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TriangleMesh.cpp
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TriangleMesh.cpp
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// ----------------------------------------------------------------------------
// - Open3D: www.open3d.org -
// ----------------------------------------------------------------------------
// Copyright (c) 2018-2023 www.open3d.org
// SPDX-License-Identifier: MIT
// ----------------------------------------------------------------------------
#include "open3d/geometry/TriangleMesh.h"
#include <Eigen/Dense>
#include <numeric>
#include <queue>
#include <tuple>
#include "open3d/geometry/BoundingVolume.h"
#include "open3d/geometry/IntersectionTest.h"
#include "open3d/geometry/KDTreeFlann.h"
#include "open3d/geometry/PointCloud.h"
#include "open3d/geometry/Qhull.h"
#include "open3d/utility/Logging.h"
#include "open3d/utility/Parallel.h"
#include "open3d/utility/Random.h"
namespace open3d {
namespace geometry {
TriangleMesh &TriangleMesh::Clear() {
MeshBase::Clear();
triangles_.clear();
triangle_normals_.clear();
adjacency_list_.clear();
triangle_uvs_.clear();
materials_.clear();
triangle_material_ids_.clear();
textures_.clear();
return *this;
}
TriangleMesh &TriangleMesh::Transform(const Eigen::Matrix4d &transformation) {
MeshBase::Transform(transformation);
TransformNormals(transformation, triangle_normals_);
return *this;
}
TriangleMesh &TriangleMesh::Rotate(const Eigen::Matrix3d &R,
const Eigen::Vector3d ¢er) {
MeshBase::Rotate(R, center);
RotateNormals(R, triangle_normals_);
return *this;
}
TriangleMesh &TriangleMesh::operator+=(const TriangleMesh &mesh) {
if (mesh.IsEmpty()) return (*this);
bool add_textures = HasTriangleUvs() && HasTextures() &&
HasTriangleMaterialIds() && mesh.HasTriangleUvs() &&
mesh.HasTextures() && mesh.HasTriangleMaterialIds();
size_t old_vert_num = vertices_.size();
MeshBase::operator+=(mesh);
size_t old_tri_num = triangles_.size();
size_t add_tri_num = mesh.triangles_.size();
size_t new_tri_num = old_tri_num + add_tri_num;
if ((!HasTriangles() || HasTriangleNormals()) &&
mesh.HasTriangleNormals()) {
triangle_normals_.resize(new_tri_num);
for (size_t i = 0; i < add_tri_num; i++)
triangle_normals_[old_tri_num + i] = mesh.triangle_normals_[i];
} else {
triangle_normals_.clear();
}
triangles_.resize(triangles_.size() + mesh.triangles_.size());
Eigen::Vector3i index_shift((int)old_vert_num, (int)old_vert_num,
(int)old_vert_num);
for (size_t i = 0; i < add_tri_num; i++) {
triangles_[old_tri_num + i] = mesh.triangles_[i] + index_shift;
}
if (HasAdjacencyList()) {
ComputeAdjacencyList();
}
if (add_textures) {
size_t old_tri_uv_num = triangle_uvs_.size();
triangle_uvs_.resize(old_tri_uv_num + mesh.triangle_uvs_.size());
for (size_t i = 0; i < mesh.triangle_uvs_.size(); i++) {
triangle_uvs_[old_tri_uv_num + i] = mesh.triangle_uvs_[i];
}
size_t old_tex_num = textures_.size();
textures_.resize(old_tex_num + mesh.textures_.size());
for (size_t i = 0; i < mesh.textures_.size(); i++) {
textures_[old_tex_num + i] = mesh.textures_[i];
}
size_t old_mat_id_num = triangle_material_ids_.size();
triangle_material_ids_.resize(old_mat_id_num +
mesh.triangle_material_ids_.size());
for (size_t i = 0; i < mesh.triangle_material_ids_.size(); i++) {
triangle_material_ids_[old_mat_id_num + i] =
mesh.triangle_material_ids_[i] + (int)old_tex_num;
}
} else {
triangle_uvs_.clear();
textures_.clear();
triangle_material_ids_.clear();
}
return (*this);
}
TriangleMesh TriangleMesh::operator+(const TriangleMesh &mesh) const {
return (TriangleMesh(*this) += mesh);
}
