TriangleSolidColor

#include <vtkActor.h>
#include <vtkCellArray.h>
#include <vtkCellData.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkTriangle.h>
#include <vtkUnsignedCharArray.h>
#include <vtkXMLPolyDataWriter.h>

// For compatibility with new VTK generic data arrays
#ifdef vtkGenericDataArray_h
#define InsertNextTupleValue InsertNextTypedTuple
#endif

int main(int, char*[])
{
  // Setup points
  auto points = vtkSmartPointer<vtkPoints>::New();
  //auto vertices = vtkSmartPointer<vtkCellArray>::New();
  points->InsertNextPoint(0.0, 0.0, 0.0);
  points->InsertNextPoint(1.0, 0.0, 0.0);
  points->InsertNextPoint(0.0, 1.0, 0.0);

  // Setup colors
  unsigned char red[3]{255, 0, 0};

  auto colors = vtkSmartPointer<vtkUnsignedCharArray>::New();
  colors->SetNumberOfComponents(3);
  colors->SetName("Colors");
  colors->InsertNextTupleValue(red);

  auto triangles = vtkSmartPointer<vtkCellArray>::New();
  auto triangle = vtkSmartPointer<vtkTriangle>::New();
  triangle->GetPointIds()->SetId(0, 0);
  triangle->GetPointIds()->SetId(1, 1);
  triangle->GetPointIds()->SetId(2, 2);
  triangles->InsertNextCell(triangle);

  auto polydata = vtkSmartPointer<vtkPolyData>::New();

  polydata->SetPoints(points);
  polydata->SetPolys(triangles);
  polydata->GetCellData()->SetScalars(colors);

  // Visualize
  auto mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
  mapper->SetInputData(polydata);

  auto actor = vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);

  auto renderer = vtkSmartPointer<vtkRenderer>::New();
  auto renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  auto renderWindowInteractor =
      vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);

  renderer->AddActor(actor);
  renderer->ResetCamera();

  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(TriangleSolidColor)

find_package(VTK COMPONENTS 
  vtkvtkCommonCore
  vtkvtkCommonDataModel
  vtkvtkIOXML
  vtkvtkInteractionStyle
  vtkvtkRenderingContextOpenGL2
  vtkvtkRenderingCore
  vtkvtkRenderingFreeType
  vtkvtkRenderingGL2PSOpenGL2
  vtkvtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
  message("Skipping TriangleSolidColor: ${VTK_NOT_FOUND_MESSAGE}")
  return ()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
  # old system
  include(${VTK_USE_FILE})
  add_executable(TriangleSolidColor MACOSX_BUNDLE TriangleSolidColor.cxx )
  target_link_libraries(TriangleSolidColor PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(TriangleSolidColor MACOSX_BUNDLE TriangleSolidColor.cxx )
  target_link_libraries(TriangleSolidColor PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS TriangleSolidColor
    MODULES ${VTK_LIBRARIES}
    )
endif ()

cd TriangleSolidColor/build

cmake ..

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

make

./TriangleSolidColor