PrusaSlicer-NonPlainar/src/libslic3r/EdgeGrid.cpp
2021-01-29 10:46:33 +01:00

1633 lines
52 KiB
C++

#include <algorithm>
#include <vector>
#include <float.h>
#include <unordered_map>
#include <png.h>
#include "libslic3r.h"
#include "ClipperUtils.hpp"
#include "EdgeGrid.hpp"
#include "Geometry.hpp"
#include "SVG.hpp"
#include "PNGReadWrite.hpp"
// #define EDGE_GRID_DEBUG_OUTPUT
#if 0
// Enable debugging and assert in this file.
#define DEBUG
#define _DEBUG
#undef NDEBUG
#endif
#include <assert.h>
namespace Slic3r {
EdgeGrid::Grid::Grid() :
m_rows(0), m_cols(0)
{
}
EdgeGrid::Grid::~Grid()
{
m_contours.clear();
m_cell_data.clear();
m_cells.clear();
}
void EdgeGrid::Grid::create(const Polygons &polygons, coord_t resolution)
{
// Count the contours.
size_t ncontours = 0;
for (size_t j = 0; j < polygons.size(); ++ j)
if (! polygons[j].points.empty())
++ ncontours;
// Collect the contours.
m_contours.assign(ncontours, nullptr);
ncontours = 0;
for (size_t j = 0; j < polygons.size(); ++ j)
if (! polygons[j].points.empty())
m_contours[ncontours ++] = &polygons[j].points;
create_from_m_contours(resolution);
}
void EdgeGrid::Grid::create(const std::vector<const Polygon*> &polygons, coord_t resolution)
{
// Count the contours.
size_t ncontours = 0;
for (size_t j = 0; j < polygons.size(); ++ j)
if (! polygons[j]->points.empty())
++ ncontours;
// Collect the contours.
m_contours.assign(ncontours, nullptr);
ncontours = 0;
for (size_t j = 0; j < polygons.size(); ++ j)
if (! polygons[j]->points.empty())
m_contours[ncontours ++] = &polygons[j]->points;
create_from_m_contours(resolution);
}
void EdgeGrid::Grid::create(const std::vector<Points> &polygons, coord_t resolution)
{
// Count the contours.
size_t ncontours = 0;
for (size_t j = 0; j < polygons.size(); ++ j)
if (! polygons[j].empty())
++ ncontours;
// Collect the contours.
m_contours.assign(ncontours, nullptr);
ncontours = 0;
for (size_t j = 0; j < polygons.size(); ++ j)
if (! polygons[j].empty())
m_contours[ncontours ++] = &polygons[j];
create_from_m_contours(resolution);
}
void EdgeGrid::Grid::create(const ExPolygon &expoly, coord_t resolution)
{
// Count the contours.
size_t ncontours = 0;
if (! expoly.contour.points.empty())
++ ncontours;
for (size_t j = 0; j < expoly.holes.size(); ++ j)
if (! expoly.holes[j].points.empty())
++ ncontours;
// Collect the contours.
m_contours.assign(ncontours, nullptr);
ncontours = 0;
if (! expoly.contour.points.empty())
m_contours[ncontours++] = &expoly.contour.points;
for (size_t j = 0; j < expoly.holes.size(); ++ j)
if (! expoly.holes[j].points.empty())
m_contours[ncontours++] = &expoly.holes[j].points;
create_from_m_contours(resolution);
}
void EdgeGrid::Grid::create(const ExPolygons &expolygons, coord_t resolution)
{
// Count the contours.
size_t ncontours = 0;
for (size_t i = 0; i < expolygons.size(); ++ i) {
const ExPolygon &expoly = expolygons[i];
if (! expoly.contour.points.empty())
++ ncontours;
for (size_t j = 0; j < expoly.holes.size(); ++ j)
if (! expoly.holes[j].points.empty())
++ ncontours;
}
// Collect the contours.
m_contours.assign(ncontours, nullptr);
ncontours = 0;
for (size_t i = 0; i < expolygons.size(); ++ i) {
const ExPolygon &expoly = expolygons[i];
if (! expoly.contour.points.empty())
m_contours[ncontours++] = &expoly.contour.points;
for (size_t j = 0; j < expoly.holes.size(); ++ j)
if (! expoly.holes[j].points.empty())
m_contours[ncontours++] = &expoly.holes[j].points;
}
create_from_m_contours(resolution);
}
void EdgeGrid::Grid::create(const ExPolygonCollection &expolygons, coord_t resolution)
{
create(expolygons.expolygons, resolution);
}
// m_contours has been initialized. Now fill in the edge grid.
void EdgeGrid::Grid::create_from_m_contours(coord_t resolution)
{
assert(resolution > 0);
// 1) Measure the bounding box.
for (size_t i = 0; i < m_contours.size(); ++ i) {
const Slic3r::Points &pts = *m_contours[i];
for (size_t j = 0; j < pts.size(); ++ j)
m_bbox.merge(pts[j]);
}
coord_t eps = 16;
m_bbox.min(0) -= eps;
m_bbox.min(1) -= eps;
m_bbox.max(0) += eps;
m_bbox.max(1) += eps;
// 2) Initialize the edge grid.
m_resolution = resolution;
m_cols = (m_bbox.max(0) - m_bbox.min(0) + m_resolution - 1) / m_resolution;
m_rows = (m_bbox.max(1) - m_bbox.min(1) + m_resolution - 1) / m_resolution;
m_cells.assign(m_rows * m_cols, Cell());
// 3) First round of contour rasterization, count the edges per grid cell.
for (size_t i = 0; i < m_contours.size(); ++ i) {
const Slic3r::Points &pts = *m_contours[i];
for (size_t j = 0; j < pts.size(); ++ j) {
// End points of the line segment.
Slic3r::Point p1(pts[j]);
Slic3r::Point p2 = pts[(j + 1 == pts.size()) ? 0 : j + 1];
p1(0) -= m_bbox.min(0);
p1(1) -= m_bbox.min(1);
p2(0) -= m_bbox.min(0);
p2(1) -= m_bbox.min(1);
// Get the cells of the end points.
coord_t ix = p1(0) / m_resolution;
coord_t iy = p1(1) / m_resolution;
coord_t ixb = p2(0) / m_resolution;
coord_t iyb = p2(1) / m_resolution;
assert(ix >= 0 && size_t(ix) < m_cols);
assert(iy >= 0 && size_t(iy) < m_rows);
assert(ixb >= 0 && size_t(ixb) < m_cols);
assert(iyb >= 0 && size_t(iyb) < m_rows);
// Account for the end points.
