281 lines
10 KiB
C++
281 lines
10 KiB
C++
#ifndef MESHSPLITIMPL_HPP
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#define MESHSPLITIMPL_HPP
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// Disable meaningless boost warning on MSVC
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#ifdef _MSC_VER
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#pragma warning( push )
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#pragma warning( disable : 4805 )
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#endif
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#include "TriangleMesh.hpp"
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#include "libnest2d/tools/benchmark.h"
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#include "Execution/ExecutionTBB.hpp"
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namespace Slic3r {
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template<class ExPolicy>
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std::vector<Vec3i32> create_face_neighbors_index(ExPolicy &&ex, const indexed_triangle_set &its);
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namespace meshsplit_detail {
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template<class Its, class Enable = void> struct ItsWithNeighborsIndex_ {
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using Index = typename Its::Index;
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static const indexed_triangle_set &get_its(const Its &m) { return m.get_its();}
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static const Index &get_index(const Its &m) { return m.get_index(); }
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};
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// Define a default neighbors index for indexed_triangle_set
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template<> struct ItsWithNeighborsIndex_<indexed_triangle_set> {
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using Index = std::vector<Vec3i32>;
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static const indexed_triangle_set &get_its(const indexed_triangle_set &its) noexcept { return its; }
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static Index get_index(const indexed_triangle_set &its) noexcept
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{
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return create_face_neighbors_index(ex_tbb, its);
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}
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};
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// Discover connected patches of facets one by one.
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template<class NeighborIndex>
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struct NeighborVisitor {
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NeighborVisitor(const indexed_triangle_set &its, const NeighborIndex &neighbor_index) :
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its(its), neighbor_index(neighbor_index) {
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m_visited.assign(its.indices.size(), false);
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m_facestack.reserve(its.indices.size());
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}
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NeighborVisitor(const indexed_triangle_set &its, NeighborIndex &&aneighbor_index) :
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its(its), neighbor_index(m_neighbor_index_data), m_neighbor_index_data(std::move(aneighbor_index)) {
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m_visited.assign(its.indices.size(), false);
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m_facestack.reserve(its.indices.size());
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}
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template<typename Visitor>
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void visit(Visitor visitor)
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{
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// find the next unvisited facet and push the index
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auto facet = std::find(m_visited.begin() + m_seed, m_visited.end(), false);
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m_seed = facet - m_visited.begin();
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if (facet != m_visited.end()) {
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// Skip this element in the next round.
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auto idx = m_seed ++;
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if (! visitor(idx))
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return;
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this->push(idx);
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m_visited[idx] = true;
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while (! m_facestack.empty()) {
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size_t facet_idx = this->pop();
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for (auto neighbor_idx : neighbor_index[facet_idx]) {
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assert(neighbor_idx < int(m_visited.size()));
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if (neighbor_idx >= 0 && !m_visited[neighbor_idx]) {
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if (! visitor(size_t(neighbor_idx)))
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return;
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m_visited[neighbor_idx] = true;
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this->push(stack_el(neighbor_idx));
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}
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}
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}
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}
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}
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const indexed_triangle_set &its;
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const NeighborIndex &neighbor_index;
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private:
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// If initialized with &&neighbor_index, take the ownership of the data.
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const NeighborIndex m_neighbor_index_data;
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std::vector<char> m_visited;
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using stack_el = size_t;
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std::vector<stack_el> m_facestack;
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void push(const stack_el &s) { m_facestack.emplace_back(s); }
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stack_el pop() { stack_el ret = m_facestack.back(); m_facestack.pop_back(); return ret; }
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// Last face visited.
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size_t m_seed { 0 };
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};
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} // namespace meshsplit_detail
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// Funky wrapper for timinig of its_split() using various neighbor index creating methods, see sandboxes/its_neighbor_index/main.cpp
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template<class IndexT> struct ItsNeighborsWrapper
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{
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using Index = IndexT;
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const indexed_triangle_set &its;
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const IndexT &index_ref;
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const IndexT index;
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// Keeping a reference to index, the caller is responsible for keeping the index alive.
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ItsNeighborsWrapper(const indexed_triangle_set &its, const IndexT &index) : its{its}, index_ref{index} {}
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// Taking ownership of the index.
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ItsNeighborsWrapper(const indexed_triangle_set &its, IndexT &&aindex) : its{its}, index_ref{index}, index(std::move(aindex)) {}
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const auto& get_its() const noexcept { return its; }
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const auto& get_index() const noexcept { return index_ref; }
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};
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// Can be used as the second argument to its_split to apply a functor on each
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// part, instead of collecting them into a container.
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template<class Fn>
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struct SplitOutputFn {
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Fn fn;
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SplitOutputFn(Fn f): fn{std::move(f)} {}
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SplitOutputFn &operator *() { return *this; }
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void operator=(indexed_triangle_set &&its) { fn(std::move(its)); }
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void operator=(indexed_triangle_set &its) { fn(its); }
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SplitOutputFn& operator++() { return *this; };
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};
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// Splits a mesh into multiple meshes when possible.
