cookbook.rst

Polymesh Cookbook

Loading a Mesh from a File

pm::Mesh m;
auto pos = m.vertices().make_attribute<tg::pos3>();

load("/path/to/file.ext", m, pos);

Laplacian Smoothing with Feature Edges

TODO

Extracting Edges as Segments

// given:
// pm::Mesh m;
// pm::vertex_attribute<tg::pos3> pos;

// functional style
auto edges0 = m.edges().map([&](pm::edge_handle e) {
        return tg::segment3(pos[e.vertexA()], pos[e.vertexB()]);
    }).to_vector();

// or

// classical style
std::vector<tg::segment3> edges;
edges.reserve(m.edges().size());
for (auto const& e : m.edges().to_vector())
    edges.emplace_back(tg::segment3(pos[e.vertexA()], pos[e.vertexB()]));

Add Triangle Faces to Mesh

pm::Mesh m;
auto pos = pm::vertex_attribute<tg::pos3>(m);

const auto n = 10;
std::vector<tg::triangle3> tris;
tris.reserve(n);

// some box to sample random positions
const auto box = tg::box3(tg::aabb3({-n, -n, -n}, {n, n, n}));

tg::rng rng;
// create random triangles
for (auto i = 0u; i < n; ++i)
    tris.emplace_back(tg::triangle3(tg::uniform(rng, box), tg::uniform(rng, box), tg::uniform(rng, box)));

for (auto const& tri : tris)
{
    /// add vertices to topology
    const auto vh0 = m.vertices().add();
    const auto vh1 = m.vertices().add();
    const auto vh2 = m.vertices().add();

    /// add vertex positions
    pos[vh0] = tri.pos0;
    pos[vh1] = tri.pos1;
    pos[vh2] = tri.pos2;

    /// add face to topology
    m.faces().add(vh0, vh1, vh2);
}

// note that this will generate a triangle soup only. to obtain a sound mesh, deduplicate it
// triangles that share a certain position will then be properly connected
pm::deduplicate(m, pos);
m.compactify();