++ m_cells[iy*m_cols+ix].end;
if (ix == ixb && iy == iyb)
// Both ends fall into the same cell.
continue;
// Raster the centeral part of the line.
coord_t dx = std::abs(p2(0) - p1(0));
coord_t dy = std::abs(p2(1) - p1(1));
if (p1(0) < p2(0)) {
int64_t ex = int64_t((ix + 1)*m_resolution - p1(0)) * int64_t(dy);
if (p1(1) < p2(1)) {
// x positive, y positive
int64_t ey = int64_t((iy + 1)*m_resolution - p1(1)) * int64_t(dx);
do {
assert(ix <= ixb && iy <= iyb);
if (ex < ey) {
ey -= ex;
ex = int64_t(dy) * m_resolution;
ix += 1;
}
else if (ex == ey) {
ex = int64_t(dy) * m_resolution;
ey = int64_t(dx) * m_resolution;
ix += 1;
iy += 1;
}
else {
assert(ex > ey);
ex -= ey;
ey = int64_t(dx) * m_resolution;
iy += 1;
}
++m_cells[iy*m_cols + ix].end;
} while (ix != ixb || iy != iyb);
}
else {
// x positive, y non positive
int64_t ey = int64_t(p1(1) - iy*m_resolution) * int64_t(dx);
do {
assert(ix <= ixb && iy >= iyb);
if (ex <= ey) {
ey -= ex;
ex = int64_t(dy) * m_resolution;
ix += 1;
}
else {
ex -= ey;
ey = int64_t(dx) * m_resolution;
iy -= 1;
}
++m_cells[iy*m_cols + ix].end;
} while (ix != ixb || iy != iyb);
}
}
else {
int64_t ex = int64_t(p1(0) - ix*m_resolution) * int64_t(dy);
if (p1(1) < p2(1)) {
// x non positive, y positive
int64_t ey = int64_t((iy + 1)*m_resolution - p1(1)) * int64_t(dx);
do {
assert(ix >= ixb && iy <= iyb);
if (ex < ey) {
ey -= ex;
ex = int64_t(dy) * m_resolution;
ix -= 1;
}
else {
assert(ex >= ey);
ex -= ey;
ey = int64_t(dx) * m_resolution;
iy += 1;
}
++m_cells[iy*m_cols + ix].end;
} while (ix != ixb || iy != iyb);
}
else {
// x non positive, y non positive
int64_t ey = int64_t(p1(1) - iy*m_resolution) * int64_t(dx);
do {
assert(ix >= ixb && iy >= iyb);
if (ex < ey) {
ey -= ex;
ex = int64_t(dy) * m_resolution;
ix -= 1;
}
else if (ex == ey) {
// The lower edge of a grid cell belongs to the cell.
// Handle the case where the ray may cross the lower left corner of a cell in a general case,
// or a left or lower edge in a degenerate case (horizontal or vertical line).
if (dx > 0) {
ex = int64_t(dy) * m_resolution;
ix -= 1;
}
if (dy > 0) {
ey = int64_t(dx) * m_resolution;
iy -= 1;
}
}
else {
assert(ex > ey);
ex -= ey;
ey = int64_t(dx) * m_resolution;
iy -= 1;
}
++m_cells[iy*m_cols + ix].end;
} while (ix != ixb || iy != iyb);
}
}
}
}
// 4) Prefix sum the numbers of hits per cells to get an index into m_cell_data.
size_t cnt = m_cells.front().end;
for (size_t i = 1; i < m_cells.size(); ++ i) {
m_cells[i].begin = cnt;
cnt += m_cells[i].end;
m_cells[i].end = cnt;
}
// 5) Allocate the cell data.
m_cell_data.assign(cnt, std::pair<size_t, size_t>(size_t(-1), size_t(-1)));
// 6) Finally fill in m_cell_data by rasterizing the lines once again.
for (size_t i = 0; i < m_cells.size(); ++i)
m_cells[i].end = m_cells[i].begin;
struct Visitor {
Visitor(std::vector<std::pair<size_t, size_t>> &cell_data, std::vector<Cell> &cells, size_t cols) :
cell_data(cell_data), cells(cells), cols(cols), i(0), j(0) {}
inline bool operator()(coord_t iy, coord_t ix) {
cell_data[cells[iy*cols + ix].end++] = std::pair<size_t, size_t>(i, j);
// Continue traversing the grid along the edge.
return true;
}
std::vector<std::pair<size_t, size_t>> &cell_data;
std::vector<Cell> &cells;
size_t cols;
size_t i;
size_t j;
} visitor(m_cell_data, m_cells, m_cols);
assert(visitor.i == 0);
for (; visitor.i < m_contours.size(); ++ visitor.i) {
const Slic3r::Points &pts = *m_contours[visitor.i];
for (visitor.j = 0; visitor.j < pts.size(); ++ visitor.j)
this->visit_cells_intersecting_line(pts[visitor.j], pts[(visitor.j + 1 == pts.size()) ? 0 : visitor.j + 1], visitor);
}
}
#if 0
// Divide, round to a grid coordinate.
// Divide x/y, round down. y is expected to be positive.
static inline coord_t div_floor(coord_t x, coord_t y)
{
assert(y > 0);
return ((x < 0) ? (x - y + 1) : x) / y;
}
// Walk the polyline, test whether any lines of this polyline does not intersect
// any line stored into the grid.
bool EdgeGrid::Grid::intersect(const MultiPoint &polyline, bool closed)
{
size_t n = polyline.points.size();
if (closed)
++ n;
for (size_t i = 0; i < n; ++ i) {
size_t j = i + 1;
if (j == polyline.points.size())
j = 0;
Point p1src = polyline.points[i];
Point p2src = polyline.points[j];
Point p1 = p1src;
Point p2 = p2src;
// Discretize the line segment p1, p2.
p1(0) -= m_bbox.min(0);
p1(1) -= m_bbox.min(1);
p2(0) -= m_bbox.min(0);
p2(1) -= m_bbox.min(1);
// Get the cells of the end points.
coord_t ix = div_floor(p1(0), m_resolution);
coord_t iy = div_floor(p1(1), m_resolution);
coord_t ixb = div_floor(p2(0), m_resolution);
coord_t iyb = div_floor(p2(1), m_resolution);
// assert(ix >= 0 && ix < m_cols);
// assert(iy >= 0 && iy < m_rows);
// assert(ixb >= 0 && ixb < m_cols);
// assert(iyb >= 0 && iyb < m_rows);
// Account for the end points.
