IsotropicRemeshing.h

#pragma once
 
#include <wmtk/utils/PartitionMesh.h>
#include <wmtk/utils/VectorUtils.h>
#include <wmtk/envelope/Envelope.hpp>
#include "wmtk/AttributeCollection.hpp"
 
// clang-format off
#include <wmtk/utils/DisableWarnings.hpp>
#include <igl/write_triangle_mesh.h>
#include <wmtk/threading/enumerable_thread_specific.hpp>
#include <fastenvelope/FastEnvelope.h>
#include <wmtk/utils/EnableWarnings.hpp>
// clang-format on
 
#include <Eigen/Core>
#include <Eigen/Geometry>
#include <atomic>
#include <memory>
#include <queue>
 
namespace wmtk::components::isotropic_remeshing {
 
struct VertexAttributes
{
    Eigen::Vector3d pos;
    // TODO: in fact, partition id should not be vertex attribute, it is a fixed marker to distinguish tuple/operations.
    size_t partition_id;
    bool freeze = false;
};
 
class IsotropicRemeshing : public wmtk::TriMesh
{
public:
    wmtk::SampleEnvelope m_envelope;
    bool m_has_envelope = false;
 
    using VertAttCol = wmtk::AttributeCollection<VertexAttributes>;
    VertAttCol vertex_attrs;
 
    int retry_limit = 10;
    IsotropicRemeshing(
        std::vector<Eigen::Vector3d> _m_vertex_positions,
        int num_threads = 1,
        bool use_exact = true);
 
    ~IsotropicRemeshing() {}
 
    void create_mesh(
        size_t n_vertices,
        const std::vector<std::array<size_t, 3>>& tris,
        const std::vector<size_t>& frozen_verts = std::vector<size_t>(),
        bool m_freeze = true,
        double eps = 0);
 
    struct PositionInfoCache
    {
        Eigen::Vector3d v1p;
        Eigen::Vector3d v2p;
        size_t partition_id;
    };
    wmtk::threading::enumerable_thread_specific<PositionInfoCache> position_cache;
 
    void cache_edge_positions(const Tuple& t);
 
    bool invariants(const std::vector<Tuple>& new_tris) override;
 
    // TODO: this should not be here
    void partition_mesh();
 
    // TODO: morton should not be here, but inside wmtk
    void partition_mesh_morton();
 
    size_t get_partition_id(const Tuple& loc) const
    {
        return vertex_attrs[loc.vid(*this)].partition_id;
    }
 
    bool smooth_all_vertices();
 
    Eigen::Vector3d smooth(const Tuple& t);
 
 
    Eigen::Vector3d tangential_smooth(const Tuple& t);
 
    bool collapse_edge_before(const Tuple& t) override;
    bool collapse_edge_after(const Tuple& t) override;
 
    bool swap_edge_before(const Tuple& t) override;
    bool swap_edge_after(const Tuple& t) override;
 
    std::vector<TriMesh::Tuple> new_edges_after(const std::vector<TriMesh::Tuple>& tris) const;
    std::vector<TriMesh::Tuple> new_edges_after_swap(const TriMesh::Tuple& t) const;
    std::vector<TriMesh::Tuple> replace_edges_after_split(
        const std::vector<TriMesh::Tuple>& tris,
        const size_t vid_threshold) const;
    std::vector<TriMesh::Tuple> new_sub_edges_after_split(
        const std::vector<TriMesh::Tuple>& tris) const;
 
 
    bool split_edge_before(const Tuple& t) override;
    bool split_edge_after(const Tuple& t) override;
 
    bool smooth_before(const Tuple& t) override;
    bool smooth_after(const Tuple& t) override;
 
    double compute_edge_cost_collapse(const TriMesh::Tuple& t, double L) const;
    double compute_edge_cost_split(const TriMesh::Tuple& t, double L) const;
    double compute_vertex_valence(const TriMesh::Tuple& t) const;
    std::vector<double> average_len_valen();
    bool split_remeshing(double L);
    bool collapse_remeshing(double L);
    bool swap_remeshing();
    bool uniform_remeshing(double L, int interations);
    bool write_triangle_mesh(std::string path);
};
 
} // namespace wmtk::components::isotropic_remeshing