TriangleMesh &TriangleMesh::ComputeTriangleNormals(
bool normalized /* = true*/) {
triangle_normals_.resize(triangles_.size());
for (size_t i = 0; i < triangles_.size(); i++) {
auto &triangle = triangles_[i];
Eigen::Vector3d v01 = vertices_[triangle(1)] - vertices_[triangle(0)];
Eigen::Vector3d v02 = vertices_[triangle(2)] - vertices_[triangle(0)];
triangle_normals_[i] = v01.cross(v02);
}
if (normalized) {
NormalizeNormals();
}
return *this;
}
TriangleMesh &TriangleMesh::ComputeVertexNormals(bool normalized /* = true*/) {
ComputeTriangleNormals(false);
vertex_normals_.resize(vertices_.size(), Eigen::Vector3d::Zero());
for (size_t i = 0; i < triangles_.size(); i++) {
auto &triangle = triangles_[i];
vertex_normals_[triangle(0)] += triangle_normals_[i];
vertex_normals_[triangle(1)] += triangle_normals_[i];
vertex_normals_[triangle(2)] += triangle_normals_[i];
}
if (normalized) {
NormalizeNormals();
}
return *this;
}
TriangleMesh &TriangleMesh::ComputeAdjacencyList() {
adjacency_list_.clear();
adjacency_list_.resize(vertices_.size());
for (const auto &triangle : triangles_) {
adjacency_list_[triangle(0)].insert(triangle(1));
adjacency_list_[triangle(0)].insert(triangle(2));
adjacency_list_[triangle(1)].insert(triangle(0));
adjacency_list_[triangle(1)].insert(triangle(2));
adjacency_list_[triangle(2)].insert(triangle(0));
adjacency_list_[triangle(2)].insert(triangle(1));
}
return *this;
}
std::shared_ptr<TriangleMesh> TriangleMesh::FilterSharpen(
int number_of_iterations, double strength, FilterScope scope) const {
bool filter_vertex =
scope == FilterScope::All || scope == FilterScope::Vertex;
bool filter_normal =
(scope == FilterScope::All || scope == FilterScope::Normal) &&
HasVertexNormals();
bool filter_color =
(scope == FilterScope::All || scope == FilterScope::Color) &&
HasVertexColors();
std::vector<Eigen::Vector3d> prev_vertices = vertices_;
std::vector<Eigen::Vector3d> prev_vertex_normals = vertex_normals_;
std::vector<Eigen::Vector3d> prev_vertex_colors = vertex_colors_;
std::shared_ptr<TriangleMesh> mesh = std::make_shared<TriangleMesh>();
mesh->vertices_.resize(vertices_.size());
mesh->vertex_normals_.resize(vertex_normals_.size());
mesh->vertex_colors_.resize(vertex_colors_.size());
mesh->triangles_ = triangles_;
mesh->adjacency_list_ = adjacency_list_;
if (!mesh->HasAdjacencyList()) {
mesh->ComputeAdjacencyList();
}
for (int iter = 0; iter < number_of_iterations; ++iter) {
for (size_t vidx = 0; vidx < mesh->vertices_.size(); ++vidx) {
Eigen::Vector3d vertex_sum(0, 0, 0);
Eigen::Vector3d normal_sum(0, 0, 0);
Eigen::Vector3d color_sum(0, 0, 0);
for (int nbidx : mesh->adjacency_list_[vidx]) {
if (filter_vertex) {
vertex_sum += prev_vertices[nbidx];
}
if (filter_normal) {
normal_sum += prev_vertex_normals[nbidx];
}
if (filter_color) {
color_sum += prev_vertex_colors[nbidx];
}
}
size_t nb_size = mesh->adjacency_list_[vidx].size();
if (filter_vertex) {
mesh->vertices_[vidx] =
prev_vertices[vidx] +
strength * (prev_vertices[vidx] * nb_size - vertex_sum);
}
if (filter_normal) {
mesh->vertex_normals_[vidx] =
prev_vertex_normals[vidx] +
strength * (prev_vertex_normals[vidx] * nb_size -
normal_sum);
}
if (filter_color) {
mesh->vertex_colors_[vidx] =
prev_vertex_colors[vidx] +
strength * (prev_vertex_colors[vidx] * nb_size -
color_sum);
}
}
if (iter < number_of_iterations - 1) {
std::swap(mesh->vertices_, prev_vertices);
std::swap(mesh->vertex_normals_, prev_vertex_normals);
std::swap(mesh->vertex_colors_, prev_vertex_colors);
}
}
return mesh;
}
std::shared_ptr<TriangleMesh> TriangleMesh::FilterSmoothSimple(
int number_of_iterations, FilterScope scope) const {
bool filter_vertex =