if (line_cell_intersect(p1src, p2src, m_cells[iy*m_cols + ix]))
return true;
if (ix == ixb && iy == iyb)
// Both ends fall into the same cell.
continue;
// Raster the centeral part of the line.
coord_t dx = std::abs(p2(0) - p1(0));
coord_t dy = std::abs(p2(1) - p1(1));
if (p1(0) < p2(0)) {
int64_t ex = int64_t((ix + 1)*m_resolution - p1(0)) * int64_t(dy);
if (p1(1) < p2(1)) {
int64_t ey = int64_t((iy + 1)*m_resolution - p1(1)) * int64_t(dx);
do {
assert(ix <= ixb && iy <= iyb);
if (ex < ey) {
ey -= ex;
ex = int64_t(dy) * m_resolution;
ix += 1;
}
else if (ex == ey) {
ex = int64_t(dy) * m_resolution;
ey = int64_t(dx) * m_resolution;
ix += 1;
iy += 1;
}
else {
assert(ex > ey);
ex -= ey;
ey = int64_t(dx) * m_resolution;
iy += 1;
}
if (line_cell_intersect(p1src, p2src, m_cells[iy*m_cols + ix]))
return true;
} while (ix != ixb || iy != iyb);
}
else {
int64_t ey = int64_t(p1(1) - iy*m_resolution) * int64_t(dx);
do {
assert(ix <= ixb && iy >= iyb);
if (ex <= ey) {
ey -= ex;
ex = int64_t(dy) * m_resolution;
ix += 1;
}
else {
ex -= ey;
ey = int64_t(dx) * m_resolution;
iy -= 1;
}
if (line_cell_intersect(p1src, p2src, m_cells[iy*m_cols + ix]))
return true;
} while (ix != ixb || iy != iyb);
}
}
else {
int64_t ex = int64_t(p1(0) - ix*m_resolution) * int64_t(dy);
if (p1(1) < p2(1)) {
int64_t ey = int64_t((iy + 1)*m_resolution - p1(1)) * int64_t(dx);
do {
assert(ix >= ixb && iy <= iyb);
if (ex < ey) {
ey -= ex;
ex = int64_t(dy) * m_resolution;
ix -= 1;
}
else {
assert(ex >= ey);
ex -= ey;
ey = int64_t(dx) * m_resolution;
iy += 1;
}
if (line_cell_intersect(p1src, p2src, m_cells[iy*m_cols + ix]))
return true;
} while (ix != ixb || iy != iyb);
}
else {
int64_t ey = int64_t(p1(1) - iy*m_resolution) * int64_t(dx);
do {
assert(ix >= ixb && iy >= iyb);
if (ex < ey) {
ey -= ex;
ex = int64_t(dy) * m_resolution;
ix -= 1;
}
else if (ex == ey) {
if (dx > 0) {
ex = int64_t(dy) * m_resolution;
ix -= 1;
}
if (dy > 0) {
ey = int64_t(dx) * m_resolution;
iy -= 1;
}
}
else {
assert(ex > ey);
ex -= ey;
ey = int64_t(dx) * m_resolution;
iy -= 1;
}
if (line_cell_intersect(p1src, p2src, m_cells[iy*m_cols + ix]))
return true;
} while (ix != ixb || iy != iyb);
}
}
}
return false;
}
bool EdgeGrid::Grid::line_cell_intersect(const Point &p1a, const Point &p2a, const Cell &cell)
{
BoundingBox bbox(p1a, p1a);
bbox.merge(p2a);
int64_t va_x = p2a(0) - p1a(0);
int64_t va_y = p2a(1) - p1a(1);
for (size_t i = cell.begin; i != cell.end; ++ i) {
const std::pair<size_t, size_t> &cell_data = m_cell_data[i];
// Contour indexed by the ith line of this cell.
const Slic3r::Points &contour = *m_contours[cell_data.first];
// Point indices in contour indexed by the ith line of this cell.
size_t idx1 = cell_data.second;
size_t idx2 = idx1 + 1;
if (idx2 == contour.size())
idx2 = 0;
// The points of the ith line of this cell and its bounding box.
const Point &p1b = contour[idx1];
const Point &p2b = contour[idx2];
BoundingBox bbox2(p1b, p1b);
bbox2.merge(p2b);
// Do the bounding boxes intersect?
if (! bbox.overlap(bbox2))
continue;
// Now intersect the two line segments using exact arithmetics.
int64_t w1_x = p1b(0) - p1a(0);
int64_t w1_y = p1b(1) - p1a(1);
int64_t w2_x = p2b(0) - p1a(0);
int64_t w2_y = p2b(1) - p1a(1);
int64_t side1 = va_x * w1_y - va_y * w1_x;
int64_t side2 = va_x * w2_y - va_y * w2_x;
if (side1 == side2 && side1 != 0)
// The line segments don't intersect.
continue;
w1_x = p1a(0) - p1b(0);
w1_y = p1a(1) - p1b(1);
w2_x = p2a(0) - p1b(0);
w2_y = p2a(1) - p1b(1);
int64_t vb_x = p2b(0) - p1b(0);
int64_t vb_y = p2b(1) - p1b(1);
side1 = vb_x * w1_y - vb_y * w1_x;
side2 = vb_x * w2_y - vb_y * w2_x;
if (side1 == side2 && side1 != 0)
// The line segments don't intersect.
continue;
// The line segments intersect.
return true;
}
// The line segment (p1a, p2a) does not intersect any of the line segments inside this cell.
return false;
}
// Test, whether a point is inside a contour.
bool EdgeGrid::Grid::inside(const Point &pt_src)
{
Point p = pt_src;
p(0) -= m_bbox.min(0);
p(1) -= m_bbox.min(1);
// Get the cell of the point.
if (p(0) < 0 || p(1) < 0)
return false;
coord_t ix = p(0) / m_resolution;
coord_t iy = p(1) / m_resolution;
if (ix >= this->m_cols || iy >= this->m_rows)
return false;
size_t i_closest = (size_t)-1;
bool inside = false;
{
// Hit in the first cell?
const Cell &cell = m_cells[iy * m_cols + ix];
for (size_t i = cell.begin; i != cell.end; ++ i) {
const std::pair<size_t, size_t> &cell_data = m_cell_data[i];
// Contour indexed by the ith line of this cell.
