TopoOffsetTetMesh.h

#pragma once
 
#include <igl/Timer.h>
#include <wmtk/TetMesh.h>
#include <wmtk/simplex/Simplex.hpp>
#include "Parameters.h"
#include "SimplicialComplexBVH.hpp"
 
// clang-format off
#include <wmtk/utils/DisableWarnings.hpp>
#include <wmtk/utils/EnableWarnings.hpp>
// clang-format on
 
using CellTag = std::set<int64_t>;
 
 
namespace wmtk::components::topological_offset {
 
 
const int64_t TEMP_OFFSET_TET_TAG = -1;
const CellTag TEMP_OFFSET_TET_TAG_SET{TEMP_OFFSET_TET_TAG};
 
 
// for all attributes:
// label: 0=default, 1=input, 2=offset
class VertexAttributes
{
public:
    Vector3d m_posf;
    int label = 0;
    size_t component_id = 0;
 
    VertexAttributes() {};
    VertexAttributes(const Vector3d& p);
};
 
 
class EdgeAttributes
{
public:
    int label = 0;
};
 
 
class FaceAttributes
{
public:
    int label = 0;
};
 
 
class TetAttributes
{
public:
    int label = 0;
    CellTag tag;
};
 
 
class TopoOffsetTetMesh : public wmtk::TetMesh
{
public: // mode for splitting in marching tets
    enum class EdgeSplitMode {
        Midpoint = 0,
        BinarySearch = 1, // requires that every edge being split has one vertex labelled 0 and the
                          // other 1 or 2
        Initial = 2 // requires that every edge being split has one vertex labelled 0 and the other
                    // 1 or 2. This is really hacky. This initializes the offset using the minimum
                    // of half the target distance and half the edge length. Basically we want to
                    // initialize the offset with as high of quality as possible
    };
 
public:
    int m_vtu_counter = 0;
    std::array<size_t, 4> m_init_counts = {{0, 0, 0, 0}};
    size_t m_tags_count;
    SimplicialComplexBVH m_input_complex_bvh;
    EdgeSplitMode m_edge_split_mode = EdgeSplitMode::Midpoint;
 
    // tag map stuff
    std::map<std::string, int64_t> m_tag_name_to_id;
    std::map<int64_t, std::string> m_tag_id_to_name;
    // std::vector<CellTag> m_offset_tags_ids;
    CellTag m_offset_output_tag_ids;
 
    // if in 'singlebody' mode
    bool m_singlebody = false;
    int64_t m_single_tag;
 
    // dont actually use, just for retaining in output
    bool m_has_envelope;
    MatrixXd m_V_envelope;
    MatrixXi m_F_envelope;
 
    Parameters& m_params;
 
    using VertAttCol = wmtk::AttributeCollection<VertexAttributes>;
    using EdgeAttCol = wmtk::AttributeCollection<EdgeAttributes>;
    using FaceAttCol = wmtk::AttributeCollection<FaceAttributes>;
    using TetAttCol = wmtk::AttributeCollection<TetAttributes>;
    VertAttCol m_vertex_attribute;
    EdgeAttCol m_edge_attribute;
    FaceAttCol m_face_attribute;
    TetAttCol m_tet_attribute;
 
    TopoOffsetTetMesh(Parameters& _m_params, int _num_threads = 0)
        : m_params(_m_params)
    {
        NUM_THREADS = _num_threads;
        p_vertex_attrs = &m_vertex_attribute;
        p_edge_attrs = &m_edge_attribute;
        p_face_attrs = &m_face_attribute;
        p_tet_attrs = &m_tet_attribute;
    }
 
    ~TopoOffsetTetMesh() {}
 
    void init_from_image(
        const MatrixXd& V,
        const MatrixXi& T,
        const MatrixSi& T_tags,
        const MatrixXd& V_env,
        const MatrixXi F_env,
        const std::vector<std::string>& tag_names);
 
    void label_input_complex();
 
    bool empty_input_complex();
 
    void init_input_complex_bvh();
 
    void edge_split_binary_search(const size_t v1, const size_t v2, Vector3d& p_new) const;
 
    size_t flood_fill();
 
    bool split_edge_before(const Tuple& t) override;
    bool split_edge_after(const Tuple& t) override;
    bool split_face_before(const Tuple& t) override;
    bool split_face_after(const Tuple& t) override;
    bool split_tet_before(const Tuple& t) override;
    bool split_tet_after(const Tuple& t) override;
    bool invariants(const std::vector<Tuple>& tets) override;
 
    void marching_tets();
 