scope == FilterScope::All || scope == FilterScope::Vertex;
bool filter_normal =
(scope == FilterScope::All || scope == FilterScope::Normal) &&
HasVertexNormals();
bool filter_color =
(scope == FilterScope::All || scope == FilterScope::Color) &&
HasVertexColors();
std::vector<Eigen::Vector3d> prev_vertices = vertices_;
std::vector<Eigen::Vector3d> prev_vertex_normals = vertex_normals_;
std::vector<Eigen::Vector3d> prev_vertex_colors = vertex_colors_;
std::shared_ptr<TriangleMesh> mesh = std::make_shared<TriangleMesh>();
mesh->vertices_.resize(vertices_.size());
mesh->vertex_normals_.resize(vertex_normals_.size());
mesh->vertex_colors_.resize(vertex_colors_.size());
mesh->triangles_ = triangles_;
mesh->adjacency_list_ = adjacency_list_;
if (!mesh->HasAdjacencyList()) {
mesh->ComputeAdjacencyList();
}
for (int iter = 0; iter < number_of_iterations; ++iter) {
for (size_t vidx = 0; vidx < mesh->vertices_.size(); ++vidx) {
Eigen::Vector3d vertex_sum(0, 0, 0);
Eigen::Vector3d normal_sum(0, 0, 0);
Eigen::Vector3d color_sum(0, 0, 0);
for (int nbidx : mesh->adjacency_list_[vidx]) {
if (filter_vertex) {
vertex_sum += prev_vertices[nbidx];
}
if (filter_normal) {
normal_sum += prev_vertex_normals[nbidx];
}
if (filter_color) {
color_sum += prev_vertex_colors[nbidx];
}
}
size_t nb_size = mesh->adjacency_list_[vidx].size();
if (filter_vertex) {
mesh->vertices_[vidx] =
(prev_vertices[vidx] + vertex_sum) / (1 + nb_size);
}
if (filter_normal) {
mesh->vertex_normals_[vidx] =
(prev_vertex_normals[vidx] + normal_sum) /
(1 + nb_size);
}
if (filter_color) {
mesh->vertex_colors_[vidx] =
(prev_vertex_colors[vidx] + color_sum) / (1 + nb_size);
}
}
if (iter < number_of_iterations - 1) {
std::swap(mesh->vertices_, prev_vertices);
std::swap(mesh->vertex_normals_, prev_vertex_normals);
std::swap(mesh->vertex_colors_, prev_vertex_colors);
}
}
return mesh;
}
void TriangleMesh::FilterSmoothLaplacianHelper(
std::shared_ptr<TriangleMesh> &mesh,
const std::vector<Eigen::Vector3d> &prev_vertices,
const std::vector<Eigen::Vector3d> &prev_vertex_normals,
const std::vector<Eigen::Vector3d> &prev_vertex_colors,
const std::vector<std::unordered_set<int>> &adjacency_list,
double lambda_filter,
bool filter_vertex,
bool filter_normal,
bool filter_color) const {
for (size_t vidx = 0; vidx < mesh->vertices_.size(); ++vidx) {
Eigen::Vector3d vertex_sum(0, 0, 0);
Eigen::Vector3d normal_sum(0, 0, 0);
Eigen::Vector3d color_sum(0, 0, 0);
double total_weight = 0;
for (int nbidx : mesh->adjacency_list_[vidx]) {
auto diff = prev_vertices[vidx] - prev_vertices[nbidx];
double dist = diff.norm();
double weight = 1. / (dist + 1e-12);
total_weight += weight;
if (filter_vertex) {
vertex_sum += weight * prev_vertices[nbidx];
}
if (filter_normal) {
normal_sum += weight * prev_vertex_normals[nbidx];
}
if (filter_color) {
color_sum += weight * prev_vertex_colors[nbidx];
}
}
if (filter_vertex) {
mesh->vertices_[vidx] = prev_vertices[vidx] +
lambda_filter * (vertex_sum / total_weight -
prev_vertices[vidx]);
}
if (filter_normal) {
mesh->vertex_normals_[vidx] =
prev_vertex_normals[vidx] +
lambda_filter * (normal_sum / total_weight -
prev_vertex_normals[vidx]);
}
if (filter_color) {
mesh->vertex_colors_[vidx] =
prev_vertex_colors[vidx] +
lambda_filter * (color_sum / total_weight -
prev_vertex_colors[vidx]);
}
}
}
std::shared_ptr<TriangleMesh> TriangleMesh::FilterSmoothLaplacian(
int number_of_iterations,
double lambda_filter,
FilterScope scope) const {
bool filter_vertex =
scope == FilterScope::All || scope == FilterScope::Vertex;
bool filter_normal =
(scope == FilterScope::All || scope == FilterScope::Normal) &&
HasVertexNormals();