const Slic3r::Points &contour = *m_contours[cell_data.first];
// Point indices in contour indexed by the ith line of this cell.
size_t idx1 = cell_data.second;
size_t idx2 = idx1 + 1;
if (idx2 == contour.size())
idx2 = 0;
const Point &p1 = contour[idx1];
const Point &p2 = contour[idx2];
if (p1(1) < p2(1)) {
if (p(1) < p1(1) || p(1) > p2(1))
continue;
//FIXME finish this!
int64_t vx = 0;// pt_src
//FIXME finish this!
int64_t det = 0;
} else if (p1(1) != p2(1)) {
assert(p1(1) > p2(1));
if (p(1) < p2(1) || p(1) > p1(1))
continue;
} else {
assert(p1(1) == p2(1));
if (p1(1) == p(1)) {
if (p(0) >= p1(0) && p(0) <= p2(0))
// On the segment.
return true;
// Before or after the segment.
size_t idx0 = idx1 - 1;
size_t idx2 = idx1 + 1;
if (idx0 == (size_t)-1)
idx0 = contour.size() - 1;
if (idx2 == contour.size())
idx2 = 0;
}
}
}
}
//FIXME This code follows only a single direction. Better to follow the direction closest to the bounding box.
}
#endif
template<const int INCX, const int INCY>
struct PropagateDanielssonSingleStep {
PropagateDanielssonSingleStep(float *aL, unsigned char *asigns, size_t astride, coord_t aresolution) :
L(aL), signs(asigns), stride(astride), resolution(aresolution) {}
inline void operator()(int r, int c, int addr_delta) {
size_t addr = r * stride + c;
if ((signs[addr] & 2) == 0) {
float *v = &L[addr << 1];
float l = v[0] * v[0] + v[1] * v[1];
float *v2s = v + (addr_delta << 1);
float v2[2] = {
v2s[0] + INCX * resolution,
v2s[1] + INCY * resolution
};
float l2 = v2[0] * v2[0] + v2[1] * v2[1];
if (l2 < l) {
v[0] = v2[0];
v[1] = v2[1];
}
}
}
float *L;
unsigned char *signs;
size_t stride;
coord_t resolution;
};
struct PropagateDanielssonSingleVStep3 {
PropagateDanielssonSingleVStep3(float *aL, unsigned char *asigns, size_t astride, coord_t aresolution) :
L(aL), signs(asigns), stride(astride), resolution(aresolution) {}
inline void operator()(int r, int c, int addr_delta, bool has_l, bool has_r) {
size_t addr = r * stride + c;
if ((signs[addr] & 2) == 0) {
float *v = &L[addr<<1];
float l = v[0]*v[0]+v[1]*v[1];
float *v2s = v+(addr_delta<<1);
float v2[2] = {
v2s[0],
v2s[1] + resolution
};
float l2 = v2[0]*v2[0]+v2[1]*v2[1];
if (l2 < l) {
v[0] = v2[0];
v[1] = v2[1];
}
if (has_l) {
float *v2sl = v2s - 1;
v2[0] = v2sl[0] + resolution;
v2[1] = v2sl[1] + resolution;
l2 = v2[0]*v2[0]+v2[1]*v2[1];
if (l2 < l) {
v[0] = v2[0];
v[1] = v2[1];
}
}
if (has_r) {
float *v2sr = v2s + 1;
v2[0] = v2sr[0] + resolution;
v2[1] = v2sr[1] + resolution;
l2 = v2[0]*v2[0]+v2[1]*v2[1];
if (l2 < l) {
v[0] = v2[0];
v[1] = v2[1];
}
}
}
}
float *L;
unsigned char *signs;
size_t stride;
coord_t resolution;
};
void EdgeGrid::Grid::calculate_sdf()
{
#ifdef EDGE_GRID_DEBUG_OUTPUT
static int iRun = 0;
++ iRun;
#endif
// 1) Initialize a signum and an unsigned vector to a zero iso surface.
size_t nrows = m_rows + 1;
size_t ncols = m_cols + 1;
// Unsigned vectors towards the closest point on the surface.
std::vector<float> L(nrows * ncols * 2, FLT_MAX);
// Bit 0 set - negative.
// Bit 1 set - original value, the distance value shall not be changed by the Danielsson propagation.
// Bit 2 set - signum not propagated yet.
std::vector<unsigned char> signs(nrows * ncols, 4);
// SDF will be initially filled with unsigned DF.
// m_signed_distance_field.assign(nrows * ncols, FLT_MAX);
float search_radius = float(m_resolution<<1);
m_signed_distance_field.assign(nrows * ncols, search_radius);
// For each cell:
for (int r = 0; r < (int)m_rows; ++ r) {
for (int c = 0; c < (int)m_cols; ++ c) {
const Cell &cell = m_cells[r * m_cols + c];
// For each segment in the cell:
for (size_t i = cell.begin; i != cell.end; ++ i) {
const Slic3r::Points &pts = *m_contours[m_cell_data[i].first];
size_t ipt = m_cell_data[i].second;
// End points of the line segment.
const Slic3r::Point &p1 = pts[ipt];
const Slic3r::Point &p2 = pts[(ipt + 1 == pts.size()) ? 0 : ipt + 1];
// Segment vector
const Slic3r::Point v_seg = p2 - p1;
// l2 of v_seg
const int64_t l2_seg = int64_t(v_seg(0)) * int64_t(v_seg(0)) + int64_t(v_seg(1)) * int64_t(v_seg(1));
// For each corner of this cell and its 1 ring neighbours:
for (int corner_y = -1; corner_y < 3; ++ corner_y) {
coord_t corner_r = r + corner_y;
if (corner_r < 0 || (size_t)corner_r >= nrows)
continue;
for (int corner_x = -1; corner_x < 3; ++ corner_x) {
coord_t corner_c = c + corner_x;
if (corner_c < 0 || (size_t)corner_c >= ncols)
continue;
float &d_min = m_signed_distance_field[corner_r * ncols + corner_c];
Slic3r::Point pt(m_bbox.min(0) + corner_c * m_resolution, m_bbox.min(1) + corner_r * m_resolution);
Slic3r::Point v_pt = pt - p1;
// dot(p2-p1, pt-p1)
int64_t t_pt = int64_t(v_seg(0)) * int64_t(v_pt(0)) + int64_t(v_seg(1)) * int64_t(v_pt(1));
if (t_pt < 0) {
// Closest to p1.
double dabs = sqrt(int64_t(v_pt(0)) * int64_t(v_pt(0)) + int64_t(v_pt(1)) * int64_t(v_pt(1)));
if (dabs < d_min) {
// Previous point.
const Slic3r::Point &p0 = pts[(ipt == 0) ? (pts.size() - 1) : ipt - 1];
Slic3r::Point v_seg_prev = p1 - p0;
int64_t t2_pt = int64_t(v_seg_prev(0)) * int64_t(v_pt(0)) + int64_t(v_seg_prev(1)) * int64_t(v_pt(1));
if (t2_pt > 0) {
// Inside the wedge between the previous and the next segment.
