QuadricDecimation
VTKExamples/Cxx/Meshes/QuadricDecimation
Description¶
This example uses Quadric Clustering, based on the work of Garland and Heckbert who first presented the quadric error measure at Siggraph '97 "Surface Simplification Using Quadric Error Metrics". For details of the algorithm Michael Garland's Ph.D. thesis is also recommended. Hughues Hoppe's Vis '99 paper, "New Quadric Metric for Simplifying Meshes with Appearance Attributes" is also a good take on the subject especially as it pertains to the error metric applied to attributes.
Seealso
Other Languages
See (CSharp)
Question
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Code¶
QuadricDecimation.cxx
#include <vtkPolyData.h> #include <vtkSphereSource.h> #include <vtkQuadricDecimation.h> #include <vtkXMLPolyDataReader.h> #include <vtkTriangleFilter.h> #include <vtkSmartPointer.h> #include <vtkPolyDataMapper.h> #include <vtkProperty.h> #include <vtkRenderWindow.h> #include <vtkRenderWindowInteractor.h> #include <vtkRenderer.h> #include <vtkCamera.h> #include <vtkNamedColors.h> int main(int argc, char *argv[]) { vtkSmartPointer<vtkPolyData> inputPolyData; if(argc > 1) { vtkSmartPointer<vtkXMLPolyDataReader> reader = vtkSmartPointer<vtkXMLPolyDataReader>::New(); reader->SetFileName(argv[1]); vtkSmartPointer<vtkTriangleFilter> triangles = vtkSmartPointer<vtkTriangleFilter>::New(); triangles->SetInputConnection(reader->GetOutputPort()); triangles->Update(); inputPolyData = triangles->GetOutput(); } else { vtkSmartPointer<vtkSphereSource> sphereSource = vtkSmartPointer<vtkSphereSource>::New(); sphereSource->SetThetaResolution(30); sphereSource->SetPhiResolution(15); sphereSource->Update(); inputPolyData = sphereSource->GetOutput(); } vtkSmartPointer<vtkNamedColors> colors = vtkSmartPointer<vtkNamedColors>::New(); std::cout << "Before decimation" << std::endl << "------------" << std::endl; std::cout << "There are " << inputPolyData->GetNumberOfPoints() << " points." << std::endl; std::cout << "There are " << inputPolyData->GetNumberOfPolys() << " polygons." << std::endl; vtkSmartPointer<vtkQuadricDecimation> decimate = vtkSmartPointer<vtkQuadricDecimation>::New(); decimate->SetInputData(inputPolyData); decimate->AttributeErrorMetricOn(); decimate->SetTargetReduction(.9); decimate->VolumePreservationOn(); decimate->Update(); vtkSmartPointer<vtkPolyData> decimated = vtkSmartPointer<vtkPolyData>::New(); decimated->ShallowCopy(decimate->GetOutput()); std::cout << "After decimation" << std::endl << "------------" << std::endl; std::cout << "There are " << decimated->GetNumberOfPoints() << " points." << std::endl; std::cout << "There are " << decimated->GetNumberOfPolys() << " polygons." << std::endl; std::cout << "Reduction: " << static_cast<double>((inputPolyData->GetNumberOfPolys() - decimated->GetNumberOfPolys())) / static_cast<double>(inputPolyData->GetNumberOfPolys()) << std::endl; vtkSmartPointer<vtkPolyDataMapper> inputMapper = vtkSmartPointer<vtkPolyDataMapper>::New(); inputMapper->SetInputData(inputPolyData); vtkSmartPointer<vtkProperty> backFace = vtkSmartPointer<vtkProperty>::New(); backFace->SetColor(colors->GetColor3d("gold").GetData()); vtkSmartPointer<vtkActor> inputActor = vtkSmartPointer<vtkActor>::New(); inputActor->SetMapper(inputMapper); inputActor->GetProperty()->SetInterpolationToFlat(); inputActor->GetProperty()->SetColor(colors->GetColor3d("flesh").GetData()); inputActor->SetBackfaceProperty(backFace); vtkSmartPointer<vtkPolyDataMapper> decimatedMapper = vtkSmartPointer<vtkPolyDataMapper>::New(); decimatedMapper->SetInputData(decimated); vtkSmartPointer<vtkActor> decimatedActor = vtkSmartPointer<vtkActor>::New(); decimatedActor->SetMapper(decimatedMapper); decimatedActor->GetProperty()->SetColor(colors->GetColor3d("flesh").GetData()); decimatedActor->GetProperty()->SetInterpolationToFlat(); decimatedActor->SetBackfaceProperty(backFace); // There will be one render window vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New(); renderWindow->SetSize(600, 300); // And one interactor vtkSmartPointer<vtkRenderWindowInteractor> interactor = vtkSmartPointer<vtkRenderWindowInteractor>::New(); interactor->SetRenderWindow(renderWindow); // Define viewport ranges // (xmin, ymin, xmax, ymax) double leftViewport[4] = {0.0, 0.0, 0.5, 1.0}; double rightViewport[4] = {0.5, 0.0, 1.0, 1.0}; // Setup both renderers vtkSmartPointer<vtkRenderer> leftRenderer = vtkSmartPointer<vtkRenderer>::New(); renderWindow->AddRenderer(leftRenderer); leftRenderer->SetViewport(leftViewport); leftRenderer->SetBackground(colors->GetColor3d("burlywood").GetData()); vtkSmartPointer<vtkRenderer> rightRenderer = vtkSmartPointer<vtkRenderer>::New(); renderWindow->AddRenderer(rightRenderer); rightRenderer->SetViewport(rightViewport); rightRenderer->SetBackground(colors->GetColor3d("slate_grey").GetData()); // Add the sphere to the left and the cube to the right leftRenderer->AddActor(inputActor); rightRenderer->AddActor(decimatedActor); // Shared camera looking down the -y axis vtkSmartPointer<vtkCamera> camera = vtkSmartPointer<vtkCamera>::New(); camera->SetPosition (0, -1, 0); camera->SetFocalPoint (0, 0, 0); camera->SetViewUp (0, 0, 1); camera->Elevation(30); camera->Azimuth(30); leftRenderer->SetActiveCamera(camera); rightRenderer->SetActiveCamera(camera); leftRenderer->ResetCamera(); leftRenderer->ResetCameraClippingRange(); renderWindow->Render(); interactor->Start(); return EXIT_SUCCESS; }
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.3 FATAL_ERROR) project(QuadricDecimation) find_package(VTK COMPONENTS vtkCommonColor vtkCommonCore vtkCommonDataModel vtkFiltersCore vtkFiltersSources vtkIOXML vtkInteractionStyle vtkRenderingCore vtkRenderingFreeType vtkRenderingOpenGL2 QUIET) if (NOT VTK_FOUND) message("Skipping QuadricDecimation: ${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(QuadricDecimation MACOSX_BUNDLE QuadricDecimation.cxx ) target_link_libraries(QuadricDecimation PRIVATE ${VTK_LIBRARIES}) else () # include all components add_executable(QuadricDecimation MACOSX_BUNDLE QuadricDecimation.cxx ) target_link_libraries(QuadricDecimation PRIVATE ${VTK_LIBRARIES}) # vtk_module_autoinit is needed vtk_module_autoinit( TARGETS QuadricDecimation MODULES ${VTK_LIBRARIES} ) endif ()
Download and Build QuadricDecimation¶
Click here to download QuadricDecimation and its CMakeLists.txt file. Once the tarball QuadricDecimation.tar has been downloaded and extracted,
cd QuadricDecimation/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:
./QuadricDecimation
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.