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OrcaSlicer/src/libslic3r/SLA/SLAAutoSupports.cpp

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#include "igl/random_points_on_mesh.h"
#include "igl/AABB.h"
#include <tbb/parallel_for.h>
#include "SLAAutoSupports.hpp"
#include "Model.hpp"
#include "ExPolygon.hpp"
#include "SVG.hpp"
#include "Point.hpp"
#include "ClipperUtils.hpp"
#include "Tesselate.hpp"
#include "libslic3r.h"
#include <iostream>
#include <random>
namespace Slic3r {
/*float SLAAutoSupports::approximate_geodesic_distance(const Vec3d& p1, const Vec3d& p2, Vec3d& n1, Vec3d& n2)
{
n1.normalize();
n2.normalize();
Vec3d v = (p2-p1);
v.normalize();
float c1 = n1.dot(v);
float c2 = n2.dot(v);
float result = pow(p1(0)-p2(0), 2) + pow(p1(1)-p2(1), 2) + pow(p1(2)-p2(2), 2);
// Check for division by zero:
if(fabs(c1 - c2) > 0.0001)
result *= (asin(c1) - asin(c2)) / (c1 - c2);
return result;
}
float SLAAutoSupports::get_required_density(float angle) const
{
// calculation would be density_0 * cos(angle). To provide one more degree of freedom, we will scale the angle
// to get the user-set density for 45 deg. So it ends up as density_0 * cos(K * angle).
float K = 4.f * float(acos(m_config.density_at_45/m_config.density_at_horizontal) / M_PI);
return std::max(0.f, float(m_config.density_at_horizontal * cos(K*angle)));
}
float SLAAutoSupports::distance_limit(float angle) const
{
return 1./(2.4*get_required_density(angle));
}*/
SLAAutoSupports::SLAAutoSupports(const TriangleMesh& mesh, const sla::EigenMesh3D& emesh, const std::vector<ExPolygons>& slices, const std::vector<float>& heights,
const Config& config, std::function<void(void)> throw_on_cancel)
: m_config(config), m_emesh(emesh), m_throw_on_cancel(throw_on_cancel)
{
process(slices, heights);
project_onto_mesh(m_output);
}
void SLAAutoSupports::project_onto_mesh(std::vector<sla::SupportPoint>& points) const
{
// The function makes sure that all the points are really exactly placed on the mesh.
igl::Hit hit_up{0, 0, 0.f, 0.f, 0.f};
igl::Hit hit_down{0, 0, 0.f, 0.f, 0.f};
// Use a reasonable granularity to account for the worker thread synchronization cost.
tbb::parallel_for(tbb::blocked_range<size_t>(0, points.size(), 64),
[this, &points](const tbb::blocked_range<size_t>& range) {
for (size_t point_id = range.begin(); point_id < range.end(); ++ point_id) {
if ((point_id % 16) == 0)
// Don't call the following function too often as it flushes CPU write caches due to synchronization primitves.
m_throw_on_cancel();
Vec3f& p = points[point_id].pos;
// Project the point upward and downward and choose the closer intersection with the mesh.
//bool up = igl::ray_mesh_intersect(p.cast<float>(), Vec3f(0., 0., 1.), m_V, m_F, hit_up);
//bool down = igl::ray_mesh_intersect(p.cast<float>(), Vec3f(0., 0., -1.), m_V, m_F, hit_down);
sla::EigenMesh3D::hit_result hit_up = m_emesh.query_ray_hit(p.cast<double>(), Vec3d(0., 0., 1.));
sla::EigenMesh3D::hit_result hit_down = m_emesh.query_ray_hit(p.cast<double>(), Vec3d(0., 0., -1.));
bool up = hit_up.face() != -1;
bool down = hit_down.face() != -1;
if (!up && !down)
continue;
sla::EigenMesh3D::hit_result& hit = (!down || (hit_up.distance() < hit_down.distance())) ? hit_up : hit_down;
//int fid = hit.face();
//Vec3f bc(1-hit.u-hit.v, hit.u, hit.v);
//p = (bc(0) * m_V.row(m_F(fid, 0)) + bc(1) * m_V.row(m_F(fid, 1)) + bc(2)*m_V.row(m_F(fid, 2))).cast<float>();
p = p + (hit.distance() * hit.direction()).cast<float>();
}
});
}
void SLAAutoSupports::process(const std::vector<ExPolygons>& slices, const std::vector<float>& heights)
{
std::vector<std::pair<ExPolygon, coord_t>> islands;
std::vector<Structure> structures_old;
std::vector<Structure> structures_new;
for (unsigned int i = 0; i<slices.size(); ++i) {
const ExPolygons& expolys_top = slices[i];
//FIXME WTF?