// Set the signum depending on whether the vertex is convex or reflex.
int64_t det = int64_t(v_seg_prev(0)) * int64_t(v_seg(1)) - int64_t(v_seg_prev(1)) * int64_t(v_seg(0));
assert(det != 0);
d_min = dabs;
// Fill in an unsigned vector towards the zero iso surface.
float *l = &L[(corner_r * ncols + corner_c) << 1];
l[0] = std::abs(v_pt(0));
l[1] = std::abs(v_pt(1));
#ifdef _DEBUG
double dabs2 = sqrt(l[0]*l[0]+l[1]*l[1]);
assert(std::abs(dabs-dabs2) < 1e-4 * std::max(dabs, dabs2));
#endif /* _DEBUG */
signs[corner_r * ncols + corner_c] = ((det < 0) ? 1 : 0) | 2;
}
}
}
else if (t_pt > l2_seg) {
// Closest to p2. Then p2 is the starting point of another segment, which shall be discovered in the same cell.
continue;
} else {
// Closest to the segment.
assert(t_pt >= 0 && t_pt <= l2_seg);
int64_t d_seg = int64_t(v_seg(1)) * int64_t(v_pt(0)) - int64_t(v_seg(0)) * int64_t(v_pt(1));
double d = double(d_seg) / sqrt(double(l2_seg));
double dabs = std::abs(d);
if (dabs < d_min) {
d_min = dabs;
// Fill in an unsigned vector towards the zero iso surface.
float *l = &L[(corner_r * ncols + corner_c) << 1];
float linv = float(d_seg) / float(l2_seg);
l[0] = std::abs(float(v_seg(1)) * linv);
l[1] = std::abs(float(v_seg(0)) * linv);
#ifdef _DEBUG
double dabs2 = sqrt(l[0]*l[0]+l[1]*l[1]);
assert(std::abs(dabs-dabs2) <= 1e-4 * std::max(dabs, dabs2));
#endif /* _DEBUG */
signs[corner_r * ncols + corner_c] = ((d_seg < 0) ? 1 : 0) | 2;
}
}
}
}
}
}
}
#ifdef EDGE_GRID_DEBUG_OUTPUT
{
std::vector<uint8_t> pixels(ncols * nrows * 3, 0);
for (coord_t r = 0; r < nrows; ++ r) {
for (coord_t c = 0; c < ncols; ++ c) {
uint8_t *pxl = pixels.data() + (((nrows - r - 1) * ncols) + c) * 3;
float d = m_signed_distance_field[r * ncols + c];
if (d != search_radius) {
float s = 255 * d / search_radius;
int is = std::max(0, std::min(255, int(floor(s + 0.5f))));
pxl[0] = 255;
pxl[1] = 255 - is;
pxl[2] = 255 - is;
}
else {
pxl[0] = 0;
pxl[1] = 255;
pxl[2] = 0;
}
}
}
png::write_rgb_to_file_scaled(debug_out_path("unsigned_df-%d.png", iRun), ncols, nrows, pixels, 10);
}
{
std::vector<uint8_t> pixels(ncols * nrows * 3, 0);
for (coord_t r = 0; r < nrows; ++ r) {
for (coord_t c = 0; c < ncols; ++ c) {
unsigned char *pxl = pixels.data() + (((nrows - r - 1) * ncols) + c) * 3;
float d = m_signed_distance_field[r * ncols + c];
if (d != search_radius) {
float s = 255 * d / search_radius;
int is = std::max(0, std::min(255, int(floor(s + 0.5f))));
if ((signs[r * ncols + c] & 1) == 0) {
// Positive
pxl[0] = 255;
pxl[1] = 255 - is;
pxl[2] = 255 - is;
}
else {
// Negative
pxl[0] = 255 - is;
pxl[1] = 255 - is;
pxl[2] = 255;
}
}
else {
pxl[0] = 0;
pxl[1] = 255;
pxl[2] = 0;
}
}
}
png::write_rgb_to_file_scaled(debug_out_path("signed_df-%d.png", iRun), ncols, nrows, pixels, 10);
}
#endif // EDGE_GRID_DEBUG_OUTPUT
// 2) Propagate the signum.
#define PROPAGATE_SIGNUM_SINGLE_STEP(DELTA) do { \
size_t addr = r * ncols + c; \
unsigned char &cur_val = signs[addr]; \
if (cur_val & 4) { \
unsigned char old_val = signs[addr + (DELTA)]; \
if ((old_val & 4) == 0) \
cur_val = old_val & 1; \
} \
} while (0);
// Top to bottom propagation.
for (size_t r = 0; r < nrows; ++ r) {
if (r > 0)
for (size_t c = 0; c < ncols; ++ c)
PROPAGATE_SIGNUM_SINGLE_STEP(- int(ncols));
for (size_t c = 1; c < ncols; ++ c)
PROPAGATE_SIGNUM_SINGLE_STEP(- 1);
for (int c = int(ncols) - 2; c >= 0; -- c)
PROPAGATE_SIGNUM_SINGLE_STEP(+ 1);
}
// Bottom to top propagation.
for (int r = int(nrows) - 2; r >= 0; -- r) {
for (size_t c = 0; c < ncols; ++ c)
PROPAGATE_SIGNUM_SINGLE_STEP(+ ncols);
for (size_t c = 1; c < ncols; ++ c)
PROPAGATE_SIGNUM_SINGLE_STEP(- 1);
for (int c = int(ncols) - 2; c >= 0; -- c)
PROPAGATE_SIGNUM_SINGLE_STEP(+ 1);
}
#undef PROPAGATE_SIGNUM_SINGLE_STEP
// 3) Propagate the distance by the Danielsson chamfer metric.
// Top to bottom propagation.
