VTK 模型的颜色映射

#include <vtkActor.h>
#include <vtkFloatArray.h>
#include <vtkLookupTable.h>
#include <vtkPointData.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkSmartPointer.h>
#include <vtkSTLReader.h>
#include <vtkInteractorStyleTrackballCamera.h>
 
#include <vtkAutoInit.h> 
VTK_MODULE_INIT(vtkRenderingOpenGL2);
VTK_MODULE_INIT(vtkInteractionStyle);
VTK_MODULE_INIT(vtkRenderingVolumeOpenGL2);
VTK_MODULE_INIT(vtkRenderingFreeType);
 
int main(int, char* [])
{
    // 加载一个J20的STL模型
    vtkSmartPointer<vtkSTLReader> source = vtkSmartPointer<vtkSTLReader>::New();
    source->SetFileName("C:\\Users\\wangjun\\3D Objects\\J20.stl");
    source->Update();
 
    int numPts = source->GetOutput()->GetPoints()->GetNumberOfPoints();                    // 获取模型的顶点数量
    vtkSmartPointer<vtkFloatArray> scalars = vtkSmartPointer<vtkFloatArray>::New();        // 创建存储顶点属性的float数组
    scalars->SetNumberOfValues(numPts);
    for (int i = 0; i < numPts; ++i)        // 为属性数组中的每个元素设置标量值（这个标量值可以当作颜色值）
        scalars->SetValue(i, i);
 
    vtkSmartPointer<vtkPolyData> poly = vtkSmartPointer<vtkPolyData>::New();
    poly->DeepCopy(source->GetOutput());
    poly->GetPointData()->SetScalars(scalars);
 
    // 创建颜色查找表
    vtkSmartPointer<vtkLookupTable> hueLut = vtkSmartPointer<vtkLookupTable>::New();
    hueLut->SetNumberOfColors(numPts);        // 指定颜色查找表中有多少种颜色
    hueLut->SetHueRange(0.67, 0.0);            // 设定HSV颜色范围，色调H取值范围为0°～360°，从红色开始按逆时针方向计算，红色为0°/0.0，绿色为120°/0.34,蓝色为240°/0.67
    hueLut->Build();
 
    vtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
    mapper->SetInputData(poly);
    mapper->SetScalarRange(0, numPts);            // 设置标量值的范围
    mapper->ScalarVisibilityOn();
    //mapper->SetColorModeToMapScalars();        // 无论变量数据是何种类型，该方法都通过查询表对标量数据进行映射
    mapper->SetColorModeToDefault();            // 默认的映射器行为，即把unsigned char类型的标量属性数据当作颜色值，不执行隐式。对于其他类型的标量数据，将通过查询表映射。
    mapper->SetLookupTable(hueLut);
 
    vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
    actor->SetMapper(mapper);
 
    vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
    renderer->GradientBackgroundOn();
    renderer->SetBackground(1, 1, 1);
    renderer->SetBackground2(0, 0, 0);
 
    vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
    renderWindow->AddRenderer(renderer);
 
    vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New();
    renderWindowInteractor->SetRenderWindow(renderWindow);
    vtkSmartPointer<vtkInteractorStyleTrackballCamera> style = vtkSmartPointer<vtkInteractorStyleTrackballCamera>::New();
    renderWindowInteractor->SetInteractorStyle(style);
 
    renderer->AddActor(actor);
    renderWindow->SetSize(600, 600);
    renderWindow->Render();
    renderWindowInteractor->Start();
 
    return 0;
}