const float height = (i>2 ? heights[i-3] : heights[0]-(heights[1]-heights[0]));
const float layer_height = (i!=0 ? heights[i]-heights[i-1] : heights[0]);
const float safe_angle = 5.f * (float(M_PI)/180.f); // smaller number - less supports
const float between_layers_offset = float(scale_(layer_height / std::tan(safe_angle)));
// FIXME: calculate actual pixel area from printer config:
//const float pixel_area = pow(wxGetApp().preset_bundle->project_config.option<ConfigOptionFloat>("display_width") / wxGetApp().preset_bundle->project_config.option<ConfigOptionInt>("display_pixels_x"), 2.f); //
const float pixel_area = pow(0.047f, 2.f);
// Check all ExPolygons on this slice and check whether they are new or belonging to something below.
for (const ExPolygon& polygon : expolys_top) {
float area = float(polygon.area() * SCALING_FACTOR * SCALING_FACTOR);
if (area < pixel_area)
continue;
//FIXME this is not a correct centroid of a polygon with holes.
structures_new.emplace_back(polygon, get_extents(polygon.contour), Slic3r::unscale(polygon.contour.centroid()).cast<float>(), area, height);
Structure& top = structures_new.back();
//FIXME This has a quadratic time complexity, it will be excessively slow for many tiny islands.
// At least it is now using a bounding box check for pre-filtering.
for (Structure& bottom : structures_old)
if (top.overlaps(bottom)) {
top.structures_below.push_back(&bottom);
float centroids_dist = (bottom.centroid - top.centroid).norm();
// Penalization resulting from centroid offset:
// bottom.supports_force *= std::min(1.f, 1.f - std::min(1.f, (1600.f * layer_height) * centroids_dist * centroids_dist / bottom.area));
bottom.supports_force *= std::min(1.f, 1.f - std::min(1.f, 80.f * centroids_dist * centroids_dist / bottom.area));
// Penalization resulting from increasing polygon area:
bottom.supports_force *= std::min(1.f, 20.f * bottom.area / top.area);
}
}
// Let's assign proper support force to each of them:
for (const Structure& below : structures_old) {
std::vector<Structure*> above_list;
float above_area = 0.f;
for (Structure& new_str : structures_new)
for (const Structure* below1 : new_str.structures_below)
if (&below == below1) {
above_list.push_back(&new_str);
above_area += above_list.back()->area;
}
for (Structure* above : above_list)
above->supports_force += below.supports_force * above->area / above_area;
}
// Now iterate over all polygons and append new points if needed.
for (Structure& s : structures_new) {
if (s.structures_below.empty()) // completely new island - needs support no doubt
uniformly_cover(*s.polygon, s, true);
else
// Let's see if there's anything that overlaps enough to need supports:
// What we now have in polygons needs support, regardless of what the forces are, so we can add them.
for (const ExPolygon& p : diff_ex(to_polygons(*s.polygon), offset(s.expolygons_below(), between_layers_offset)))
//FIXME is it an island point or not? Vojtech thinks it is.
uniformly_cover(p, s);
}
// We should also check if current support is enough given the polygon area.
for (Structure& s : structures_new) {
// Areas not supported by the areas below.
