88 lines
2.5 KiB
C++
88 lines
2.5 KiB
C++
#include "actors/ScatterActor.hpp"
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#include <cstddef>
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#include <vector>
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#include <vtkCellArray.h>
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#include <vtkDoubleArray.h>
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#include <vtkNew.h>
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#include <vtkPointData.h>
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#include <vtkPoints.h>
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#include <vtkPolyData.h>
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#include <vtkPolyDataMapper.h>
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#include <vtkProperty.h>
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#include "ColorLutBuilder.hpp"
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namespace geopro::render {
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namespace {
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// LUT 级数。
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constexpr int kLutLevels = 256;
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} // namespace
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vtkSmartPointer<vtkActor> buildScatter(const geopro::core::ScatterField& s,
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const geopro::core::ColorScale& cs,
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float pointSize)
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{
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const std::size_t n = s.v.size();
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// 退化输入：无值或 x/y 长度不足 → 空 actor(调用方仍可安全 add，mapper 无输入则不绘制)。
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if (n == 0 || s.x.size() < n || s.y.size() < n) {
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return vtkSmartPointer<vtkActor>::New();
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}
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vtkNew<vtkPoints> points;
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points->SetNumberOfPoints(static_cast<vtkIdType>(n));
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vtkNew<vtkCellArray> verts; // 每点一个 vtkVertex(GL_POINTS)，渲染为方块点
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vtkNew<vtkDoubleArray> sc;
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sc->SetName("v");
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sc->SetNumberOfTuples(static_cast<vtkIdType>(n));
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for (std::size_t i = 0; i < n; ++i) {
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const auto id = static_cast<vtkIdType>(i);
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// y=深度(越大越深)→取负，使深部在下、剖面不倒置(与 GridContourActor 一致)。
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points->SetPoint(id, s.x[i], -s.y[i], 0.0);
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verts->InsertNextCell(1, &id);
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sc->SetValue(id, s.v[i]);
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}
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vtkNew<vtkPolyData> poly;
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poly->SetPoints(points);
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poly->SetVerts(verts);
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poly->GetPointData()->SetScalars(sc);
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// 色阶范围：优先 colorBar 真实分段值(非均匀)，否则回退到 v 实测范围。
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const std::vector<double> stops = cs.stopValues();
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double vmin, vmax;
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if (stops.size() >= 2) {
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vmin = stops.front();
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vmax = stops.back();
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} else {
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vmin = s.v.front();
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vmax = vmin;
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for (double v : s.v) {
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if (v < vmin) vmin = v;
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if (v > vmax) vmax = v;
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}
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if (vmin >= vmax) vmax = vmin + 1.0;
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}
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auto lut = buildLut(cs, vmin, vmax, kLutLevels);
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vtkNew<vtkPolyDataMapper> mapper;
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mapper->SetInputData(poly);
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mapper->SetScalarModeToUsePointData();
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mapper->SetLookupTable(lut);
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mapper->SetScalarRange(vmin, vmax);
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auto actor = vtkSmartPointer<vtkActor>::New();
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actor->SetMapper(mapper);
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actor->GetProperty()->SetPointSize(pointSize);
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return actor;
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}
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} // namespace geopro::render
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