spike(S3): VTK banded contour 管线跑通真实网格样本(图#18)

vtkImageData(规则栅格)->vtkDataSetSurfaceFilter->vtkBandedPolyDataContourFilter(GenerateContourEdges) 离屏渲染成功, 验证设计§4.3管线选型(B-1/B-2修正)。
颜色精确映射(colorBar非均匀值)留 render 层用 vtkColorTransferFunction 做。

tests/CMakeLists.txt

@@ -8,3 +8,5 @@ target_link_libraries(geopro_tests PRIVATE GTest::gtest GTest::gtest_main)
 
 include(GoogleTest)
 gtest_discover_tests(geopro_tests)
+
+add_subdirectory(spike)   # spike S3: banded contour 渲染验证

tests/spike/CMakeLists.txt

@@ -0,0 +1,15 @@
+# Spike S3: 真实样本 banded contour 离屏渲染（验证设计 §4.3 管线选型）
+find_package(nlohmann_json CONFIG REQUIRED)
+find_package(VTK REQUIRED COMPONENTS
+  CommonCore
+  CommonDataModel
+  CommonColor
+  FiltersGeometry
+  FiltersModeling
+  RenderingOpenGL2
+  IOImage
+)
+
+add_executable(grid_contour_spike grid_contour_spike.cpp)
+target_link_libraries(grid_contour_spike PRIVATE ${VTK_LIBRARIES} nlohmann_json::nlohmann_json)
+vtk_module_autoinit(TARGETS grid_contour_spike MODULES ${VTK_LIBRARIES})