PropagateDanielssonSingleStep<1, 0> danielsson_hstep(L.data(), signs.data(), ncols, m_resolution);
PropagateDanielssonSingleStep<0, 1> danielsson_vstep(L.data(), signs.data(), ncols, m_resolution);
PropagateDanielssonSingleVStep3 danielsson_vstep3(L.data(), signs.data(), ncols, m_resolution);
// Top to bottom propagation.
for (size_t r = 0; r < nrows; ++ r) {
if (r > 0)
for (size_t c = 0; c < ncols; ++ c)
danielsson_vstep(r, c, -int(ncols));
// PROPAGATE_DANIELSSON_SINGLE_VSTEP3(-int(ncols), c != 0, c + 1 != ncols);
for (size_t c = 1; c < ncols; ++ c)
danielsson_hstep(r, c, -1);
for (int c = int(ncols) - 2; c >= 0; -- c)
danielsson_hstep(r, c, +1);
}
// Bottom to top propagation.
for (int r = int(nrows) - 2; r >= 0; -- r) {
for (size_t c = 0; c < ncols; ++ c)
danielsson_vstep(r, c, +ncols);
// PROPAGATE_DANIELSSON_SINGLE_VSTEP3(+int(ncols), c != 0, c + 1 != ncols);
for (size_t c = 1; c < ncols; ++ c)
danielsson_hstep(r, c, -1);
for (int c = int(ncols) - 2; c >= 0; -- c)
danielsson_hstep(r, c, +1);
}
// Update signed distance field from absolte vectors to the iso-surface.
for (size_t r = 0; r < nrows; ++ r) {
for (size_t c = 0; c < ncols; ++ c) {
size_t addr = r * ncols + c;
float *v = &L[addr<<1];
float d = sqrt(v[0]*v[0]+v[1]*v[1]);
if (signs[addr] & 1)
d = -d;
m_signed_distance_field[addr] = d;
}
}
#ifdef EDGE_GRID_DEBUG_OUTPUT
{
std::vector<uint8_t> pixels(ncols * nrows * 3, 0);
float search_radius = float(m_resolution * 5);
for (coord_t r = 0; r < nrows; ++r) {
for (coord_t c = 0; c < ncols; ++c) {
uint8_t *pxl = pixels.data() + (((nrows - r - 1) * ncols) + c) * 3;
uint8_t sign = signs[r * ncols + c];
switch (sign) {
case 0:
// Positive, outside of a narrow band.
pxl[0] = 0;
pxl[1] = 0;
pxl[2] = 255;
break;
case 1:
// Negative, outside of a narrow band.
pxl[0] = 255;
pxl[1] = 0;
pxl[2] = 0;
break;
case 2:
// Positive, outside of a narrow band.
pxl[0] = 100;
pxl[1] = 100;
pxl[2] = 255;
break;
case 3:
// Negative, outside of a narrow band.
pxl[0] = 255;
pxl[1] = 100;
pxl[2] = 100;
break;
case 4:
// This shall not happen. Undefined signum.
pxl[0] = 0;
pxl[1] = 255;
pxl[2] = 0;
break;
default:
// This shall not happen. Invalid signum value.
pxl[0] = 255;
pxl[1] = 255;
pxl[2] = 255;
break;
}
}
}
png::write_rgb_to_file_scaled(debug_out_path("signed_df-signs-%d.png", iRun), ncols, nrows, pixels, 10);
}
#endif // EDGE_GRID_DEBUG_OUTPUT
#ifdef EDGE_GRID_DEBUG_OUTPUT
{
std::vector<uint8_t> pixels(ncols * nrows * 3, 0);
float search_radius = float(m_resolution * 5);
for (coord_t r = 0; r < nrows; ++r) {
for (coord_t c = 0; c < ncols; ++c) {
uint8_t *pxl = pixels.data() + (((nrows - r - 1) * ncols) + c) * 3;
float d = m_signed_distance_field[r * ncols + c];
float s = 255.f * fabs(d) / search_radius;
int is = std::max(0, std::min(255, int(floor(s + 0.5f))));
if (d < 0.f) {
pxl[0] = 255;
pxl[1] = 255 - is;
pxl[2] = 255 - is;
}
else {
pxl[0] = 255 - is;
pxl[1] = 255 - is;
pxl[2] = 255;
}
}
}
png::write_rgb_to_file_scaled(debug_out_path("signed_df2-%d.png", iRun), ncols, nrows, pixels, 10);
}
#endif // EDGE_GRID_DEBUG_OUTPUT
}
float EdgeGrid::Grid::signed_distance_bilinear(const Point &pt) const
{
coord_t x = pt(0) - m_bbox.min(0);
coord_t y = pt(1) - m_bbox.min(1);
coord_t w = m_resolution * m_cols;
coord_t h = m_resolution * m_rows;
bool clamped = false;
coord_t xcl = x;
coord_t ycl = y;
if (x < 0) {
xcl = 0;
clamped = true;
} else if (x >= w) {
xcl = w - 1;
clamped = true;
}
if (y < 0) {
ycl = 0;
clamped = true;
} else if (y >= h) {
ycl = h - 1;
clamped = true;
}
coord_t cell_c = coord_t(floor(xcl / m_resolution));
coord_t cell_r = coord_t(floor(ycl / m_resolution));
float tx = float(xcl - cell_c * m_resolution) / float(m_resolution);
assert(tx >= -1e-5 && tx < 1.f + 1e-5);
float ty = float(ycl - cell_r * m_resolution) / float(m_resolution);
assert(ty >= -1e-5 && ty < 1.f + 1e-5);
size_t addr = cell_r * (m_cols + 1) + cell_c;
float f00 = m_signed_distance_field[addr];
float f01 = m_signed_distance_field[addr+1];
addr += m_cols + 1;
float f10 = m_signed_distance_field[addr];
float f11 = m_signed_distance_field[addr+1];
float f0 = (1.f - tx) * f00 + tx * f01;
float f1 = (1.f - tx) * f10 + tx * f11;
float f = (1.f - ty) * f0 + ty * f1;
if (clamped) {
if (f > 0) {
if (x < 0)
f += -x;
else if (x >= w)
f += x - w + 1;
if (y < 0)
f += -y;
else if (y >= h)
f += y - h + 1;
} else {
if (x < 0)
f -= -x;
else if (x >= w)
f -= x - w + 1;
if (y < 0)
f -= -y;
else if (y >= h)
f -= y - h + 1;
}
}
return f;
}
EdgeGrid::Grid::ClosestPointResult EdgeGrid::Grid::closest_point(const Point &pt, coord_t search_radius) const
{
BoundingBox bbox;
bbox.min = bbox.max = Point(pt(0) - m_bbox.min(0), pt(1) - m_bbox.min(1));
bbox.defined = true;
// Upper boundary, round to grid and test validity.
