# ProgrammableSource

VTKExamples/Cxx/Filtering/ProgrammableSource

### Description¶

Use a programmable source to generate the points for the Lorenz System

Question

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### Code¶

ProgrammableSource.cxx

#include <vtkSmartPointer.h>
#include <vtkProgrammableSource.h>
#include <vtkPolyData.h>
#include <vtkVertexGlyphFilter.h>
#include <vtkPoints.h>

#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>

// https://en.wikipedia.org/wiki/Lorenz_system
static void Lorenz(void *arg)
{
double sigma = 10.0;  /* The Lorenz paramaters */
double beta = 8.0 / 3.0;
double rho = 28.0;
double h = .001;      /* Integration step size */

double x, y, z;
double xx, yy, zz;
x = 0.1;
y = 0.1;
z = 0.1;
vtkSmartPointer<vtkPoints> points =
vtkSmartPointer<vtkPoints>::New();
// Get to a stable starting point
for (int i = 0; i < 1000; ++i)
{
xx = x + h * sigma * (y - x);
yy = y + h * (x * (rho - z) - y);
zz = z + h * (x * y - (beta * z));
x = xx; y = yy; z = zz;
}
for (int i = 0; i < 500000; ++i)
{
xx = x + h * sigma * (y - x);
yy = y + h * (x * (rho - z) - y);
zz = z + h * (x * y - (beta * z));
points->InsertNextPoint(xx, yy, zz);
x = xx; y = yy; z = zz;
}
vtkSmartPointer<vtkPolyData> pointsPolydata =
vtkSmartPointer<vtkPolyData>::New();
pointsPolydata->SetPoints(points);
vtkSmartPointer<vtkVertexGlyphFilter> vertexFilter =
vtkSmartPointer<vtkVertexGlyphFilter>::New();
vertexFilter->SetInputData(pointsPolydata);
vertexFilter->Update();
vtkProgrammableSource * ps =
static_cast<vtkProgrammableSource *>(arg);
vtkPolyData *output = ps->GetPolyDataOutput();
output->DeepCopy(vertexFilter->GetOutput());
}

int main (int, char *[])
{
vtkSmartPointer<vtkProgrammableSource> source =
vtkSmartPointer<vtkProgrammableSource>::New();
source->SetExecuteMethod(Lorenz, source);
source->Update();

vtkSmartPointer<vtkPolyDataMapper> mapper =
vtkSmartPointer<vtkPolyDataMapper>::New();
mapper->SetInputData(source->GetPolyDataOutput());

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

// Setup render window, renderer, 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);
renderer->AddActor(actor);
renderer->SetBackground(.4, .5, .7);
renderWindow->Render();
renderWindowInteractor->Start();

return EXIT_SUCCESS;
}


### CMakeLists.txt¶

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(ProgrammableSource)

find_package(VTK COMPONENTS
vtkCommonCore
vtkCommonDataModel
vtkFiltersGeneral
vtkFiltersSources
vtkInteractionStyle
vtkRenderingCore
vtkRenderingFreeType
vtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
message("Skipping ProgrammableSource: ${VTK_NOT_FOUND_MESSAGE}") return () endif() message (STATUS "VTK_VERSION:${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
# old system
include(${VTK_USE_FILE}) add_executable(ProgrammableSource MACOSX_BUNDLE ProgrammableSource.cxx ) target_link_libraries(ProgrammableSource PRIVATE${VTK_LIBRARIES})
else ()
# include all components
add_executable(ProgrammableSource MACOSX_BUNDLE ProgrammableSource.cxx )
target_link_libraries(ProgrammableSource PRIVATE ${VTK_LIBRARIES}) # vtk_module_autoinit is needed vtk_module_autoinit( TARGETS ProgrammableSource MODULES${VTK_LIBRARIES}
)
endif ()


### Download and Build ProgrammableSource¶

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

cd ProgrammableSource/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:

./ProgrammableSource


WINDOWS USERS

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