ExPolygons e = diff_ex(to_polygons(*s.polygon), s.polygons_below());
float e_area = 0.f;
for (const ExPolygon &ex : e)
e_area += float(ex.area());
// Penalization resulting from large diff from the last layer:
// s.supports_force /= std::max(1.f, (layer_height / 0.3f) * e_area / s.area);
s.supports_force /= std::max(1.f, 0.17f * (e_area * float(SCALING_FACTOR * SCALING_FACTOR)) / s.area);
if (s.area * m_config.tear_pressure > s.supports_force) {
//FIXME Don't calculate area inside the compare function!
//FIXME Cover until the force deficit is covered. Cover multiple areas, sort by decreasing area.
ExPolygons::iterator largest_it = std::max_element(e.begin(), e.end(), [](const ExPolygon& a, const ExPolygon& b) { return a.area() < b.area(); });
if (!e.empty())
//FIXME add the support force deficit as a parameter, only cover until the defficiency is covered.
uniformly_cover(*largest_it, s);
}
}
// All is done. Prepare to advance to the next layer.
structures_old = std::move(structures_new);
structures_new.clear();
m_throw_on_cancel();
#ifdef SLA_AUTOSUPPORTS_DEBUG
/*std::string layer_num_str = std::string((i<10 ? "0" : "")) + std::string((i<100 ? "0" : "")) + std::to_string(i);
output_expolygons(expolys_top, "top" + layer_num_str + ".svg");
output_expolygons(diff, "diff" + layer_num_str + ".svg");
if (!islands.empty())
output_expolygons(islands, "islands" + layer_num_str + ".svg");*/
#endif /* SLA_AUTOSUPPORTS_DEBUG */
}
}
std::vector<Vec2f> sample_expolygon(const ExPolygon &expoly, float samples_per_mm2, std::mt19937 &rng)
{
// Triangulate the polygon with holes into triplets of 3D points.
std::vector<Vec2f> triangles = Slic3r::triangulate_expolygon_2f(expoly);
std::vector<Vec2f> out;
if (! triangles.empty())
{
// Calculate area of each triangle.
std::vector<float> areas;
areas.reserve(triangles.size() / 3);
for (size_t i = 0; i < triangles.size(); ) {
const Vec2f &a = triangles[i ++];
const Vec2f v1 = triangles[i ++] - a;
const Vec2f v2 = triangles[i ++] - a;
areas.emplace_back(0.5f * std::abs(cross2(v1, v2)));
if (i != 3)
// Prefix sum of the areas.
areas.back() += areas[areas.size() - 2];
}
size_t num_samples = size_t(ceil(areas.back() * samples_per_mm2));
std::uniform_real_distribution<> random_triangle(0., double(areas.back()));
std::uniform_real_distribution<> random_float(0., 1.);
for (size_t i = 0; i < num_samples; ++ i) {
double r = random_triangle(rng);
size_t idx_triangle = std::min<size_t>(std::upper_bound(areas.begin(), areas.end(), (float)r) - areas.begin(), areas.size() - 1) * 3;
// Select a random point on the triangle.
double u = float(sqrt(random_float(rng)));
double v = float(random_float(rng));
const Vec2f &a = triangles[idx_triangle ++];
const Vec2f &b = triangles[idx_triangle++];
const Vec2f &c = triangles[idx_triangle];
const Vec2f x = a * (1.f - u) + b * (u * (1.f - v)) + c * (v * u);
out.emplace_back(x);
}
}
return out;
}
std::vector<Vec2f> sample_expolygon_with_boundary(const ExPolygon &expoly, float samples_per_mm2, float samples_per_mm_boundary, std::mt19937 &rng)
{
std::vector<Vec2f> out = sample_expolygon(expoly, samples_per_mm2, rng);
double point_stepping_scaled = scale_(1.f) / samples_per_mm_boundary;
for (size_t i_contour = 0; i_contour <= expoly.holes.size(); ++ i_contour) {
const Polygon &contour = (i_contour == 0) ? expoly.contour : expoly.holes[i_contour - 1];
const Points pts = contour.equally_spaced_points(point_stepping_scaled);
for (size_t i = 0; i < pts.size(); ++ i)
out.emplace_back(unscale<float>(pts[i].x()), unscale<float>(pts[i].y()));
}
return out;
}
std::vector<Vec2f> poisson_disk_from_samples(const std::vector<Vec2f> &raw_samples, float radius)
{
Vec2f corner_min(FLT_MAX, FLT_MAX);
for (const Vec2f &pt : raw_samples) {
corner_min.x() = std::min(corner_min.x(), pt.x());
corner_min.y() = std::min(corner_min.y(), pt.y());
}
// Assign the raw samples to grid cells, sort the grid cells lexicographically.