bool filter_color =
(scope == FilterScope::All || scope == FilterScope::Color) &&
HasVertexColors();
std::vector<Eigen::Vector3d> prev_vertices = vertices_;
std::vector<Eigen::Vector3d> prev_vertex_normals = vertex_normals_;
std::vector<Eigen::Vector3d> prev_vertex_colors = vertex_colors_;
std::shared_ptr<TriangleMesh> mesh = std::make_shared<TriangleMesh>();
mesh->vertices_.resize(vertices_.size());
mesh->vertex_normals_.resize(vertex_normals_.size());
mesh->vertex_colors_.resize(vertex_colors_.size());
mesh->triangles_ = triangles_;
mesh->adjacency_list_ = adjacency_list_;
if (!mesh->HasAdjacencyList()) {
mesh->ComputeAdjacencyList();
}
for (int iter = 0; iter < number_of_iterations; ++iter) {
FilterSmoothLaplacianHelper(mesh, prev_vertices, prev_vertex_normals,
prev_vertex_colors, mesh->adjacency_list_,
lambda_filter, filter_vertex, filter_normal,
filter_color);
if (iter < number_of_iterations - 1) {
std::swap(mesh->vertices_, prev_vertices);
std::swap(mesh->vertex_normals_, prev_vertex_normals);
std::swap(mesh->vertex_colors_, prev_vertex_colors);
}
}
return mesh;
}
std::shared_ptr<TriangleMesh> TriangleMesh::FilterSmoothTaubin(
int number_of_iterations,
double lambda_filter,
double mu,
FilterScope scope) const {
bool filter_vertex =
scope == FilterScope::All || scope == FilterScope::Vertex;
bool filter_normal =
(scope == FilterScope::All || scope == FilterScope::Normal) &&
HasVertexNormals();
bool filter_color =
(scope == FilterScope::All || scope == FilterScope::Color) &&
HasVertexColors();
std::vector<Eigen::Vector3d> prev_vertices = vertices_;
std::vector<Eigen::Vector3d> prev_vertex_normals = vertex_normals_;
std::vector<Eigen::Vector3d> prev_vertex_colors = vertex_colors_;
std::shared_ptr<TriangleMesh> mesh = std::make_shared<TriangleMesh>();
mesh->vertices_.resize(vertices_.size());
mesh->vertex_normals_.resize(vertex_normals_.size());
mesh->vertex_colors_.resize(vertex_colors_.size());
mesh->triangles_ = triangles_;
mesh->adjacency_list_ = adjacency_list_;
if (!mesh->HasAdjacencyList()) {
mesh->ComputeAdjacencyList();
}
for (int iter = 0; iter < number_of_iterations; ++iter) {
FilterSmoothLaplacianHelper(mesh, prev_vertices, prev_vertex_normals,
prev_vertex_colors, mesh->adjacency_list_,
lambda_filter, filter_vertex, filter_normal,
filter_color);
std::swap(mesh->vertices_, prev_vertices);
std::swap(mesh->vertex_normals_, prev_vertex_normals);
std::swap(mesh->vertex_colors_, prev_vertex_colors);
FilterSmoothLaplacianHelper(mesh, prev_vertices, prev_vertex_normals,
prev_vertex_colors, mesh->adjacency_list_,
mu, filter_vertex, filter_normal,
filter_color);
if (iter < number_of_iterations - 1) {
std::swap(mesh->vertices_, prev_vertices);
std::swap(mesh->vertex_normals_, prev_vertex_normals);
std::swap(mesh->vertex_colors_, prev_vertex_colors);
}
}
return mesh;
}
std::shared_ptr<PointCloud> TriangleMesh::SamplePointsUniformlyImpl(
size_t number_of_points,
const std::vector<double> &triangle_areas,
bool use_triangle_normal) {
utility::random::DiscreteGenerator<size_t> triangle_index_generator(
triangle_areas.begin(), triangle_areas.end());
// sample point cloud
bool has_vert_normal = HasVertexNormals();
bool has_vert_color = HasVertexColors();
utility::random::UniformRealGenerator<double> uniform_generator(0.0, 1.0);
auto pcd = std::make_shared<PointCloud>();
pcd->points_.resize(number_of_points);
if (has_vert_normal || use_triangle_normal) {
pcd->normals_.resize(number_of_points);
}
if (use_triangle_normal && !HasTriangleNormals()) {
ComputeTriangleNormals(true);
}
if (has_vert_color) {
pcd->colors_.resize(number_of_points);
}
