Add working version of triangle trimming for hollowed meshes
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tamasmeszaros
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b8c1c13666
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@ -29,11 +29,21 @@ inline void _scale(S s, Contour3D &m) { for (auto &p : m.points) p *= s; }
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struct Interior {
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struct Interior {
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TriangleMesh mesh;
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TriangleMesh mesh;
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openvdb::FloatGrid::Ptr gridptr;
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openvdb::FloatGrid::Ptr gridptr;
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mutable std::optional<openvdb::FloatGrid::ConstAccessor> accessor;
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double closing_distance = 0.;
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double closing_distance = 0.;
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double thickness = 0.;
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double thickness = 0.;
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double voxel_scale = 1.;
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double voxel_scale = 1.;
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double nb_in = 3.;
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double nb_in = 3.; // narrow band width inwards
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double nb_out = 3.;
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double nb_out = 3.; // narrow band width outwards
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// Full narrow band is the sum of the two above values.
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void reset_accessor() const // This resets the accessor and its cache
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// Not a thread safe call!
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{
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if (gridptr)
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accessor = gridptr->getConstAccessor();
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}
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};
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};
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void InteriorDeleter::operator()(Interior *p)
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void InteriorDeleter::operator()(Interior *p)
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@ -313,16 +323,243 @@ void hollow_mesh(TriangleMesh &mesh, const Interior &interior, int flags)
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{
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{
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if (mesh.empty() || interior.mesh.empty()) return;
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if (mesh.empty() || interior.mesh.empty()) return;
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// if (flags & hfRemoveInsideTriangles && interior.gridptr)
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if (flags & hfRemoveInsideTriangles && interior.gridptr)
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// erase_inside_triangles_2(mesh, interior);
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remove_inside_triangles(mesh, interior);
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mesh.merge(interior.mesh);
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mesh.merge(interior.mesh);
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mesh.require_shared_vertices();
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mesh.require_shared_vertices();
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}
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}
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// Get the distance of p to the interior's zero iso_surface. Interior should
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// have its zero isosurface positioned at offset + closing_distance inwards form
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// the model surface.
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static double get_distance_raw(const Vec3f &p, const Interior &interior)
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{
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assert(interior.gridptr);
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if (!interior.accessor) interior.reset_accessor();
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auto v = (p * interior.voxel_scale).cast<double>();
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auto grididx = interior.gridptr->transform().worldToIndexCellCentered(
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{v.x(), v.y(), v.z()});
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return interior.accessor->getValue(grididx) ;
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}
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struct TriangleBubble { Vec3f center; double R; };
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// Return the distance of bubble center to the interior boundary or NaN if the
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// triangle is too big to be measured.
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static double get_distance(const TriangleBubble &b, const Interior &interior)
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{
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double R = b.R * interior.voxel_scale;
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double D = get_distance_raw(b.center, interior);
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return (D > 0. && R >= interior.nb_out) ||
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(D < 0. && R >= interior.nb_in) ||
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((D - R) < 0. && 2 * R > interior.thickness) ?
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std::nan("") :
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// FIXME: Adding interior.voxel_scale is a compromise supposed
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// to prevent the deletion of the triangles forming the interior
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// itself. This has a side effect that a small portion of the
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// bad triangles will still be visible.
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D - interior.closing_distance /*+ 2 * interior.voxel_scale*/;
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}
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double get_distance(const Vec3f &p, const Interior &interior)
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{
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double d = get_distance_raw(p, interior) - interior.closing_distance;
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return d / interior.voxel_scale;
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}
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// A face that can be divided. Stores the indices into the original mesh if its
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// part of that mesh and the vertices it consists of.
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enum { NEW_FACE = -1};
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struct DivFace {
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Vec3i indx;
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std::array<Vec3f, 3> verts;
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long faceid = NEW_FACE;
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long parent = NEW_FACE;
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};
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// Divide a face recursively and call visitor on all the sub-faces.
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template<class Fn>
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void divide_triangle(const DivFace &face, Fn &&visitor)
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{
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std::array<Vec3f, 3> edges = {(face.verts[0] - face.verts[1]),
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(face.verts[1] - face.verts[2]),
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(face.verts[2] - face.verts[0])};
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std::array<size_t, 3> edgeidx = {0, 1, 2};
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std::sort(edgeidx.begin(), edgeidx.end(), [&edges](size_t e1, size_t e2) {
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return edges[e1].squaredNorm() > edges[e2].squaredNorm();
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});
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DivFace child1, child2;
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child1.parent = face.faceid == NEW_FACE ? face.parent : face.faceid;
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child1.indx(0) = -1;
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child1.indx(1) = face.indx(edgeidx[1]);
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child1.indx(2) = face.indx((edgeidx[1] + 1) % 3);
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child1.verts[0] = (face.verts[edgeidx[0]] + face.verts[(edgeidx[0] + 1) % 3]) / 2.;
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child1.verts[1] = face.verts[edgeidx[1]];
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child1.verts[2] = face.verts[(edgeidx[1] + 1) % 3];
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if (visitor(child1))
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divide_triangle(child1, std::forward<Fn>(visitor));
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child2.parent = face.faceid == NEW_FACE ? face.parent : face.faceid;
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child2.indx(0) = -1;
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child2.indx(1) = face.indx(edgeidx[2]);
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child2.indx(2) = face.indx((edgeidx[2] + 1) % 3);
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child2.verts[0] = child1.verts[0];
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child2.verts[1] = face.verts[edgeidx[2]];
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child2.verts[2] = face.verts[(edgeidx[2] + 1) % 3];
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if (visitor(child2))
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divide_triangle(child2, std::forward<Fn>(visitor));
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}
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void remove_inside_triangles(TriangleMesh &mesh, const Interior &interior)
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void remove_inside_triangles(TriangleMesh &mesh, const Interior &interior)
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{
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{
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enum TrPos { posInside, posTouch, posOutside };
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auto &faces = mesh.its.indices;
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auto &vertices = mesh.its.vertices;
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auto bb = mesh.bounding_box();
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// TODO: Parallel mode not working yet
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using exec_policy = ccr_seq;
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// Info about the needed modifications on the input mesh.
