OpenVROrientedArrow

VTKExamples/Cxx/GeometricObjects/OpenVROrientedArrow


VTK + OpenVR OrientedArrow example.

Question

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Code

OpenVROrientedArrow.cxx

#include <vtkActor.h>
#include <vtkArrowSource.h>
#include <vtkMath.h>
#include <vtkMinimalStandardRandomSequence.h>
#include <vtkNamedColors.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkOpenVRRenderWindow.h>
#include <vtkOpenVRRenderWindowInteractor.h>
#include <vtkOpenVRRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>
#include <vtkTransform.h>
#include <vtkTransformPolyDataFilter.h>
#include <array>
#define USER_MATRIX

int main(int, char *[])
{
  vtkSmartPointer<vtkNamedColors> colors =
    vtkSmartPointer<vtkNamedColors>::New();

  // Set the background color.
  std::array<unsigned char, 4> bkg{ { 26, 51, 77, 255 } };
  colors->SetColor("BkgColor", bkg.data());

  //Create an arrow.
  vtkSmartPointer<vtkArrowSource> arrowSource =
    vtkSmartPointer<vtkArrowSource>::New();

  // Generate a random start and end point
  double startPoint[3];
  double endPoint[3];
  vtkSmartPointer<vtkMinimalStandardRandomSequence> rng =
    vtkSmartPointer<vtkMinimalStandardRandomSequence>::New();
  rng->SetSeed(8775070); // For testing.
  for (auto i = 0; i < 3; ++i)
  {
    rng->Next();
    startPoint[i] = rng->GetRangeValue(-10, 10);
    rng->Next();
    endPoint[i] = rng->GetRangeValue(-10, 10);
  }

  // Compute a basis
  double normalizedX[3];
  double normalizedY[3];
  double normalizedZ[3];

  // The X axis is a vector from start to end
  vtkMath::Subtract(endPoint, startPoint, normalizedX);
  double length = vtkMath::Norm(normalizedX);
  vtkMath::Normalize(normalizedX);

  // The Z axis is an arbitrary vector cross X
  double arbitrary[3];
  for (auto i = 0; i < 3; ++i)
  {
    rng->Next();
    arbitrary[i] = rng->GetRangeValue(-10, 10);
  }
  vtkMath::Cross(normalizedX, arbitrary, normalizedZ);
  vtkMath::Normalize(normalizedZ);

  // The Y axis is Z cross X
  vtkMath::Cross(normalizedZ, normalizedX, normalizedY);
  vtkSmartPointer<vtkMatrix4x4> matrix =
    vtkSmartPointer<vtkMatrix4x4>::New();

  // Create the direction cosine matrix
  matrix->Identity();
  for (auto i = 0; i < 3; i++)
  {
    matrix->SetElement(i, 0, normalizedX[i]);
    matrix->SetElement(i, 1, normalizedY[i]);
    matrix->SetElement(i, 2, normalizedZ[i]);
  }

  // Apply the transforms
  vtkSmartPointer<vtkTransform> transform =
    vtkSmartPointer<vtkTransform>::New();
  transform->Translate(startPoint);
  transform->Concatenate(matrix);
  transform->Scale(length, length, length);

  // Transform the polydata
  vtkSmartPointer<vtkTransformPolyDataFilter> transformPD =
    vtkSmartPointer<vtkTransformPolyDataFilter>::New();
  transformPD->SetTransform(transform);
  transformPD->SetInputConnection(arrowSource->GetOutputPort());

  //Create a mapper and actor for the arrow
  vtkSmartPointer<vtkPolyDataMapper> mapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  vtkSmartPointer<vtkActor> actor =
    vtkSmartPointer<vtkActor>::New();
#ifdef USER_MATRIX
  mapper->SetInputConnection(arrowSource->GetOutputPort());
  actor->SetUserMatrix(transform->GetMatrix());
#else
  mapper->SetInputConnection(transformPD->GetOutputPort());
#endif
  actor->SetMapper(mapper);
  actor->GetProperty()->SetColor(colors->GetColor3d("Cyan").GetData());

  // Create spheres for start and end point
  vtkSmartPointer<vtkSphereSource> sphereStartSource =
    vtkSmartPointer<vtkSphereSource>::New();
  sphereStartSource->SetCenter(startPoint);
  sphereStartSource->SetRadius(0.8);
  vtkSmartPointer<vtkPolyDataMapper> sphereStartMapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  sphereStartMapper->SetInputConnection(sphereStartSource->GetOutputPort());
  vtkSmartPointer<vtkActor> sphereStart =
    vtkSmartPointer<vtkActor>::New();
  sphereStart->SetMapper(sphereStartMapper);
  sphereStart->GetProperty()->SetColor(colors->GetColor3d("Yellow").GetData());

  vtkSmartPointer<vtkSphereSource> sphereEndSource =
    vtkSmartPointer<vtkSphereSource>::New();
  sphereEndSource->SetCenter(endPoint);
  sphereEndSource->SetRadius(0.8);
  vtkSmartPointer<vtkPolyDataMapper> sphereEndMapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  sphereEndMapper->SetInputConnection(sphereEndSource->GetOutputPort());
  vtkSmartPointer<vtkActor> sphereEnd =
    vtkSmartPointer<vtkActor>::New();
  sphereEnd->SetMapper(sphereEndMapper);
  sphereEnd->GetProperty()->SetColor(colors->GetColor3d("Magenta").GetData());

  //Create a renderer, render window, and interactor
  vtkSmartPointer<vtkOpenVRRenderer> renderer =
    vtkSmartPointer<vtkOpenVRRenderer>::New();
  vtkSmartPointer<vtkOpenVRRenderWindow> renderWindow =
    vtkSmartPointer<vtkOpenVRRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  vtkSmartPointer<vtkOpenVRRenderWindowInteractor> renderWindowInteractor =
    vtkSmartPointer<vtkOpenVRRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);

  //Add the actor to the scene
  renderer->AddActor(actor);
  renderer->AddActor(sphereStart);
  renderer->AddActor(sphereEnd);
  renderer->SetBackground(colors->GetColor3d("BkgColor").GetData());

  //Render and interact
  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(OpenVROrientedArrow)

find_package(VTK COMPONENTS 
  vtkCommonColor
  vtkCommonCore
  vtkCommonDataModel
  vtkCommonTransforms
  vtkFiltersGeneral
  vtkFiltersSources
  vtkInteractionStyle
  vtkRenderingCore
  vtkRenderingFreeType
  vtkRenderingOpenGL2
  vtkRenderingOpenVR QUIET)
if (NOT VTK_FOUND)
  message("Skipping OpenVROrientedArrow: ${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(OpenVROrientedArrow MACOSX_BUNDLE OpenVROrientedArrow.cxx )
  target_link_libraries(OpenVROrientedArrow PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(OpenVROrientedArrow MACOSX_BUNDLE OpenVROrientedArrow.cxx )
  target_link_libraries(OpenVROrientedArrow PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS OpenVROrientedArrow
    MODULES ${VTK_LIBRARIES}
    )
endif () 

Download and Build OpenVROrientedArrow

Click here to download OpenVROrientedArrow and its CMakeLists.txt file. Once the tarball OpenVROrientedArrow.tar has been downloaded and extracted,

cd OpenVROrientedArrow/build 

If VTK is installed:

cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

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

Build the project:

make

and run it:

./OpenVROrientedArrow

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.