for (size_t point_idx = 0; point_idx < number_of_points; ++point_idx) {
double r1 = uniform_generator();
double r2 = uniform_generator();
double a = (1 - std::sqrt(r1));
double b = std::sqrt(r1) * (1 - r2);
double c = std::sqrt(r1) * r2;
size_t tidx = triangle_index_generator();
const Eigen::Vector3i &triangle = triangles_[tidx];
pcd->points_[point_idx] = a * vertices_[triangle(0)] +
b * vertices_[triangle(1)] +
c * vertices_[triangle(2)];
if (has_vert_normal && !use_triangle_normal) {
pcd->normals_[point_idx] = a * vertex_normals_[triangle(0)] +
b * vertex_normals_[triangle(1)] +
c * vertex_normals_[triangle(2)];
}
if (use_triangle_normal) {
pcd->normals_[point_idx] = triangle_normals_[tidx];
}
if (has_vert_color) {
pcd->colors_[point_idx] = a * vertex_colors_[triangle(0)] +
b * vertex_colors_[triangle(1)] +
c * vertex_colors_[triangle(2)];
}
}
return pcd;
}
std::shared_ptr<PointCloud> TriangleMesh::SamplePointsUniformly(
size_t number_of_points, bool use_triangle_normal /* = false */) {
if (number_of_points <= 0) {
utility::LogError("number_of_points <= 0");
}
if (triangles_.size() == 0) {
utility::LogError("Input mesh has no triangles.");
}
// Compute area of each triangle
std::vector<double> triangle_areas;
GetSurfaceArea(triangle_areas);
return SamplePointsUniformlyImpl(number_of_points, triangle_areas,
use_triangle_normal);
}
std::shared_ptr<PointCloud> TriangleMesh::SamplePointsPoissonDisk(
size_t number_of_points,
double init_factor /* = 5 */,
const std::shared_ptr<PointCloud> pcl_init /* = nullptr */,
bool use_triangle_normal /* = false */) {
if (number_of_points <= 0) {
utility::LogError("number_of_points <= 0");
}
if (triangles_.size() == 0) {
utility::LogError("Input mesh has no triangles.");
}
if (pcl_init == nullptr && init_factor < 1) {
utility::LogError(
"Either pass pcl_init with #points > number_of_points or "
"init_factor > 1");
}
if (pcl_init != nullptr && pcl_init->points_.size() < number_of_points) {
utility::LogError(
"Either pass pcl_init with #points > number_of_points, or "
"init_factor > 1");
}
// Compute area of each triangle and sum surface area
std::vector<double> triangle_areas;
double surface_area = GetSurfaceArea(triangle_areas);
// Compute init points using uniform sampling
std::shared_ptr<PointCloud> pcl;
if (pcl_init == nullptr) {
pcl = SamplePointsUniformlyImpl(size_t(init_factor * number_of_points),
triangle_areas, use_triangle_normal);
} else {
pcl = std::make_shared<PointCloud>();
pcl->points_ = pcl_init->points_;
pcl->normals_ = pcl_init->normals_;
pcl->colors_ = pcl_init->colors_;
}
// Set-up sample elimination
double alpha = 8; // constant defined in paper
double beta = 0.65; // constant defined in paper
double gamma = 1.5; // constant defined in paper
double ratio = double(number_of_points) / double(pcl->points_.size());
double r_max = 2 * std::sqrt((surface_area / number_of_points) /
(2 * std::sqrt(3.)));
double r_min = r_max * beta * (1 - std::pow(ratio, gamma));
std::vector<double> weights(pcl->points_.size());
std::vector<bool> deleted(pcl->points_.size(), false);
KDTreeFlann kdtree(*pcl);
auto WeightFcn = [&](double d2) {
double d = std::sqrt(d2);
if (d < r_min) {
d = r_min;
}
return std::pow(1 - d / r_max, alpha);
};
auto ComputePointWeight = [&](int pidx0) {
std::vector<int> nbs;
std::vector<double> dists2;
kdtree.SearchRadius(pcl->points_[pidx0], r_max, nbs, dists2);
double weight = 0;
for (size_t nbidx = 0; nbidx < nbs.size(); ++nbidx) {
int pidx1 = nbs[nbidx];
// only count weights if not the same point if not deleted
if (pidx0 == pidx1 || deleted[pidx1]) {
continue;
}
weight += WeightFcn(dists2[nbidx]);
}
weights[pidx0] = weight;
};
