VTK/VTKMatlab

It is possible (and highly desirable) to provide VTK bindings for Matlab. For that to happen one has to write a C++ file to be compiled with mex compiler right from under Matlab. Example:

/************************************************************************** Copyright (C) 2005 Dominik Szczerba <domi at vision ee ethz ch> ***************************************************************************/ #include <cstdlib> #include <cmath> /* MEX HEADERS */ #include <mex.h> /* VTK HEADERS */ #include <vtkPolyData.h> #include <vtkPoints.h> #include <vtkCellArray.h> #include <vtkDoubleArray.h> #include <vtkPolyData.h> #include <vtkCell.h> #include <vtkCellData.h> #include <vtkDataSet.h> #include <vtkDataSetAttributes.h> #include <vtkProperty.h> #include <vtkDataSetMapper.h> #include <vtkPolyDataMapper.h> #include <vtkActor.h> #include <vtkRenderer.h> #include <vtkRenderWindow.h> #include <vtkRenderWindowInteractor.h> #include <vtkInteractorStyleTrackballCamera.h> /* MAIN FUNCTION */ void mexFunction(int nlhs,mxArray *plhs[],int nrhs,const mxArray *prhs[]){ double *v; // Vertices double *f; // Faces unsigned int nV, nF, nC=0, i, j; if(nrhs<2) mexErrMsgTxt("2+ input args required"); double* dcolors = 0; vtkDoubleArray* dcolarr = 0; nV = mxGetM(prhs[0]); nF = mxGetM(prhs[1]); v = mxGetPr(prhs[0]); f = (double*)mxGetPr(prhs[1]); if(nrhs>=3){ //mexPrintf("found color information\n"); nC = mxGetM(prhs[2]); if(nC!=nF) mexErrMsgTxt("dimension mismatch"); dcolors = mxGetPr(prhs[2]); dcolarr = vtkDoubleArray::New(); dcolarr->SetName("aCellScalar"); dcolarr->SetArray(dcolors,nF,0); } mexPrintf("got %d nodes, %d faces and %d colors\n",nV,nF,nC); // Initialize vtk variables vtkPolyData *surf = vtkPolyData::New(); vtkPoints *sverts = vtkPoints::New(); vtkCellArray *sfaces = vtkCellArray::New(); // Load the point, cell, and data attributes. // indexes in VTK are 0-based, in Matlab 1-based const int offset = -1; for(i=0; i<nV; i++) sverts->InsertPoint(i,v[i],v[nV+i],v[2*nV+i]); for(i=0; i<nF; i++){ sfaces->InsertNextCell(3); for(j=0;j<3;j++){ int idx = (unsigned int)f[j*nF+i]+offset; if(idx<0 || idx>=nV) //mexPrintf("Warning : wrong index\n"); mexErrMsgTxt("wrong index"); sfaces->InsertCellPoint(vtkIdType(idx)); } } // assign the pieces to the vtkPolyData. surf->SetPoints(sverts); surf->SetPolys(sfaces); sverts->Delete(); sfaces->Delete(); if(nC>0){ surf->GetCellData()->SetScalars(dcolarr); } // now render vtkDataSetMapper::SetResolveCoincidentTopologyToPolygonOffset(); vtkPolyDataMapper *skinMapper = vtkPolyDataMapper::New(); vtkActor *skin = vtkActor::New(); vtkRenderer *aRenderer = vtkRenderer::New(); vtkRenderWindow *renWin = vtkRenderWindow::New(); vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor::New(); skinMapper->SetInput(surf); //skinMapper->ScalarVisibilityOff(); if(nC>0){ skinMapper->ScalarVisibilityOn(); skinMapper->SetScalarRange(0,1); } skin->SetMapper(skinMapper); skin->GetProperty()->SetAmbient(0.1); skin->GetProperty()->SetDiffuse(0.3); skin->GetProperty()->SetSpecular(1.0); skin->GetProperty()->SetSpecularPower(30.0); aRenderer->AddActor(skin); aRenderer->SetBackground(0.2,0.2,0.2); //needed after camera moves //aRenderer->ResetCameraClippingRange (); iren->SetRenderWindow(renWin); renWin->AddRenderer(aRenderer); renWin->SetSize(500,500); renWin->Render(); vtkInteractorStyleTrackballCamera *style = vtkInteractorStyleTrackballCamera::New(); iren->SetInteractorStyle(style); // Start interactive rendering iren->Start(); // clean up surf->Delete(); skinMapper->Delete(); skin->Delete(); aRenderer->Delete(); renWin->Delete(); style->Delete(); iren->Delete(); }

[x y z v] = flow; q = z./x.*y.^3; mesh=isosurface(x, y, z, q, -.08, v); [N,M]=size(mesh.faces) scalars=[0:1:N-1]'/(N-1); vtkPolyDataRenderer(mesh.vertices,mesh.faces,scalars)