VTK 9.5.1 で .vtkhdf 形式でファイル保存/読み込み(vtkMultiBlockDataSet)

#pragma once

#include "createpoly.hpp"

#include <vtkDataArraySelection.h>


/////////////////////////////////////////
/////////////////////////////////////////
// 保存コード
/////////////////////////////////////////
/////////////////////////////////////////

void save_as_Multiblock() {

    vtkSmartPointer<vtkPolyData> polypoints = createPoints();
    vtkSmartPointer<vtkPolyData> polycone = createCone();
    vtkSmartPointer<vtkPolyData> polyline = createPolyLine();

    auto mb = vtkSmartPointer<vtkMultiBlockDataSet>::New();
    mb->SetNumberOfBlocks(3);

    mb->SetBlock(0, polypoints);
    mb->SetBlock(1, polycone);
    mb->SetBlock(2, polyline);

    auto w = vtkSmartPointer<vtkHDFWriter>::New();
    w->SetInputData(mb);
    w->SetFileName("scene.vtkhdf");
    w->Write();

}

/////////////////////////////////////////
/////////////////////////////////////////
// 読み込みコード
/////////////////////////////////////////
/////////////////////////////////////////

std::vector< vtkSmartPointer<vtkPolyData> > load_as_Multiblock() {

    std::vector< vtkSmartPointer<vtkPolyData> > polyvec;


    auto reader = vtkSmartPointer<vtkHDFReader>::New();
    reader->SetFileName("scene.vtkhdf");

    reader->GetPointDataArraySelection()->EnableAllArrays();
    reader->GetCellDataArraySelection()->EnableAllArrays();

    reader->Update();

    //vtkDataObject* out = reader->GetOutput();
    vtkDataObject* out = reader->GetOutputDataObject(0);
    auto mb = vtkMultiBlockDataSet::SafeDownCast(out);

    std::cout << "MultiBlock with " << mb->GetNumberOfBlocks() << " blocks\n";

	// 各ブロックを処理
    for (unsigned int i = 0; i < mb->GetNumberOfBlocks(); i++) {

        vtkPolyData* poly = vtkPolyData::SafeDownCast(mb->GetBlock(i));

        if (poly) {

            // RGB配列があればアクティブにする例
            if (poly->GetPointData()->HasArray("RGB")) {
                poly->GetPointData()->SetActiveScalars("RGB");
            }

        }

        polyvec.push_back(poly);
    }


    return polyvec;
}

#pragma once

#include <vtkSmartPointer.h>

#include <vtkDoubleArray.h>
#include <vtkPointData.h>

#include <vtkConeSource.h>

#include <vtkCellArray.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>

#include <vtkUnsignedCharArray.h>
#include <array>

#include <vtkCellData.h>
 

vtkSmartPointer<vtkPolyData> createPoints() {

    // 頂点配列
    vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();

    // 色情報の配列
    vtkSmartPointer<vtkUnsignedCharArray> colors = vtkSmartPointer<vtkUnsignedCharArray>::New();
    colors->SetNumberOfComponents(3);
    colors->SetName("RGB");

    // 頂点インデクスの配列
    vtkSmartPointer<vtkCellArray> cells = vtkSmartPointer<vtkCellArray>::New();



    for (size_t i = 0; i < 100000; i++) {

        double x = (double)rand() / (double)RAND_MAX;
        double y = (double)rand() / (double)RAND_MAX;
        double z = (double)rand() / (double)RAND_MAX;

        points->InsertNextPoint(x, y, z);  // 座標追加

        unsigned char r = static_cast<unsigned char>(x * 255.0);
        unsigned char g = static_cast<unsigned char>(y * 255.0);
        unsigned char b = static_cast<unsigned char>(z * 255.0);
        colors->InsertNextTypedTuple(std::array<unsigned char, 3>{r, g, b}.data());

        cells->InsertNextCell(1);  // 要素数
        cells->InsertCellPoint(i); // 頂点インデックスを追加

    }

    // --- vtkPolyData作成 ---
    auto polydata = vtkSmartPointer<vtkPolyData>::New();
    polydata->SetPoints(points);
    polydata->SetVerts(cells);
    polydata->GetPointData()->SetScalars(colors);
    polydata->GetPointData()->SetActiveScalars("RGB");

    return polydata;
}

vtkSmartPointer<vtkPolyData> createCone() {
    vtkSmartPointer<vtkConeSource> coneSource;
    coneSource = vtkSmartPointer<vtkConeSource>::New();
    coneSource->SetHeight(1.0);
    coneSource->SetRadius(0.2);
    coneSource->SetResolution(10);
    coneSource->Update();
    vtkSmartPointer<vtkPolyData> conePolyData = coneSource->GetOutput();
    return conePolyData;
}

vtkSmartPointer<vtkPolyData> createPolyLine() {

    // VTKのデータ構造で W の形状を作成
    // 頂点配列
    vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();
    // 色情報の配列
    vtkSmartPointer<vtkUnsignedCharArray> colors = vtkSmartPointer<vtkUnsignedCharArray>::New();
    colors->SetNumberOfComponents(3);
    colors->SetName("RGB");

    // 頂点インデクスの配列
    vtkSmartPointer<vtkCellArray> cells = vtkSmartPointer<vtkCellArray>::New();
    // 頂点追加
    points->InsertNextPoint(0.0, 0.0, 0.0);  // 0
    colors->InsertNextTypedTuple(std::array<unsigned char, 3>{255,0,0}.data());


    points->InsertNextPoint(0.5, 1.0, 0.0);  // 1
    colors->InsertNextTypedTuple(std::array<unsigned char, 3>{0,255, 0}.data());

    points->InsertNextPoint(1.0, 0.0, 0.0);  // 2
    colors->InsertNextTuple3(0.0, 0.0, 1.0);
    colors->InsertNextTypedTuple(std::array<unsigned char, 3>{0, 0, 255}.data());

    points->InsertNextPoint(1.5, 1.0, 0.0);  // 3
    colors->InsertNextTypedTuple(std::array<unsigned char, 3>{255, 255, 0}.data());

    points->InsertNextPoint(2.0, 0.0, 0.0);  // 4
    colors->InsertNextTypedTuple(std::array<unsigned char, 3>{255, 0, 255}.data());

    // 頂点インデクス追加
    cells->InsertNextCell(5); // 要素数
    cells->InsertCellPoint(0);
    cells->InsertCellPoint(1);
    cells->InsertCellPoint(2);
    cells->InsertCellPoint(3);
    cells->InsertCellPoint(4);
    // --- vtkPolyData作成 ---
    auto polydata = vtkSmartPointer<vtkPolyData>::New();
    polydata->SetPoints(points);
    polydata->SetLines(cells);
    polydata->GetPointData()->SetScalars(colors);


    return polydata;

}