// init weights and priority queue
typedef std::tuple<int, double> QueueEntry;
auto WeightCmp = [](const QueueEntry &a, const QueueEntry &b) {
return std::get<1>(a) < std::get<1>(b);
};
std::priority_queue<QueueEntry, std::vector<QueueEntry>,
decltype(WeightCmp)>
queue(WeightCmp);
for (size_t pidx0 = 0; pidx0 < pcl->points_.size(); ++pidx0) {
ComputePointWeight(int(pidx0));
queue.push(QueueEntry(int(pidx0), weights[pidx0]));
};
// sample elimination
size_t current_number_of_points = pcl->points_.size();
while (current_number_of_points > number_of_points) {
int pidx;
double weight;
std::tie(pidx, weight) = queue.top();
queue.pop();
// test if the entry is up to date (because of reinsert)
if (deleted[pidx] || weight != weights[pidx]) {
continue;
}
// delete current sample
deleted[pidx] = true;
current_number_of_points--;
// update weights
std::vector<int> nbs;
std::vector<double> dists2;
kdtree.SearchRadius(pcl->points_[pidx], r_max, nbs, dists2);
for (int nb : nbs) {
ComputePointWeight(nb);
queue.push(QueueEntry(nb, weights[nb]));
}
}
// update pcl
bool has_vert_normal = pcl->HasNormals();
bool has_vert_color = pcl->HasColors();
int next_free = 0;
for (size_t idx = 0; idx < pcl->points_.size(); ++idx) {
if (!deleted[idx]) {
pcl->points_[next_free] = pcl->points_[idx];
if (has_vert_normal) {
pcl->normals_[next_free] = pcl->normals_[idx];
}
if (has_vert_color) {
pcl->colors_[next_free] = pcl->colors_[idx];
}
next_free++;
}
}
pcl->points_.resize(next_free);
if (has_vert_normal) {
pcl->normals_.resize(next_free);
}
if (has_vert_color) {
pcl->colors_.resize(next_free);
}
return pcl;
}
TriangleMesh &TriangleMesh::RemoveDuplicatedVertices() {
typedef std::tuple<double, double, double> Coordinate3;
std::unordered_map<Coordinate3, size_t, utility::hash_tuple<Coordinate3>>
point_to_old_index;
std::vector<int> index_old_to_new(vertices_.size());
bool has_vert_normal = HasVertexNormals();
bool has_vert_color = HasVertexColors();
size_t old_vertex_num = vertices_.size();
size_t k = 0; // new index
for (size_t i = 0; i < old_vertex_num; i++) { // old index
Coordinate3 coord = std::make_tuple(vertices_[i](0), vertices_[i](1),
vertices_[i](2));
if (point_to_old_index.find(coord) == point_to_old_index.end()) {
point_to_old_index[coord] = i;
vertices_[k] = vertices_[i];
if (has_vert_normal) vertex_normals_[k] = vertex_normals_[i];
if (has_vert_color) vertex_colors_[k] = vertex_colors_[i];
index_old_to_new[i] = (int)k;
k++;
} else {
index_old_to_new[i] = index_old_to_new[point_to_old_index[coord]];
}
}
vertices_.resize(k);
if (has_vert_normal) vertex_normals_.resize(k);
if (has_vert_color) vertex_colors_.resize(k);
if (k < old_vertex_num) {
for (auto &triangle : triangles_) {
triangle(0) = index_old_to_new[triangle(0)];
triangle(1) = index_old_to_new[triangle(1)];
triangle(2) = index_old_to_new[triangle(2)];
}
if (HasAdjacencyList()) {
ComputeAdjacencyList();
}
}
utility::LogDebug(
"[RemoveDuplicatedVertices] {:d} vertices have been removed.",
(int)(old_vertex_num - k));
return *this;
}
TriangleMesh &TriangleMesh::RemoveDuplicatedTriangles() {
if (HasTriangleUvs()) {
utility::LogWarning(
"[RemoveDuplicatedTriangles] This mesh contains triangle uvs "
"that are not handled in this function");
}
typedef std::tuple<int, int, int> Index3;
std::unordered_map<Index3, size_t, utility::hash_tuple<Index3>>
triangle_to_old_index;
bool has_tri_normal = HasTriangleNormals();
size_t old_triangle_num = triangles_.size();
size_t k = 0;
for (size_t i = 0; i < old_triangle_num; i++) {
Index3 index;
// We first need to find the minimum index. Because triangle (0-1-2)
// and triangle (2-0-1) are the same.
