VTK/Examples/Cxx/GeometricObjects/OrientedArrow
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Jump to navigationJump to searchThis example illustrates how to create and display an arrow that passes through two points.
It demonstrates two different ways to apply the transform:
- Use vtkTransformPolyDataFilter to create a new transformed polydata. This method is useful if the transformed polydata is needed later in the pipeline, e.g. vtkGlyph3DFilter.
- Apply the transform directly to the actor using vtkProp3D's SetUserMatrix. No new data is produced.
Switch between the two methods by #defining USER_MATRIX or leaving out the #define.
NOTE: Compare this example with Oriented Cylinder . The transform is different because the cylinder height direction is along the y-axis and the arrow height is along the x axis.
Contents
OrientedArrow.cxx
#define USER_MATRIX
#include <vtkArrowSource.h>
#include <vtkPolyData.h>
#include <vtkSmartPointer.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkMath.h>
#include <vtkSphereSource.h>
#include <vtkProperty.h>
#include <vtkTransform.h>
#include <vtkTransformPolyDataFilter.h>
#include <time.h>
int main(int, char *[])
{
//Create an arrow.
vtkSmartPointer<vtkArrowSource> arrowSource =
vtkSmartPointer<vtkArrowSource>::New();
// Generate a random start and end point
double startPoint[3], endPoint[3];
#ifndef main
vtkMath::RandomSeed(time(NULL));
#else
vtkMath::RandomSeed(8775070);
#endif
startPoint[0] = vtkMath::Random(-10,10);
startPoint[1] = vtkMath::Random(-10,10);
startPoint[2] = vtkMath::Random(-10,10);
endPoint[0] = vtkMath::Random(-10,10);
endPoint[1] = vtkMath::Random(-10,10);
endPoint[2] = vtkMath::Random(-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];
arbitrary[0] = vtkMath::Random(-10,10);
arbitrary[1] = vtkMath::Random(-10,10);
arbitrary[2] = vtkMath::Random(-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 (unsigned int 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);
// Create spheres for start and end point
vtkSmartPointer<vtkSphereSource> sphereStartSource =
vtkSmartPointer<vtkSphereSource>::New();
sphereStartSource->SetCenter(startPoint);
vtkSmartPointer<vtkPolyDataMapper> sphereStartMapper =
vtkSmartPointer<vtkPolyDataMapper>::New();
sphereStartMapper->SetInputConnection(sphereStartSource->GetOutputPort());
vtkSmartPointer<vtkActor> sphereStart =
vtkSmartPointer<vtkActor>::New();
sphereStart->SetMapper(sphereStartMapper);
sphereStart->GetProperty()->SetColor(1.0, 1.0, .3);
vtkSmartPointer<vtkSphereSource> sphereEndSource =
vtkSmartPointer<vtkSphereSource>::New();
sphereEndSource->SetCenter(endPoint);
vtkSmartPointer<vtkPolyDataMapper> sphereEndMapper =
vtkSmartPointer<vtkPolyDataMapper>::New();
sphereEndMapper->SetInputConnection(sphereEndSource->GetOutputPort());
vtkSmartPointer<vtkActor> sphereEnd =
vtkSmartPointer<vtkActor>::New();
sphereEnd->SetMapper(sphereEndMapper);
sphereEnd->GetProperty()->SetColor(1.0, .3, .3);
//Create a renderer, render window, and interactor
vtkSmartPointer<vtkRenderer> renderer =
vtkSmartPointer<vtkRenderer>::New();
vtkSmartPointer<vtkRenderWindow> renderWindow =
vtkSmartPointer<vtkRenderWindow>::New();
renderWindow->AddRenderer(renderer);
vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
vtkSmartPointer<vtkRenderWindowInteractor>::New();
renderWindowInteractor->SetRenderWindow(renderWindow);
//Add the actor to the scene
renderer->AddActor(actor);
renderer->AddActor(sphereStart);
renderer->AddActor(sphereEnd);
renderer->SetBackground(.1, .2, .3); // Background color dark blue
//Render and interact
renderWindow->Render();
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
Please try the new VTKExamples website.
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(OrientedArrow)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(OrientedArrow MACOSX_BUNDLE OrientedArrow.cxx)
if(VTK_LIBRARIES)
target_link_libraries(OrientedArrow ${VTK_LIBRARIES})
else()
target_link_libraries(OrientedArrow vtkHybrid vtkWidgets)
endif()
Download and Build OrientedArrow
Click here to download OrientedArrow. and its CMakeLists.txt file.
Once the tarball OrientedArrow.tar has been downloaded and extracted,
cd OrientedArrow/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:
./OrientedArrow
WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.