1 #include <igl/avg_edge_length.h>
2 #include <igl/cotmatrix.h>
3 #include <igl/invert_diag.h>
4 #include <igl/massmatrix.h>
5 #include <igl/parula.h>
6 #include <igl/per_corner_normals.h>
7 #include <igl/per_face_normals.h>
8 #include <igl/per_vertex_normals.h>
9 #include <igl/principal_curvature.h>
10 #include <igl/read_triangle_mesh.h>
11 #include <igl/opengl/glfw/Viewer.h>
12 #include "tutorial_shared_path.h"
13
14 Eigen::MatrixXd V;
15 Eigen::MatrixXi F;
16
main(int argc,char * argv[])17 int main(int argc, char *argv[])
18 {
19 using namespace Eigen;
20 std::string filename = TUTORIAL_SHARED_PATH "/fertility.off";
21 if(argc>1)
22 {
23 filename = argv[1];
24 }
25 // Load a mesh in OFF format
26 igl::read_triangle_mesh(filename, V, F);
27
28 // Alternative discrete mean curvature
29 MatrixXd HN;
30 SparseMatrix<double> L,M,Minv;
31 igl::cotmatrix(V,F,L);
32 igl::massmatrix(V,F,igl::MASSMATRIX_TYPE_VORONOI,M);
33 igl::invert_diag(M,Minv);
34 // Laplace-Beltrami of position
35 HN = -Minv*(L*V);
36 // Extract magnitude as mean curvature
37 VectorXd H = HN.rowwise().norm();
38
39 // Compute curvature directions via quadric fitting
40 MatrixXd PD1,PD2;
41 VectorXd PV1,PV2;
42 igl::principal_curvature(V,F,PD1,PD2,PV1,PV2);
43 // mean curvature
44 H = 0.5*(PV1+PV2);
45
46 igl::opengl::glfw::Viewer viewer;
47 viewer.data().set_mesh(V, F);
48
49
50 // Compute pseudocolor
51 MatrixXd C;
52 igl::parula(H,true,C);
53 viewer.data().set_colors(C);
54
55 // Average edge length for sizing
56 const double avg = igl::avg_edge_length(V,F);
57
58 // Draw a blue segment parallel to the minimal curvature direction
59 const RowVector3d red(0.8,0.2,0.2),blue(0.2,0.2,0.8);
60 viewer.data().add_edges(V + PD1*avg, V - PD1*avg, blue);
61
62 // Draw a red segment parallel to the maximal curvature direction
63 viewer.data().add_edges(V + PD2*avg, V - PD2*avg, red);
64
65 // Hide wireframe
66 viewer.data().show_lines = false;
67
68 viewer.launch();
69 }
70