if (triangles_[i](0) <= triangles_[i](1)) {
if (triangles_[i](0) <= triangles_[i](2)) {
index = std::make_tuple(triangles_[i](0), triangles_[i](1),
triangles_[i](2));
} else {
index = std::make_tuple(triangles_[i](2), triangles_[i](0),
triangles_[i](1));
}
} else {
if (triangles_[i](1) <= triangles_[i](2)) {
index = std::make_tuple(triangles_[i](1), triangles_[i](2),
triangles_[i](0));
} else {
index = std::make_tuple(triangles_[i](2), triangles_[i](0),
triangles_[i](1));
}
}
if (triangle_to_old_index.find(index) == triangle_to_old_index.end()) {
triangle_to_old_index[index] = i;
triangles_[k] = triangles_[i];
if (has_tri_normal) triangle_normals_[k] = triangle_normals_[i];
k++;
}
}
triangles_.resize(k);
if (has_tri_normal) triangle_normals_.resize(k);
if (k < old_triangle_num && HasAdjacencyList()) {
ComputeAdjacencyList();
}
utility::LogDebug(
"[RemoveDuplicatedTriangles] {:d} triangles have been removed.",
(int)(old_triangle_num - k));
return *this;
}
TriangleMesh &TriangleMesh::RemoveUnreferencedVertices() {
std::vector<bool> vertex_has_reference(vertices_.size(), false);
for (const auto &triangle : triangles_) {
vertex_has_reference[triangle(0)] = true;
vertex_has_reference[triangle(1)] = true;
vertex_has_reference[triangle(2)] = true;
}
std::vector<int> index_old_to_new(vertices_.size());
bool has_vert_normal = HasVertexNormals();
bool has_vert_color = HasVertexColors();
size_t old_vertex_num = vertices_.size();
size_t k = 0; // new index
for (size_t i = 0; i < old_vertex_num; i++) { // old index
if (vertex_has_reference[i]) {
vertices_[k] = vertices_[i];
if (has_vert_normal) vertex_normals_[k] = vertex_normals_[i];
if (has_vert_color) vertex_colors_[k] = vertex_colors_[i];
index_old_to_new[i] = (int)k;
k++;
} else {
index_old_to_new[i] = -1;
}
}
vertices_.resize(k);
if (has_vert_normal) vertex_normals_.resize(k);
if (has_vert_color) vertex_colors_.resize(k);
if (k < old_vertex_num) {
for (auto &triangle : triangles_) {
triangle(0) = index_old_to_new[triangle(0)];
triangle(1) = index_old_to_new[triangle(1)];
triangle(2) = index_old_to_new[triangle(2)];
}
if (HasAdjacencyList()) {
ComputeAdjacencyList();
}
}
utility::LogDebug(
"[RemoveUnreferencedVertices] {:d} vertices have been removed.",
(int)(old_vertex_num - k));
return *this;
}
TriangleMesh &TriangleMesh::RemoveDegenerateTriangles() {
if (HasTriangleUvs()) {
utility::LogWarning(
"[RemoveDegenerateTriangles] This mesh contains triangle uvs "
"that are not handled in this function");
}
bool has_tri_normal = HasTriangleNormals();
size_t old_triangle_num = triangles_.size();
size_t k = 0;
for (size_t i = 0; i < old_triangle_num; i++) {
const auto &triangle = triangles_[i];
if (triangle(0) != triangle(1) && triangle(1) != triangle(2) &&
triangle(2) != triangle(0)) {
triangles_[k] = triangles_[i];
if (has_tri_normal) triangle_normals_[k] = triangle_normals_[i];
k++;
}
}
triangles_.resize(k);
if (has_tri_normal) triangle_normals_.resize(k);
if (k < old_triangle_num && HasAdjacencyList()) {
ComputeAdjacencyList();
}
utility::LogDebug(
"[RemoveDegenerateTriangles] {:d} triangles have been "
"removed.",
(int)(old_triangle_num - k));
return *this;
}
TriangleMesh &TriangleMesh::RemoveNonManifoldEdges() {
if (HasTriangleUvs()) {
utility::LogWarning(
"[RemoveNonManifoldEdges] This mesh contains triangle uvs that "
"are not handled in this function");
}
std::vector<double> triangle_areas;
GetSurfaceArea(triangle_areas);
bool mesh_is_edge_manifold = false;
while (!mesh_is_edge_manifold) {
mesh_is_edge_manifold = true;
auto edges_to_triangles = GetEdgeToTrianglesMap();
for (auto &kv : edges_to_triangles) {
size_t n_edge_triangle_refs = kv.second.size();
// check if the given edge is manifold
// (has exactly 1, or 2 adjacent triangles)
if (n_edge_triangle_refs == 1u || n_edge_triangle_refs == 2u) {
continue;
}
// There is at least one edge that is non-manifold
mesh_is_edge_manifold = false;
// if the edge is non-manifold, then check if a referenced
// triangle has already been removed
// (triangle area has been set to < 0), otherwise remove triangle
// with smallest surface area until number of adjacent triangles
// is <= 2.
