Francis Williams
4f030acb67
* Add a utility function which computes a sparse set of epsilon-sized grid cells surrounding an input surface. The function takes a point on the surface as input and finds all those epsilon grid cells that intersect the surface using a breadth first search over the grid space. * Add a utility function which computes a sparse set of epsilon-sized grid cells surrounding an input surface. The function takes a point on the surface as input and finds all those epsilon grid cells that intersect the surface using a breadth first search over the grid space.
51 lines
1.7 KiB
C++
Executable File
51 lines
1.7 KiB
C++
Executable File
#include <igl/copyleft/marching_cubes.h>
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#include <igl/sparse_voxel_grid.h>
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#include <igl/opengl/glfw/Viewer.h>
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#include <Eigen/Core>
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#include <iostream>
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#include "tutorial_shared_path.h"
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int main(int argc, char * argv[])
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{
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// An implicit function which is zero on the surface of a sphere centered at the origin with radius 1
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// This function is negative inside the surface and positive outside the surface
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std::function<double(const Eigen::RowVector3d&)> scalar_func = [](const Eigen::RowVector3d& pt) -> double {
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return pt.norm() - 1.0;
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};
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// We know that the point (0, 0, 1) lies on the implicit surface
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Eigen::RowVector3d p0(0., 0., 1.);
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// Construct a sparse voxel grid whose cubes have edge length eps = 0.1.
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// The cubes will form a thin shell around the implicit surface
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const double eps = 0.1;
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// CS will hold one scalar value at each cube vertex corresponding
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// the value of the implicit at that vertex
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Eigen::VectorXd CS;
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// CV will hold the positions of the corners of the sparse voxel grid
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Eigen::MatrixXd CV;
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// CI is a #cubes x 8 matrix of indices where each row contains the
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// indices into CV of the 8 corners of a cube
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Eigen::MatrixXi CI;
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// Construct the voxel grid, populating CS, CV, and CI
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igl::sparse_voxel_grid(p0, scalar_func, eps, CS, CV, CI);
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// Given the sparse voxel grid, use Marching Cubes to construct a triangle mesh of the surface
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Eigen::MatrixXi F;
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Eigen::MatrixXd V;
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igl::copyleft::marching_cubes(CS, CV, CI, V, F);
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// Draw the meshed implicit surface
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igl::opengl::glfw::Viewer viewer;
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viewer.data().clear();
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viewer.data().set_mesh(V,F);
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viewer.data().set_face_based(true);
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viewer.launch();
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}
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