72 lines
3.0 KiB
C++
72 lines
3.0 KiB
C++
#include "TriangleSetSampling.hpp"
|
|
#include <map>
|
|
#include <random>
|
|
#include <tbb/parallel_for.h>
|
|
#include <tbb/blocked_range.h>
|
|
|
|
namespace Slic3r {
|
|
|
|
TriangleSetSamples sample_its_uniform_parallel(size_t samples_count, const indexed_triangle_set &triangle_set) {
|
|
std::vector<double> triangles_area(triangle_set.indices.size());
|
|
|
|
tbb::parallel_for(tbb::blocked_range<size_t>(0, triangle_set.indices.size()),
|
|
[&triangle_set, &triangles_area](
|
|
tbb::blocked_range<size_t> r) {
|
|
for (size_t t_idx = r.begin(); t_idx < r.end(); ++t_idx) {
|
|
const Vec3f &a = triangle_set.vertices[triangle_set.indices[t_idx].x()];
|
|
const Vec3f &b = triangle_set.vertices[triangle_set.indices[t_idx].y()];
|
|
const Vec3f &c = triangle_set.vertices[triangle_set.indices[t_idx].z()];
|
|
double area = double(0.5 * (b - a).cross(c - a).norm());
|
|
triangles_area[t_idx] = area;
|
|
}
|
|
});
|
|
|
|
std::map<double, size_t> area_sum_to_triangle_idx;
|
|
float area_sum = 0;
|
|
for (size_t t_idx = 0; t_idx < triangles_area.size(); ++t_idx) {
|
|
area_sum += triangles_area[t_idx];
|
|
area_sum_to_triangle_idx[area_sum] = t_idx;
|
|
}
|
|
|
|
std::mt19937_64 mersenne_engine { 27644437 };
|
|
// random numbers on interval [0, 1)
|
|
std::uniform_real_distribution<double> fdistribution;
|
|
|
|
auto get_random = [&fdistribution, &mersenne_engine]() {
|
|
return Vec3d { fdistribution(mersenne_engine), fdistribution(mersenne_engine), fdistribution(mersenne_engine) };
|
|
};
|
|
|
|
std::vector<Vec3d> random_samples(samples_count);
|
|
std::generate(random_samples.begin(), random_samples.end(), get_random);
|
|
|
|
TriangleSetSamples result;
|
|
result.total_area = area_sum;
|
|
result.positions.resize(samples_count);
|
|
result.normals.resize(samples_count);
|
|
result.triangle_indices.resize(samples_count);
|
|
|
|
tbb::parallel_for(tbb::blocked_range<size_t>(0, samples_count),
|
|
[&triangle_set, &area_sum_to_triangle_idx, &area_sum, &random_samples, &result](
|
|
tbb::blocked_range<size_t> r) {
|
|
for (size_t s_idx = r.begin(); s_idx < r.end(); ++s_idx) {
|
|
double t_sample = random_samples[s_idx].x() * area_sum;
|
|
size_t t_idx = area_sum_to_triangle_idx.upper_bound(t_sample)->second;
|
|
|
|
double sq_u = std::sqrt(random_samples[s_idx].y());
|
|
double v = random_samples[s_idx].z();
|
|
|
|
Vec3f A = triangle_set.vertices[triangle_set.indices[t_idx].x()];
|
|
Vec3f B = triangle_set.vertices[triangle_set.indices[t_idx].y()];
|
|
Vec3f C = triangle_set.vertices[triangle_set.indices[t_idx].z()];
|
|
|
|
result.positions[s_idx] = A * (1 - sq_u) + B * (sq_u * (1 - v)) + C * (v * sq_u);
|
|
result.normals[s_idx] = ((B - A).cross(C - B)).normalized();
|
|
result.triangle_indices[s_idx] = t_idx;
|
|
}
|
|
});
|
|
|
|
return result;
|
|
}
|
|
|
|
}
|