struct RawSample {
Vec2f coord;
Vec2i cell_id;
};
std::vector<RawSample> raw_samples_sorted;
RawSample sample;
for (const Vec2f &pt : raw_samples) {
sample.coord = pt;
sample.cell_id = ((pt - corner_min) / radius).cast<int>();
raw_samples_sorted.emplace_back(sample);
}
std::sort(raw_samples_sorted.begin(), raw_samples_sorted.end(), [](const RawSample &lhs, const RawSample &rhs)
{ return lhs.cell_id.x() < rhs.cell_id.x() || (lhs.cell_id.x() == rhs.cell_id.x() && lhs.cell_id.y() < rhs.cell_id.y()); });
struct PoissonDiskGridEntry {
// Resulting output sample points for this cell:
enum {
max_positions = 4
};
Vec2f poisson_samples[max_positions];
int num_poisson_samples = 0;
// Index into raw_samples:
int first_sample_idx;
int sample_cnt;
};
struct CellIDHash {
std::size_t operator()(const Vec2i &cell_id) {
return std::hash<int>()(cell_id.x()) ^ std::hash<int>()(cell_id.y() * 593);
}
};
// Map from cell IDs to hash_data. Each hash_data points to the range in raw_samples corresponding to that cell.
// (We could just store the samples in hash_data. This implementation is an artifact of the reference paper, which
// is optimizing for GPU acceleration that we haven't implemented currently.)
typedef std::unordered_map<Vec2i, PoissonDiskGridEntry, CellIDHash> Cells;
std::unordered_map<Vec2i, PoissonDiskGridEntry, CellIDHash> cells;
{
Cells::iterator last_cell_id_it;
Vec2i last_cell_id(-1, -1);
for (int i = 0; i < raw_samples_sorted.size(); ++ i) {
const RawSample &sample = raw_samples_sorted[i];
if (sample.cell_id == last_cell_id) {
// This sample is in the same cell as the previous, so just increase the count. Cells are
// always contiguous, since we've sorted raw_samples_sorted by cell ID.
++ last_cell_id_it->second.sample_cnt;
} else {
// This is a new cell.
PoissonDiskGridEntry data;
data.first_sample_idx = i;
data.sample_cnt = 1;
auto result = cells.insert({sample.cell_id, data});
last_cell_id = sample.cell_id;
last_cell_id_it = result.first;
}
}
}
const int max_trials = 5;
const float radius_squared = radius * radius;
for (int trial = 0; trial < max_trials; ++ trial) {
// Create sample points for each entry in cells.
for (auto &it : cells) {
const Vec2i &cell_id = it.first;
PoissonDiskGridEntry &cell_data = it.second;
// This cell's raw sample points start at first_sample_idx. On trial 0, try the first one. On trial 1, try first_sample_idx + 1.
int next_sample_idx = cell_data.first_sample_idx + trial;
if (trial >= cell_data.sample_cnt)
// There are no more points to try for this cell.
continue;
const RawSample &candidate = raw_samples_sorted[next_sample_idx];
// See if this point conflicts with any other points in this cell, or with any points in
// neighboring cells. Note that it's possible to have more than one point in the same cell.
bool conflict = false;
for (int i = -1; i < 2 && ! conflict; ++ i) {
for (int j = -1; j < 2; ++ j) {
const auto &it_neighbor = cells.find(cell_id + Vec2i(i, j));
if (it_neighbor != cells.end()) {
const PoissonDiskGridEntry &neighbor = it_neighbor->second;
for (int i_sample = 0; i_sample < neighbor.num_poisson_samples; ++ i_sample)
if ((neighbor.poisson_samples[i_sample] - candidate.coord).squaredNorm() < radius_squared) {
conflict = true;
break;
}
}
}
}
if (! conflict) {
// Store the new sample.
