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5b89cb9 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 | #include <igl/avg_edge_length.h>
#include <igl/barycenter.h>
#include <igl/grad.h>
#include <igl/jet.h>
#include <igl/readDMAT.h>
#include <igl/readOFF.h>
#include <igl/opengl/glfw/Viewer.h>
#include <iostream>
int main(int argc, char *argv[])
{
using namespace Eigen;
using namespace std;
MatrixXd V;
MatrixXi F;
// Load a mesh in OFF format
igl::readOFF(TUTORIAL_SHARED_PATH "/cheburashka.off", V, F);
// Read scalar function values from a file, U: #V by 1
VectorXd U;
igl::readDMAT(TUTORIAL_SHARED_PATH "/cheburashka-scalar.dmat",U);
// Compute gradient operator: #F*3 by #V
SparseMatrix<double> G;
igl::grad(V,F,G);
// Compute gradient of U
MatrixXd GU = Map<const MatrixXd>((G*U).eval().data(),F.rows(),3);
// Compute gradient magnitude
const VectorXd GU_mag = GU.rowwise().norm();
igl::opengl::glfw::Viewer viewer;
viewer.data().set_mesh(V, F);
viewer.data().set_data(U);
// Average edge length divided by average gradient (for scaling)
const double max_size = igl::avg_edge_length(V,F) / GU_mag.mean();
// Draw a black segment in direction of gradient at face barycenters
MatrixXd BC;
igl::barycenter(V,F,BC);
const RowVector3d black(0,0,0);
viewer.data().add_edges(BC,BC+max_size*GU, black);
// Hide wireframe
viewer.data().show_lines = false;
viewer.launch();
}
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