1.在VTK自带的vtkStructuredGrid数据文件combq.bin和combxyz.bin

2.文件读取代码如下：

//读取数据文件
    Create(vtkMultiBlockPLOT3DReader, reader);
    reader->SetXYZFileName("G:/Temp/vtkTest/combxyz.bin");
    reader->SetQFileName("G:/Temp/vtkTest/combq.bin");
    reader->SetScalarFunctionNumber(100);//100代表密度数据
    reader->SetVectorFunctionNumber(202);//202代表冲量数据
    reader->Update();

    vtkStructuredGrid *object = (vtkStructuredGrid *)reader->GetOutput()->GetBlock(0);

3.获得一个vtkStructuredGrid数据，带有标量数据和矢量数据，下面的代码提取一个维度面

//提取面
    Create(vtkStructuredGridGeometryFilter, plane);
    plane->SetInputData(object);
    plane->SetExtent(0, 100, 0, 100, 7, 7);

数据的实际维度是57 33 2，可以用下面的代码查看

int extends[6]={0};
    object->GetExtent(extends);

这里维度0 100 0 100 7 7，表示提取Z维度7这个面，XY维度数据设置大了没事，会自动裁剪。对于不知道数据维度的数据，就要设置一个大点的值。从下图可以明显看出Z维度7的含义。

4.将从文件中提取的数据保存到txt文件中，观察一下数据有哪些

Create(vtkStructuredGridWriter,writer);
    writer->SetInputData(object);
    writer->SetFileName("data.txt");
    writer->Write();

4.1 文件开头如下，数据点的数据量就是维数的乘积。

4.2 搜索 POINT_DATA来到点数据

4.3 简单计算一下就能明白上面是数据点位，下面是数据标量值。

5.完整代码，数据文件已绑定上传

#include<vtkProperty.h>
#include<vtkAxesActor.h>
#include<vtkLookupTable.h>
#include<vtkDataSetMapper.h>
#include<vtkStructuredGrid.h>
#include<vtkMultiBlockDataSet.h>
#include<vtkStructuredGridWriter.h>
#include<vtkMultiBlockPLOT3DReader.h>
#include<vtkOrientationMarkerWidget.h>
#include<vtkStructuredGridGeometryFilter.h>

#include<vtkNew.h>
#include<vtkRenderer.h>
#include<vtkAutoInit.h>
#include<vtkRenderWindow.h>
#include<vtkPolyDataMapper.h>
#include<vtkRenderWindowInteractor.h>

VTK_MODULE_INIT(vtkRenderingOpenGL2)
VTK_MODULE_INIT(vtkInteractionStyle)
VTK_MODULE_INIT(vtkRenderingFreeType)


#define Create(type,name)    vtkNew<type> name

int main()
{
    //读取数据文件
    Create(vtkMultiBlockPLOT3DReader, reader);
    reader->SetXYZFileName("G:/Temp/vtkTest/combxyz.bin");
    reader->SetQFileName("G:/Temp/vtkTest/combq.bin");
    reader->SetScalarFunctionNumber(100);//100代表密度数据
    reader->SetVectorFunctionNumber(202);//202代表冲量数据
    reader->Update();

    vtkStructuredGrid *object = (vtkStructuredGrid *)reader->GetOutput()->GetBlock(0);

    Create(vtkStructuredGridWriter, writer);
    writer->SetInputData(object);
    writer->SetFileName("data.txt");
    writer->Write();

    int extends[6] = {0};
    object->GetExtent(extends);

    //提取面
    Create(vtkStructuredGridGeometryFilter, plane);
    plane->SetInputData(object);
    plane->SetExtent(0, 100, 0, 100, 7, 7);

    //默认的颜色表
    Create(vtkLookupTable, look);
    look->SetNumberOfColors(256);
    look->Build();

    //可视化面
    Create(vtkPolyDataMapper, planeMapper);
    planeMapper->SetLookupTable(look);
    planeMapper->SetInputConnection(plane->GetOutputPort());
    planeMapper->SetScalarRange(object->GetScalarRange());

    Create(vtkActor, planeActor);
    planeActor->SetMapper(planeMapper);

    //可视化整个数据
    Create(vtkDataSetMapper, gridMapper);
    gridMapper->SetInputData(object);
    Create(vtkActor, gridActor);
    gridActor->SetMapper(gridMapper);
    gridActor->GetProperty()->SetEdgeVisibility(true);
    gridActor->GetProperty()->SetRepresentationToWireframe();



    Create(vtkRenderer, render);
    render->AddActor(planeActor);
    render->AddActor(gridActor);


    Create(vtkRenderWindow, window);
    window->AddRenderer(render);

    Create(vtkRenderWindowInteractor, inter);
    inter->SetRenderWindow(window);

    //坐标系显示
    Create(vtkAxesActor, axes);
    Create(vtkOrientationMarkerWidget, widget);
    widget->SetOrientationMarker(axes);
    widget->SetInteractor(inter);
    widget->SetEnabled(true);
    widget->InteractiveOn();


    render->ResetCamera();

    inter->Start();
    return 0;
}