 
 
    bool is_simplicially_embedded() const;
 
    bool tet_is_simp_emb(const Tuple& t) const;
 
    void simplicial_embedding();
 
 
    bool tag_tet_consistent_topology(size_t t_id, int64_t tag) const;
 
    bool offset_tet_consistent_topology(const size_t t_id) const;
 
    bool tet_is_in_offset_conservative(const size_t t_id, const double threshold_r) const;
 
    void grow_offset_conservative();
 
    void set_offset_tet_tags();
 
    bool offset_is_manifold();
 
    void write_input_complex(const std::string& path); // write components labeled to be offset
    void write_vtu(const std::string& path);
    // void write_msh(const std::string& file);
    void write_msh_groups(const std::string& file);
 
private:
    struct EdgeSplitCache
    {
        size_t v1_id;
        size_t v2_id;
        VertexAttributes new_v;
 
        // cache edge attributes
        EdgeAttributes split_e;
        std::map<size_t, EdgeAttributes> internal_e;
        std::map<simplex::Edge, EdgeAttributes> external_e; // edge is boundary edge (not link)
        std::map<simplex::Edge, EdgeAttributes> link_e;
 
        // cache face attributes
        std::map<size_t, FaceAttributes> split_f;
        std::map<simplex::Edge, FaceAttributes> internal_f;
        std::map<std::pair<simplex::Edge, size_t>, FaceAttributes> external_f;
 
        // cache tet attributes
        std::map<simplex::Edge, TetAttributes> tets;
    };
    tbb::enumerable_thread_specific<EdgeSplitCache> edge_split_cache;
 
    struct FaceSplitCache
    {
        size_t v1_id;
        size_t v2_id;
        size_t v3_id;
 
        // cache edge attributes
        std::map<simplex::Edge, EdgeAttributes> existing_e;
 
        // cache face attributes
        std::map<simplex::Face, FaceAttributes> existing_f;
        int splitf_label;
 
        // cache tet attributes
        std::map<size_t, TetAttributes> tets;
    };
    tbb::enumerable_thread_specific<FaceSplitCache> face_split_cache;
 
    struct TetSplitCache
    {
        std::array<size_t, 4> v_ids;
 
        // cache retained edge attributes
        std::map<simplex::Edge, EdgeAttributes> existing_e;
 
        // cache retained face attributes
        std::map<simplex::Face, FaceAttributes> existing_f;
 
        // cache tet attribute
        TetAttributes tet;
    };
    tbb::enumerable_thread_specific<TetSplitCache> tet_split_cache;
 
private: // helpers
    bool any_tag_present(const CellTag& tag1, const CellTag& tag2)
    {
        if (tag2.empty()) {
            return tag1.empty();
        }
        if (tag1.empty()) { // tag1 is ambient, tag2 is not
            return false;
        }
 
        for (const int64_t& i : tag1) {
            if (tag2.find(i) != tag2.end()) {
                return true;
            }
        }
        return false;
    }
 
    void sort_edges_by_length(std::vector<simplex::Edge>& edges)
    {
        std::sort(
            edges.begin(),
            edges.end(),
            [this](const simplex::Edge& e1, const simplex::Edge& e2) {
                double len1 = (m_vertex_attribute[e1.vertices()[0]].m_posf -
                               m_vertex_attribute[e1.vertices()[1]].m_posf)
                                  .norm();
                double len2 = (m_vertex_attribute[e2.vertices()[0]].m_posf -
                               m_vertex_attribute[e2.vertices()[1]].m_posf)
                                  .norm();
                return len1 > len2;
            });
    }
 
public: // helpers
    std::vector<Tuple> get_face_adjacent_tets(const Tuple& t) const
    {
        std::vector<Tuple> adj_tets;
        auto tet_1 = t.switch_tetrahedron(*this);
        if (tet_1) {
            adj_tets.push_back(tet_1.value());
        }
        auto tet_2 = t.switch_face(*this).switch_tetrahedron(*this);
        if (tet_2) {
            adj_tets.push_back(tet_2.value());
        }
        auto tet_3 = t.switch_edge(*this).switch_face(*this).switch_tetrahedron(*this);
        if (tet_3) {
            adj_tets.push_back(tet_3.value());
        }
        auto tet_4 =
            t.switch_vertex(*this).switch_edge(*this).switch_face(*this).switch_tetrahedron(*this);
        if (tet_4) {
            adj_tets.push_back(tet_4.value());
        }
        return adj_tets;
    }
 
    std::vector<size_t> connected_components_helper(const size_t& v_id)
    {
        auto onering_v_ids = get_one_ring_vids_for_vertex(v_id);
        std::vector<size_t> ret_v_ids;
        for (const size_t& other_v_id : onering_v_ids) {
            size_t e_id = tuple_from_edge({{v_id, other_v_id}}).eid(*this);
            if (m_edge_attribute[e_id].label != 0) { // edge labelled 1 or 2
                ret_v_ids.push_back(other_v_id);
            }
        }
        return ret_v_ids;
    }
 
    void reset_connected_components()
    {
        auto verts = get_vertices();
        for (const Tuple& v : verts) {
            size_t v_id = v.vid(*this);
            m_vertex_attribute[v_id].component_id = 0;
        }
    }
};
 
 
} // namespace wmtk::components::topological_offset