tests/spike/grid_contour_spike.cpp

@@ -0,0 +1,141 @@
+// Spike S3: 用真实网格样本验证 VTK banded contour 管线（设计 §4.3 B-1/B-2 修正）。
+// vtkImageData(规则栅格) -> vtkDataSetSurfaceFilter -> vtkBandedPolyDataContourFilter
+//   (GenerateContourEdgesOn 同出 banded 面 + 等值线) -> 离屏渲染 PNG。
+// 目视对照 docs/_validate/ref_18_grid.png。
+//
+// 数据由 build 脚本拷成 ASCII 路径(Windows 下 ifstream 读中文路径会失败):
+//   D:/dev/spike_data/grid.json, colorbar.json -> spike_grid_contour.png
+#include <algorithm>
+#include <fstream>
+#include <string>
+#include <vector>
+
+#include <nlohmann/json.hpp>
+
+#include <vtkActor.h>
+#include <vtkBandedPolyDataContourFilter.h>
+#include <vtkCamera.h>
+#include <vtkDataSetSurfaceFilter.h>
+#include <vtkDoubleArray.h>
+#include <vtkImageData.h>
+#include <vtkLookupTable.h>
+#include <vtkNew.h>
+#include <vtkPNGWriter.h>
+#include <vtkPointData.h>
+#include <vtkPolyDataMapper.h>
+#include <vtkProperty.h>
+#include <vtkRenderWindow.h>
+#include <vtkRenderer.h>
+#include <vtkWindowToImageFilter.h>
+
+using json = nlohmann::json;
+
+static const std::string kDir = "D:/dev/spike_data/";
+
+struct Rgb { unsigned char r, g, b; };
+
+static Rgb parseHexOrRgb(const std::string& s) {
+    if (!s.empty() && s[0] == '#') {
+        auto h = [&](int i) { return (unsigned char)std::stoi(s.substr(i, 2), nullptr, 16); };
+        return Rgb{h(1), h(3), h(5)};
+    }
+    int r = 0, g = 0, b = 0;
+    auto p = s.find('(');
+    if (p != std::string::npos) std::sscanf(s.c_str() + p, "(%d,%d,%d", &r, &g, &b);
+    return Rgb{(unsigned char)r, (unsigned char)g, (unsigned char)b};
+}
+
+int main() {
+    // ---- 读网格 ----
+    json g = json::parse(std::ifstream(kDir + "grid.json"))["data"];
+    auto x = g["x"].get<std::vector<double>>();              // 100, 规则
+    auto y = g["y"].get<std::vector<double>>();              // 22, 规则
+    auto v = g["v"].get<std::vector<std::vector<double>>>(); // [22][100] = [j=y][i=x]
+    const int nx = (int)x.size(), ny = (int)y.size();
+    const double dx = x[1] - x[0], dy = y[1] - y[0];
+
+    vtkNew<vtkImageData> img;
+    img->SetDimensions(nx, ny, 1);
+    img->SetOrigin(x[0], y[0], 0.0);
+    img->SetSpacing(dx, dy, 1.0);
+    vtkNew<vtkDoubleArray> sc;
+    sc->SetName("v");
+    sc->SetNumberOfTuples((vtkIdType)nx * ny);
+    for (int j = 0; j < ny; ++j)
+        for (int i = 0; i < nx; ++i) sc->SetValue((vtkIdType)j * nx + i, v[j][i]);  // i 最快
+    img->GetPointData()->SetScalars(sc);
+
+    // ---- 色阶 stops ----
+    json cb = json::parse(std::ifstream(kDir + "colorbar.json"))["data"]["properties"]["colorBar"];
+    std::vector<std::pair<double, Rgb>> stops;
+    for (auto& pr : cb)
+        stops.emplace_back(std::stod(pr[0].get<std::string>()), parseHexOrRgb(pr[1].get<std::string>()));
+    std::sort(stops.begin(), stops.end(), [](auto& a, auto& b) { return a.first < b.first; });
+    const double vmin = stops.front().first, vmax = stops.back().first;
+
+    // 离散 LUT（阶梯，取下界）
+    vtkNew<vtkLookupTable> lut;
+    lut->SetNumberOfTableValues((vtkIdType)stops.size());
+    lut->SetTableRange(vmin, vmax);
+    for (size_t k = 0; k < stops.size(); ++k) {
+        auto c = stops[k].second;
+        lut->SetTableValue((vtkIdType)k, c.r / 255.0, c.g / 255.0, c.b / 255.0, 1.0);
+    }
+    lut->Build();
+
+    // ---- 管线：imageData -> surface(polydata) -> banded contour(+edges) ----
+    vtkNew<vtkDataSetSurfaceFilter> surf;
+    surf->SetInputData(img);
+
+    vtkNew<vtkBandedPolyDataContourFilter> banded;
+    banded->SetInputConnection(surf->GetOutputPort());
+    std::vector<double> levels;
+    for (auto& s : stops) levels.push_back(s.first);
+    banded->SetNumberOfContours((int)levels.size());
+    for (int k = 0; k < (int)levels.size(); ++k) banded->SetValue(k, levels[k]);
+    banded->GenerateContourEdgesOn();
+    banded->SetScalarModeToValue();
+
+    vtkNew<vtkPolyDataMapper> mapper;
+    mapper->SetInputConnection(banded->GetOutputPort());
+    mapper->SetScalarModeToUseCellData();
+    mapper->SetLookupTable(lut);
+    mapper->SetScalarRange(vmin, vmax);
+
+    vtkNew<vtkActor> bands;
+    bands->SetMapper(mapper);
+
+    // 等值线边（黑）
+    vtkNew<vtkPolyDataMapper> edgeMapper;
+    edgeMapper->SetInputConnection(banded->GetOutputPort(1));  // contour edges
+    edgeMapper->ScalarVisibilityOff();
+    vtkNew<vtkActor> edges;
+    edges->SetMapper(edgeMapper);
+    edges->GetProperty()->SetColor(0, 0, 0);
+    edges->GetProperty()->SetLineWidth(0.5);
+
+    // ---- 离屏渲染 ----
+    vtkNew<vtkRenderer> ren;
+    ren->AddActor(bands);
+    ren->AddActor(edges);
+    ren->SetBackground(1, 1, 1);
+    ren->GetActiveCamera()->ParallelProjectionOn();
+    ren->ResetCamera();
+
+    vtkNew<vtkRenderWindow> rw;
+    rw->SetOffScreenRendering(1);
+    rw->AddRenderer(ren);
+    rw->SetSize(1100, 320);
+    rw->Render();
+
+    vtkNew<vtkWindowToImageFilter> w2i;
+    w2i->SetInput(rw);
+    vtkNew<vtkPNGWriter> png;
+    png->SetFileName((kDir + "spike_grid_contour.png").c_str());
+    png->SetInputConnection(w2i->GetOutputPort());
+    png->Write();
+
+    std::printf("SPIKE_S3_DONE grid=%dx%d stops=%zu vmin=%.1f vmax=%.1f\n", nx, ny, stops.size(),
+                vmin, vmax);
+    return 0;
+}

vcpkg.json

@@ -3,6 +3,7 @@
   "version": "0.1.0",
   "description": "Geopro 3.0 desktop client (Qt6 + VTK9) - M1. 方案②-修订: Qt/VTK/ADS/QtKeychain 对接官方 MSVC Qt(不走 vcpkg); 仅非 Qt 依赖走 vcpkg, 按层递增。",
   "dependencies": [
-    "gtest"
+    "gtest",
+    "nlohmann-json"
   ]
 }