin(sw.x, sw.y, base);
+    plane->SetPoint1(se.x, se.y, base);
+    plane->SetPoint2(nw.x, nw.y, base);
+    plane->SetResolution(kTerrainGrid, kTerrainGrid);
+    plane->Update();
+
+    auto warped = vtkSmartPointer<vtkPolyData>::New();
+    warped->DeepCopy(plane->GetOutput());
+    vtkDataArray* tc = warped->GetPointData()->GetTCoords();
+    vtkPoints* pts = warped->GetPoints();
+    const vtkIdType n = pts->GetNumberOfPoints();
+    for (vtkIdType id = 0; id < n; ++id) {
+        double t[2];
+        tc->GetTuple(id, t);
+        const double fx = t[0], fy = 1.0 - t[1];  // tcoord v: 南0北1 → fy: 北0南1(对齐 DEM 顶行=北)
+        const double elev = demElev(dem, fx, fy);
+        double p[3];
+        pts->GetPoint(id, p);
+        p[2] = base + (elev - baseline_) * kTerrainExag;
+        pts->SetPoint(id, p);
+    }
+    pts->Modified();
+
+    vtkNew<vtkPolyDataMapper> mapper;
+    mapper->SetInputData(warped);
+    auto actor = vtkSmartPointer<vtkActor>::New();
+    actor->SetMapper(mapper);
+    actor->SetTexture(tex);
+    actor->GetProperty()->LightingOff();
+    return actor;
+}
+
 }  // namespace geopro::app

src/app/TileBasemap.hpp

@@ -11,6 +11,7 @@
 
 class vtkActor;
 class vtkObject;
+class vtkTexture;
 class vtkRenderWindow;
 class vtkInteractorObserver;
 class vtkCallbackCommand;
@@ -41,6 +42,10 @@ private:
     bool computeView(double& centerLat, double& centerLon, int& zoom) const;
     void fetchTile(int z, int x, int y, long long key);
     void placeTile(long long key, int z, int x, int y, const QImage& img);
+    void fetchTerrain(int z, int x, int y, long long key);          // 拉对应 DEM 瓦片(卫星模式)
+    void applyTerrain(long long key, int z, int x, int y, const QImage& dem);  // 平面块换起伏块
+    vtkSmartPointer<vtkActor> buildWarped(int z, int x, int y, vtkSmartPointer<vtkTexture> tex,
+                                          const QImage& dem);  // DEM 位移网格 + 卫星贴图
     static void onInteractionEnd(vtkObject*, unsigned long, void* clientData, void*);
 
     geopro::render::Scene& scene_;
@@ -51,7 +56,10 @@ private:
     int generation_ = 0;                                    // show/hide/换源 自增，丢弃过期回包
     std::map<long long, vtkSmartPointer<vtkActor>> placed_;  // 已贴瓦片：key→actor
     std::set<long long> desired_;                           // 当前视野应显示的瓦片 key
-    std::set<long long> inFlight_;                          // 在途请求，避免重复拉
+    std::set<long long> inFlight_;                          // 卫星瓦片在途请求
+    std::set<long long> terrainInFlight_;                   // DEM 瓦片在途请求
+    double baseline_ = 0.0;                                 // 基准高程(首块中心)，地形绕 z=0 起伏
+    bool haveBaseline_ = false;
     vtkSmartPointer<vtkInteractorObserver> styleObs_;       // 持引用保证回调期有效
     vtkSmartPointer<vtkCallbackCommand> observer_;
     bool refreshing_ = false;