BasicFlattening.cpp

Basic flattening demo

Demonstrates flattening of a triangular pyramid mesh using ABF++ and LSCM.

Note

The HalfEdgeMesh class currently assumes that the surface has a boundary, is manifold, and that the winding order of all faces is the same. Care should be taken that this assumption is not violated when constructing your mesh.

 
#include <iostream>
 
#include "OpenABF/OpenABF.hpp"
 
int main()
{
    // Define the flattening types
    using ABF = OpenABF::ABFPlusPlus<float>;
    using LSCM = OpenABF::AngleBasedLSCM<float, ABF::Mesh>;
    using Vec3f = OpenABF::Vec3f;
 
    // Pre-define vertices list
    const std::vector vertices = {Vec3f{0.f, 0.f, 0.f}, Vec3f{2.f, 0.f, 0.f},
                                  Vec3f{1.f, std::sqrt(3.f), 0.f},
                                  Vec3f{1.f, std::sqrt(3.f) / 3.f, std::sqrt(6.f) * 2.f / 3.f}};
 
    // Create the 4 pyramid vertices
    auto mesh = ABF::Mesh::New();
    mesh->insert_vertices(vertices);
 
    // Create the 3 pyramid triangles (the 4th is open)
    mesh->insert_faces({{1, 3, 0}, {3, 2, 0}, {3, 1, 2}});
 
    // Run ABF++
    std::size_t iters{0};
    float grad{OpenABF::INF<float>};
    ABF::Compute(mesh, iters, grad);
    std::cout << "ABF++ Final gradient: " << grad << std::endl;
    std::cout << "ABF++ Iterations: " << iters << std::endl;
 
    // Run LSCM
    LSCM::Compute(mesh);
 
    // Print flattened positions
    for (const auto& v : mesh->vertices()) {
        std::cout << v->idx << ": " << vertices[v->idx] << " -> " << v->pos << std::endl;
    }
 
    // Write the flattened mesh
    WriteMesh("openabf_example_basic_flattening.obj", mesh);
}