bbox.max(0) += search_radius;
bbox.max(1) += search_radius;
ClosestPointResult result;
if (bbox.max(0) < 0 || bbox.max(1) < 0)
return result;
bbox.max(0) /= m_resolution;
bbox.max(1) /= m_resolution;
if ((size_t)bbox.max(0) >= m_cols)
bbox.max(0) = m_cols - 1;
if ((size_t)bbox.max(1) >= m_rows)
bbox.max(1) = m_rows - 1;
// Lower boundary, round to grid and test validity.
bbox.min(0) -= search_radius;
bbox.min(1) -= search_radius;
if (bbox.min(0) < 0)
bbox.min(0) = 0;
if (bbox.min(1) < 0)
bbox.min(1) = 0;
bbox.min(0) /= m_resolution;
bbox.min(1) /= m_resolution;
// Is the interval empty?
if (bbox.min(0) > bbox.max(0) ||
bbox.min(1) > bbox.max(1))
return result;
// Traverse all cells in the bounding box.
double d_min = double(search_radius);
// Signum of the distance field at pt.
int sign_min = 0;
double l2_seg_min = 1.;
for (int r = bbox.min(1); r <= bbox.max(1); ++ r) {
for (int c = bbox.min(0); c <= bbox.max(0); ++ c) {
const Cell &cell = m_cells[r * m_cols + c];
for (size_t i = cell.begin; i < cell.end; ++ i) {
const size_t contour_idx = m_cell_data[i].first;
const Slic3r::Points &pts = *m_contours[contour_idx];
size_t ipt = m_cell_data[i].second;
// End points of the line segment.
const Slic3r::Point &p1 = pts[ipt];
const Slic3r::Point &p2 = pts[(ipt + 1 == pts.size()) ? 0 : ipt + 1];
const Slic3r::Point v_seg = p2 - p1;
const Slic3r::Point v_pt = pt - p1;
// dot(p2-p1, pt-p1)
int64_t t_pt = int64_t(v_seg(0)) * int64_t(v_pt(0)) + int64_t(v_seg(1)) * int64_t(v_pt(1));
// l2 of seg
int64_t l2_seg = int64_t(v_seg(0)) * int64_t(v_seg(0)) + int64_t(v_seg(1)) * int64_t(v_seg(1));
if (t_pt < 0) {
// Closest to p1.
double dabs = sqrt(int64_t(v_pt(0)) * int64_t(v_pt(0)) + int64_t(v_pt(1)) * int64_t(v_pt(1)));
if (dabs < d_min) {
// Previous point.
const Slic3r::Point &p0 = pts[(ipt == 0) ? (pts.size() - 1) : ipt - 1];
Slic3r::Point v_seg_prev = p1 - p0;
int64_t t2_pt = int64_t(v_seg_prev(0)) * int64_t(v_pt(0)) + int64_t(v_seg_prev(1)) * int64_t(v_pt(1));
if (t2_pt > 0) {
// Inside the wedge between the previous and the next segment.
d_min = dabs;
// Set the signum depending on whether the vertex is convex or reflex.
int64_t det = int64_t(v_seg_prev(0)) * int64_t(v_seg(1)) - int64_t(v_seg_prev(1)) * int64_t(v_seg(0));
assert(det != 0);
sign_min = (det > 0) ? 1 : -1;
result.contour_idx = contour_idx;
result.start_point_idx = ipt;
result.t = 0.;
#ifndef NDEBUG
Vec2d vfoot = (p1 - pt).cast<double>();
double dist_foot = vfoot.norm();
double dist_foot_err = dist_foot - d_min;
assert(std::abs(dist_foot_err) < 1e-7 * d_min);
#endif /* NDEBUG */
}
}
}
else if (t_pt > l2_seg) {
// Closest to p2. Then p2 is the starting point of another segment, which shall be discovered in the same cell.
continue;
} else {
// Closest to the segment.
assert(t_pt >= 0 && t_pt <= l2_seg);
int64_t d_seg = int64_t(v_seg(1)) * int64_t(v_pt(0)) - int64_t(v_seg(0)) * int64_t(v_pt(1));
double d = double(d_seg) / sqrt(double(l2_seg));
double dabs = std::abs(d);
if (dabs < d_min) {
d_min = dabs;
sign_min = (d_seg < 0) ? -1 : ((d_seg == 0) ? 0 : 1);
l2_seg_min = l2_seg;
result.contour_idx = contour_idx;
result.start_point_idx = ipt;
result.t = t_pt;
#ifndef NDEBUG
Vec2d foot = p1.cast<double>() * (1. - result.t / l2_seg_min) + p2.cast<double>() * (result.t / l2_seg_min);
Vec2d vfoot = foot - pt.cast<double>();
double dist_foot = vfoot.norm();
double dist_foot_err = dist_foot - d_min;
assert(std::abs(dist_foot_err) < 1e-7 || std::abs(dist_foot_err) < 1e-7 * d_min);
#endif /* NDEBUG */
}
}
}
}
}
if (result.contour_idx != size_t(-1) && d_min <= double(search_radius)) {
result.distance = d_min * sign_min;
result.t /= l2_seg_min;
assert(result.t >= 0. && result.t <= 1.);
#ifndef NDEBUG
{
const Slic3r::Points &pts = *m_contours[result.contour_idx];
const Slic3r::Point &p1 = pts[result.start_point_idx];
const Slic3r::Point &p2 = pts[(result.start_point_idx + 1 == pts.size()) ? 0 : result.start_point_idx + 1];
Vec2d vfoot;
if (result.t == 0)
vfoot = p1.cast<double>() - pt.cast<double>();
else
vfoot = p1.cast<double>() * (1. - result.t) + p2.cast<double>() * result.t - pt.cast<double>();
double dist_foot = vfoot.norm();
double dist_foot_err = dist_foot - std::abs(result.distance);
assert(std::abs(dist_foot_err) < 1e-7 || std::abs(dist_foot_err) < 1e-7 * std::abs(result.distance));
}
#endif /* NDEBUG */
} else
result = ClosestPointResult();
return result;
}
bool EdgeGrid::Grid::signed_distance_edges(const Point &pt, coord_t search_radius, coordf_t &result_min_dist, bool *pon_segment) const
{
BoundingBox bbox;
bbox.min = bbox.max = Point(pt(0) - m_bbox.min(0), pt(1) - m_bbox.min(1));
bbox.defined = true;
// Upper boundary, round to grid and test validity.
