VTK/Examples/Broken/GridPointCloud
From KitwarePublic
This example is currently broken. We can determine which cell a point is in, but how to determine which points are in a particular cell?
This example demonstrates how to overlay a grid structure (vtkImageData) over a set of points (in this case, vtkPolyData). This allows queries such as "Which cell (grid voxel) is a particular point in?" and "Which points are in a particular grid voxel?".
GridPointCloud.cxx
#include <vtkSmartPointer.h> #include <vtkPointSource.h> #include <vtkImageData.h> #include <vtkCellLocator.h> int main(int argc, char *argv[]) { vtkSmartPointer<vtkPointSource> pointSource = vtkSmartPointer<vtkPointSource>::New(); pointSource->SetNumberOfPoints(10); pointSource->Update(); double bounds[6]; pointSource->GetOutput()->GetBounds(bounds); vtkSmartPointer<vtkImageData> grid = vtkSmartPointer<vtkImageData>::New(); grid->SetOrigin(bounds[0], bounds[2], bounds[4]); double voxelSize = .1; double numVoxels = 10.0; //the number of voxels in each dimension grid->SetSpacing((bounds[1]-bounds[0])/numVoxels, (bounds[3]-bounds[2])/numVoxels, (bounds[5]-bounds[4])/numVoxels); int extent[6]; extent[0] = 0; extent[1] = numVoxels; extent[2] = 0; extent[3] = numVoxels; extent[4] = 0; extent[5] = numVoxels; grid->SetExtent(extent); grid->Update(); vtkSmartPointer<vtkCellLocator> cellLocator = vtkSmartPointer<vtkCellLocator>::New(); cellLocator->SetDataSet(grid); cellLocator->BuildLocator(); for(unsigned int i = 0; i < pointSource->GetOutput()->GetNumberOfPoints(); i++) { double p[3]; pointSource->GetOutput()->GetPoint(i,p); int cellId = cellLocator->FindCell(p); cout << "Point " << i << " is in cell " << cellId << endl; } return EXIT_SUCCESS; }
CMakeLists.txt
cmake_minimum_required(VERSION 2.6) PROJECT(GridPointCloud) FIND_PACKAGE(VTK REQUIRED) INCLUDE(${VTK_USE_FILE}) ADD_EXECUTABLE(GridPointCloud GridPointCloud.cxx) TARGET_LINK_LIBRARIES(GridPointCloud vtkHybrid)