// 1) count triangles that are not marked deleted
int n_triangles = 0;
for (int tidx : kv.second) {
if (triangle_areas[tidx] > 0) {
n_triangles++;
}
}
// 2) mark smallest triangles as deleted by setting
// surface area to -1
int n_triangles_to_delete = n_triangles - 2;
while (n_triangles_to_delete > 0) {
// find triangle with smallest area
int min_tidx = -1;
double min_area = std::numeric_limits<double>::max();
for (int tidx : kv.second) {
double area = triangle_areas[tidx];
if (area > 0 && area < min_area) {
min_tidx = tidx;
min_area = area;
}
}
// mark triangle as deleted by setting area to -1
triangle_areas[min_tidx] = -1;
n_triangles_to_delete--;
}
}
// delete marked triangles
bool has_tri_normal = HasTriangleNormals();
int to_tidx = 0;
for (size_t from_tidx = 0; from_tidx < triangles_.size(); ++from_tidx) {
if (triangle_areas[from_tidx] > 0) {
triangles_[to_tidx] = triangles_[from_tidx];
triangle_areas[to_tidx] = triangle_areas[from_tidx];
if (has_tri_normal) {
triangle_normals_[to_tidx] = triangle_normals_[from_tidx];
}
to_tidx++;
}
}
triangles_.resize(to_tidx);
triangle_areas.resize(to_tidx);
if (has_tri_normal) {
triangle_normals_.resize(to_tidx);
}
}
return *this;
}
TriangleMesh &TriangleMesh::MergeCloseVertices(double eps) {
KDTreeFlann kdtree(*this);
// precompute all neighbours
utility::LogDebug("Precompute Neighbours");
std::vector<std::vector<int>> nbs(vertices_.size());
#pragma omp parallel for schedule(static) \
num_threads(utility::EstimateMaxThreads())
for (int idx = 0; idx < int(vertices_.size()); ++idx) {
std::vector<double> dists2;
kdtree.SearchRadius(vertices_[idx], eps, nbs[idx], dists2);
}
utility::LogDebug("Done Precompute Neighbours");
bool has_vertex_normals = HasVertexNormals();
bool has_vertex_colors = HasVertexColors();
std::vector<Eigen::Vector3d> new_vertices;
std::vector<Eigen::Vector3d> new_vertex_normals;
std::vector<Eigen::Vector3d> new_vertex_colors;
std::unordered_map<int, int> new_vert_mapping;
for (int vidx = 0; vidx < int(vertices_.size()); ++vidx) {
if (new_vert_mapping.count(vidx) > 0) {
continue;
}
int new_vidx = int(new_vertices.size());
new_vert_mapping[vidx] = new_vidx;
Eigen::Vector3d vertex = vertices_[vidx];
Eigen::Vector3d normal{0, 0, 0};
if (has_vertex_normals) {
normal = vertex_normals_[vidx];
}
Eigen::Vector3d color{0, 0, 0};
if (has_vertex_colors) {
color = vertex_colors_[vidx];
}
int n = 1;
for (int nb : nbs[vidx]) {
if (vidx == nb || new_vert_mapping.count(nb) > 0) {
continue;
}
vertex += vertices_[nb];
if (has_vertex_normals) {
normal += vertex_normals_[nb];
}
if (has_vertex_colors) {
color += vertex_colors_[nb];
}
new_vert_mapping[nb] = new_vidx;
n += 1;
}
new_vertices.push_back(vertex / n);
if (has_vertex_normals) {
new_vertex_normals.push_back(normal / n);
}
if (has_vertex_colors) {
new_vertex_colors.push_back(color / n);
}
}
utility::LogDebug("Merged {} vertices",
vertices_.size() - new_vertices.size());
std::swap(vertices_, new_vertices);
std::swap(vertex_normals_, new_vertex_normals);
std::swap(vertex_colors_, new_vertex_colors);
for (auto &triangle : triangles_) {
triangle(0) = new_vert_mapping[triangle(0)];
triangle(1) = new_vert_mapping[triangle(1)];
triangle(2) = new_vert_mapping[triangle(2)];
}
if (HasTriangleNormals()) {
ComputeTriangleNormals();
}
return *this;
}
template <typename F>
bool OrientTriangleHelper(const std::vector<Eigen::Vector3i> &triangles,
F &swap) {
std::unordered_map<Eigen::Vector2i, Eigen::Vector2i,
utility::hash_eigen<Eigen::Vector2i>>
edge_to_orientation;
std::unordered_set<int> unvisited_triangles;
std::unordered_map<Eigen::Vector2i, std::unordered_set<int>,
utility::hash_eigen<Eigen::Vector2i>>
adjacent_triangles;
std::queue<int> triangle_queue;
auto VerifyAndAdd = [&](int vidx0, int vidx1) {
Eigen::Vector2i key = TriangleMesh::GetOrderedEdge(vidx0, vidx1);
if (edge_to_orientation.count(key) > 0) {
if (edge_to_orientation.at(key)(0) == vidx0) {
return false;
}
} else {
edge_to_orientation[key] = Eigen::Vector2i(vidx0, vidx1);
}
return true;
};
auto AddTriangleNbsToQueue = [&](const Eigen::Vector2i &edge) {
for (int nb_tidx : adjacent_triangles[edge]) {
triangle_queue.push(nb_tidx);
}
};