assert(cell_data.num_poisson_samples < cell_data.max_positions);
if (cell_data.num_poisson_samples < cell_data.max_positions)
cell_data.poisson_samples[cell_data.num_poisson_samples ++] = candidate.coord;
}
}
}
// Copy the results to the output.
std::vector<Vec2f> out;
for (const auto it : cells)
for (int i = 0; i < it.second.num_poisson_samples; ++ i)
out.emplace_back(it.second.poisson_samples[i]);
return out;
}
void SLAAutoSupports::uniformly_cover(const ExPolygon& island, Structure& structure, bool is_new_island, bool just_one)
{
//int num_of_points = std::max(1, (int)((island.area()*pow(SCALING_FACTOR, 2) * m_config.tear_pressure)/m_config.support_force));
const float density_horizontal = m_config.tear_pressure / m_config.support_force;
//FIXME why?
const float poisson_radius = 1.f / (5.f * density_horizontal);
// const float poisson_radius = 1.f / (15.f * density_horizontal);
const float samples_per_mm2 = 30.f / (float(M_PI) * poisson_radius * poisson_radius);
//FIXME share the random generator. The random generator may be not so cheap to initialize, also we don't want the random generator to be restarted for each polygon.
std::random_device rd;
std::mt19937 rng(rd());
std::vector<Vec2f> raw_samples = sample_expolygon_with_boundary(island, samples_per_mm2, 5.f / poisson_radius, rng);
std::vector<Vec2f> poisson_samples = poisson_disk_from_samples(raw_samples, poisson_radius);
#ifdef SLA_AUTOSUPPORTS_DEBUG
{
static int irun = 0;
Slic3r::SVG svg(debug_out_path("SLA_supports-uniformly_cover-%d.svg", irun ++), get_extents(island));
svg.draw(island);
for (const Vec2f &pt : raw_samples)
svg.draw(Point(scale_(pt.x()), scale_(pt.y())), "red");
for (const Vec2f &pt : poisson_samples)
svg.draw(Point(scale_(pt.x()), scale_(pt.y())), "blue");
}
#endif /* NDEBUG */
assert(! poisson_samples.empty());
for (const Vec2f &pt : poisson_samples) {
m_output.emplace_back(float(pt(0)), float(pt(1)), structure.height, 0.2f, is_new_island);
structure.supports_force += m_config.support_force;
}
}
#ifdef SLA_AUTOSUPPORTS_DEBUG
void SLAAutoSupports::output_structures(const std::vector<Structure>& structures)
{
for (unsigned int i=0 ; i<structures.size(); ++i) {
std::stringstream ss;
ss << structures[i].unique_id.count() << "_" << std::setw(10) << std::setfill('0') << 1000 + (int)structures[i].height/1000 << ".png";
output_expolygons(std::vector<ExPolygon>{*structures[i].polygon}, ss.str());
}
}
void SLAAutoSupports::output_expolygons(const ExPolygons& expolys, const std::string &filename)
{
BoundingBox bb(Point(-30000000, -30000000), Point(30000000, 30000000));
Slic3r::SVG svg_cummulative(filename, bb);
for (size_t i = 0; i < expolys.size(); ++ i) {
/*Slic3r::SVG svg("single"+std::to_string(i)+".svg", bb);
svg.draw(expolys[i]);
svg.draw_outline(expolys[i].contour, "black", scale_(0.05));
svg.draw_outline(expolys[i].holes, "blue", scale_(0.05));
svg.Close();*/
svg_cummulative.draw(expolys[i]);
svg_cummulative.draw_outline(expolys[i].contour, "black", scale_(0.05));
svg_cummulative.draw_outline(expolys[i].holes, "blue", scale_(0.05));
}
}
#endif
} // namespace Slic3r
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