main.cpp

#include "tutte.h"
#include "lscm.h"
#include <igl/read_triangle_mesh.h>
#include <igl/per_vertex_normals.h>
#include <igl/opengl/glfw/Viewer.h>
#include <Eigen/Core>
#include <string>
#include <iostream>

int main(int argc, char *argv[])
{
  // Load input meshes
  Eigen::MatrixXd V,U_lscm,U_tutte,U;
  Eigen::MatrixXi F;
  igl::read_triangle_mesh(
    (argc>1?argv[1]:"../data/beetle.obj"),V,F);
  igl::opengl::glfw::Viewer viewer;
  std::cout<<R"(
[space]  Toggle whether displaying 3D surface or 2D parameterization
C,c      Toggle checkerboard
t        Switch parameterization to Tutte embedding
l        Switch parameterization to Least squares conformal mapping
)";
  tutte(V,F,U_tutte);
  lscm(V,F,U_lscm);
  // Fit parameterization in unit sphere
  const auto normalize = [](Eigen::MatrixXd &U)
  {
    U.rowwise() -= U.colwise().mean().eval();
    U.array() /= 
      (U.colwise().maxCoeff() - U.colwise().minCoeff()).maxCoeff()/2.0;
  };
  normalize(V);
  normalize(U_tutte);
  normalize(U_lscm);

  bool plot_parameterization = false;
  const auto & update = [&]()
  {
    if(plot_parameterization)
    {
      // Viewer wants 3D coordinates, so pad UVs with column of zeros
      viewer.data().set_vertices(
        (Eigen::MatrixXd(V.rows(),3)<<
         U.col(0),Eigen::VectorXd::Zero(V.rows()),U.col(1)).finished());
    }else
    {
      viewer.data().set_vertices(V);
    }
    viewer.data().compute_normals();
    viewer.data().set_uv(U*10);
  };
  viewer.callback_key_pressed = 
    [&](igl::opengl::glfw::Viewer &, unsigned int key, int)
  {
    switch(key)
    {
      case ' ':
        plot_parameterization ^= 1;
        break;
      case 'l':
        U = U_lscm;
        break;
      case 't':
        U = U_tutte;
        break;
      case 'C':
      case 'c':
        viewer.data().show_texture ^= 1;
        break;
      default:
        return false;
    }
    update();
    return true;
  };

  U = U_tutte;
  viewer.data().set_mesh(V,F);
  Eigen::MatrixXd N;
  igl::per_vertex_normals(V,F,N);
  viewer.data().set_colors(N.array()*0.5+0.5);
  update();
  viewer.data().show_texture = true;
  viewer.data().show_lines = false;
  viewer.launch();

  return EXIT_SUCCESS;
}