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struct MeshMods {
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// Just a thread safe wrapper for a vector of triangles.
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struct {
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std::vector<std::array<Vec3f, 3>> data;
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exec_policy::SpinningMutex mutex;
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void emplace_back(const std::array<Vec3f, 3> &pts)
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{
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std::lock_guard lk{mutex};
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data.emplace_back(pts);
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}
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size_t size() const { return data.size(); }
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const std::array<Vec3f, 3>& operator[](size_t idx) const
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{
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return data[idx];
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}
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} new_triangles;
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// A vector of bool for all faces signaling if it needs to be removed
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// or not.
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std::vector<bool> to_remove;
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MeshMods(const TriangleMesh &mesh):
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to_remove(mesh.its.indices.size(), false) {}
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// Number of triangles that need to be removed.
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size_t to_remove_cnt() const
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{
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return std::accumulate(to_remove.begin(), to_remove.end(), size_t(0));
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}
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} mesh_mods{mesh};
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// Must return true if further division of the face is needed.
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auto divfn = [&interior, bb, &mesh_mods](const DivFace &f) {
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BoundingBoxf3 facebb { f.verts.begin(), f.verts.end() };
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// Face is certainly outside the cavity
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if (! facebb.intersects(bb) && f.faceid != NEW_FACE) {
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return false;
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}
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TriangleBubble bubble{facebb.center().cast<float>(), facebb.radius()};
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double D = get_distance(bubble, interior);
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double R = bubble.R * interior.voxel_scale;
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if (std::isnan(D)) // The distance cannot be measured, triangle too big
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return true;
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// Distance of the bubble wall to the interior wall. Negative if the
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// bubble is overlapping with the interior
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double bubble_distance = D - R;
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// The face is crossing the interior or inside, it must be removed and
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// parts of it re-added, that are outside the interior
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if (bubble_distance < 0.) {
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if (f.faceid != NEW_FACE)
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mesh_mods.to_remove[f.faceid] = true;
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if (f.parent != NEW_FACE) // Top parent needs to be removed as well
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mesh_mods.to_remove[f.parent] = true;
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// If the outside part is between the interior end the exterior
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// (inside the wall being invisible), no further division is needed.
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if ((R + D) < interior.thickness)
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return false;
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return true;
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} else if (f.faceid == NEW_FACE) {
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// New face completely outside needs to be re-added.
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mesh_mods.new_triangles.emplace_back(f.verts);
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}
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return false;
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};
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interior.reset_accessor();
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exec_policy::for_each(size_t(0), faces.size(), [&] (size_t face_idx) {
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const Vec3i &face = faces[face_idx];
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std::array<Vec3f, 3> pts =
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{ vertices[face(0)], vertices[face(1)], vertices[face(2)] };
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BoundingBoxf3 facebb { pts.begin(), pts.end() };
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// Face is certainly outside the cavity
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if (! facebb.intersects(bb)) return;
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DivFace df{face, pts, long(face_idx)};
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if (divfn(df))
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divide_triangle(df, divfn);
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}, exec_policy::max_concurreny());
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auto new_faces = reserve_vector<Vec3i>(faces.size() +
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mesh_mods.new_triangles.size());
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for (size_t face_idx = 0; face_idx < faces.size(); ++face_idx) {
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if (!mesh_mods.to_remove[face_idx])
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new_faces.emplace_back(faces[face_idx]);
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}
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for(size_t i = 0; i < mesh_mods.new_triangles.size(); ++i) {
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size_t o = vertices.size();
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vertices.emplace_back(mesh_mods.new_triangles[i][0]);
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vertices.emplace_back(mesh_mods.new_triangles[i][1]);
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vertices.emplace_back(mesh_mods.new_triangles[i][2]);
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new_faces.emplace_back(int(o), int(o + 1), int(o + 2));
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}
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BOOST_LOG_TRIVIAL(info)
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<< "Trimming: " << mesh_mods.to_remove_cnt() << " triangles removed";
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BOOST_LOG_TRIVIAL(info)
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<< "Trimming: " << mesh_mods.new_triangles.size() << " triangles added";
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faces.swap(new_faces);
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new_faces = {};
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mesh = TriangleMesh{mesh.its};
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mesh.repaired = true;
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mesh.require_shared_vertices();
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}
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}
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}} // namespace Slic3r::sla
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}} // namespace Slic3r::sla
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