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template<class Its, class OutputIt>
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void its_split(const Its &m, OutputIt out_it)
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{
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using namespace meshsplit_detail;
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const indexed_triangle_set &its = ItsWithNeighborsIndex_<Its>::get_its(m);
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struct VertexConv {
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size_t part_id = std::numeric_limits<size_t>::max();
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size_t vertex_image;
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};
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std::vector<VertexConv> vidx_conv(its.vertices.size());
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meshsplit_detail::NeighborVisitor visitor(its, meshsplit_detail::ItsWithNeighborsIndex_<Its>::get_index(m));
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std::vector<size_t> facets;
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for (size_t part_id = 0;; ++part_id) {
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// Collect all faces of the next patch.
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facets.clear();
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visitor.visit([&facets](size_t idx) { facets.emplace_back(idx); return true; });
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if (facets.empty())
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break;
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// Create a new mesh for the part that was just split off.
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indexed_triangle_set mesh;
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mesh.indices.reserve(facets.size());
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mesh.vertices.reserve(std::min(facets.size() * 3, its.vertices.size()));
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// Assign the facets to the new mesh.
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for (size_t face_id : facets) {
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const auto &face = its.indices[face_id];
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Vec3i32 new_face;
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for (size_t v = 0; v < 3; ++v) {
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auto vi = face(v);
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if (vidx_conv[vi].part_id != part_id) {
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vidx_conv[vi] = {part_id, mesh.vertices.size()};
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mesh.vertices.emplace_back(its.vertices[size_t(vi)]);
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}
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new_face(v) = vidx_conv[vi].vertex_image;
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}
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mesh.indices.emplace_back(new_face);
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}
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*out_it = std::move(mesh);
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++out_it;
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}
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}
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template<class Its>
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std::vector<indexed_triangle_set> its_split(const Its &its)
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{
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auto ret = reserve_vector<indexed_triangle_set>(3);
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its_split(its, std::back_inserter(ret));
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return ret;
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}
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template<class Its>
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bool its_is_splittable(const Its &m)
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{
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meshsplit_detail::NeighborVisitor visitor(meshsplit_detail::ItsWithNeighborsIndex_<Its>::get_its(m), meshsplit_detail::ItsWithNeighborsIndex_<Its>::get_index(m));
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bool has_some = false;
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bool has_some2 = false;
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// Traverse the 1st patch fully.
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visitor.visit([&has_some](size_t idx) { has_some = true; return true; });
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if (has_some)
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// Just check whether there is any face of the 2nd patch.
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visitor.visit([&has_some2](size_t idx) { has_some2 = true; return false; });
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return has_some && has_some2;
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}
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template<class Its>
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size_t its_number_of_patches(const Its &m)
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{
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meshsplit_detail::NeighborVisitor visitor(meshsplit_detail::ItsWithNeighborsIndex_<Its>::get_its(m), meshsplit_detail::ItsWithNeighborsIndex_<Its>::get_index(m));
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size_t num_patches = 0;
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for (;;) {
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bool has_some = false;
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// Traverse the 1st patch fully.
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visitor.visit([&has_some](size_t idx) { has_some = true; return true; });
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if (! has_some)
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break;
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++ num_patches;
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}
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return num_patches;
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}
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template<class ExPolicy>
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std::vector<Vec3i32> create_face_neighbors_index(ExPolicy &&ex, const indexed_triangle_set &its)
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{
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const std::vector<stl_triangle_vertex_indices> &indices = its.indices;
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if (indices.empty()) return {};
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assert(! its.vertices.empty());
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auto vertex_triangles = VertexFaceIndex{its};
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static constexpr int no_value = -1;
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std::vector<Vec3i32> neighbors(indices.size(),
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Vec3i32(no_value, no_value, no_value));
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//for (int face_idx = 0; face_idx < indices.size(); face_idx++) {
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execution::for_each(ex, size_t(0), indices.size(),
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[&neighbors, &indices, &vertex_triangles] (size_t face_idx)
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{
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Vec3i32& neighbor = neighbors[face_idx];
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const stl_triangle_vertex_indices & triangle_indices = indices[face_idx];
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for (int edge_index = 0; edge_index < 3; ++edge_index) {
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// check if done
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int& neighbor_edge = neighbor[edge_index];
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if (neighbor_edge != no_value)
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// This edge already has a neighbor assigned.
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continue;
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Vec2i32 edge_indices = its_triangle_edge(triangle_indices, edge_index);
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// IMPROVE: use same vector for 2 sides of triangle
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for (const size_t other_face : vertex_triangles[edge_indices[0]]) {
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if (other_face <= face_idx) continue;
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const stl_triangle_vertex_indices &face_indices = indices[other_face];
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int vertex_index = its_triangle_vertex_index(face_indices, edge_indices[1]);
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// NOT Contain second vertex?
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if (vertex_index < 0) continue;
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// Has NOT oposite direction?
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if (edge_indices[0] != face_indices[(vertex_index + 1) % 3]) continue;
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//BBS: if this neighbor has already marked before, skip it
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if (neighbors[other_face][vertex_index] != no_value)
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continue;
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//BBS: the same triangle with opposite direction, also treat it as open edges
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//if (its_triangle_vertex_the_same(face_indices, triangle_indices))
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// continue;
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neighbor_edge = other_face;
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neighbors[other_face][vertex_index] = face_idx;
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break;
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}
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}
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}, execution::max_concurrency(ex));
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return neighbors;
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}
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} // namespace Slic3r
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#ifdef _MSC_VER
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#pragma warning( pop )
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#endif
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#endif // MESHSPLITIMPL_HPP
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