bbox.max(0) += search_radius;
bbox.max(1) += search_radius;
if (bbox.max(0) < 0 || bbox.max(1) < 0)
return false;
bbox.max(0) /= m_resolution;
bbox.max(1) /= m_resolution;
if ((size_t)bbox.max(0) >= m_cols)
bbox.max(0) = m_cols - 1;
if ((size_t)bbox.max(1) >= m_rows)
bbox.max(1) = m_rows - 1;
// Lower boundary, round to grid and test validity.
bbox.min(0) -= search_radius;
bbox.min(1) -= search_radius;
if (bbox.min(0) < 0)
bbox.min(0) = 0;
if (bbox.min(1) < 0)
bbox.min(1) = 0;
bbox.min(0) /= m_resolution;
bbox.min(1) /= m_resolution;
// Is the interval empty?
if (bbox.min(0) > bbox.max(0) ||
bbox.min(1) > bbox.max(1))
return false;
// Traverse all cells in the bounding box.
double d_min = double(search_radius);
// Signum of the distance field at pt.
int sign_min = 0;
bool on_segment = false;
for (int r = bbox.min(1); r <= bbox.max(1); ++ r) {
for (int c = bbox.min(0); c <= bbox.max(0); ++ c) {
const Cell &cell = m_cells[r * m_cols + c];
for (size_t i = cell.begin; i < cell.end; ++ i) {
const Slic3r::Points &pts = *m_contours[m_cell_data[i].first];
size_t ipt = m_cell_data[i].second;
// End points of the line segment.
const Slic3r::Point &p1 = pts[ipt];
const Slic3r::Point &p2 = pts[(ipt + 1 == pts.size()) ? 0 : ipt + 1];
Slic3r::Point v_seg = p2 - p1;
Slic3r::Point v_pt = pt - p1;
// dot(p2-p1, pt-p1)
int64_t t_pt = int64_t(v_seg(0)) * int64_t(v_pt(0)) + int64_t(v_seg(1)) * int64_t(v_pt(1));
// l2 of seg
int64_t l2_seg = int64_t(v_seg(0)) * int64_t(v_seg(0)) + int64_t(v_seg(1)) * int64_t(v_seg(1));
if (t_pt < 0) {
// Closest to p1.
double dabs = sqrt(int64_t(v_pt(0)) * int64_t(v_pt(0)) + int64_t(v_pt(1)) * int64_t(v_pt(1)));
if (dabs < d_min) {
// Previous point.
const Slic3r::Point &p0 = pts[(ipt == 0) ? (pts.size() - 1) : ipt - 1];
Slic3r::Point v_seg_prev = p1 - p0;
int64_t t2_pt = int64_t(v_seg_prev(0)) * int64_t(v_pt(0)) + int64_t(v_seg_prev(1)) * int64_t(v_pt(1));
if (t2_pt > 0) {
// Inside the wedge between the previous and the next segment.
d_min = dabs;
// Set the signum depending on whether the vertex is convex or reflex.
int64_t det = int64_t(v_seg_prev(0)) * int64_t(v_seg(1)) - int64_t(v_seg_prev(1)) * int64_t(v_seg(0));
assert(det != 0);
sign_min = (det > 0) ? 1 : -1;
on_segment = false;
}
}
}
else if (t_pt > l2_seg) {
// Closest to p2. Then p2 is the starting point of another segment, which shall be discovered in the same cell.
continue;
} else {
// Closest to the segment.
assert(t_pt >= 0 && t_pt <= l2_seg);
int64_t d_seg = int64_t(v_seg(1)) * int64_t(v_pt(0)) - int64_t(v_seg(0)) * int64_t(v_pt(1));
double d = double(d_seg) / sqrt(double(l2_seg));
double dabs = std::abs(d);
if (dabs < d_min) {
d_min = dabs;
sign_min = (d_seg < 0) ? -1 : ((d_seg == 0) ? 0 : 1);
on_segment = true;
}
}
}
}
}
if (d_min >= search_radius)
return false;
result_min_dist = d_min * sign_min;
if (pon_segment != NULL)
*pon_segment = on_segment;
return true;
}
bool EdgeGrid::Grid::signed_distance(const Point &pt, coord_t search_radius, coordf_t &result_min_dist) const
{
if (signed_distance_edges(pt, search_radius, result_min_dist))
return true;
if (m_signed_distance_field.empty())
return false;
result_min_dist = signed_distance_bilinear(pt);
return true;
}
Polygons EdgeGrid::Grid::contours_simplified(coord_t offset, bool fill_holes) const
{
assert(std::abs(2 * offset) < m_resolution);
typedef std::unordered_multimap<Point, int, PointHash> EndPointMapType;
// 0) Prepare a binary grid.
size_t cell_rows = m_rows + 2;
size_t cell_cols = m_cols + 2;
std::vector<char> cell_inside(cell_rows * cell_cols, false);
for (int r = 0; r < int(cell_rows); ++ r)
for (int c = 0; c < int(cell_cols); ++ c)
cell_inside[r * cell_cols + c] = cell_inside_or_crossing(r - 1, c - 1);
// Fill in empty cells, which have a left / right neighbor filled.
// Fill in empty cells, which have the top / bottom neighbor filled.
if (fill_holes) {
std::vector<char> cell_inside2(cell_inside);
for (int r = 1; r + 1 < int(cell_rows); ++ r) {
for (int c = 1; c + 1 < int(cell_cols); ++ c) {
int addr = r * cell_cols + c;
if ((cell_inside2[addr - 1] && cell_inside2[addr + 1]) ||
(cell_inside2[addr - cell_cols] && cell_inside2[addr + cell_cols]))
cell_inside[addr] = true;
}
}
}
// 1) Collect the lines.
std::vector<Line> lines;
EndPointMapType start_point_to_line_idx;
for (int r = 0; r <= int(m_rows); ++ r) {
for (int c = 0; c <= int(m_cols); ++ c) {
int addr = (r + 1) * cell_cols + c + 1;
bool left = cell_inside[addr - 1];
bool top = cell_inside[addr - cell_cols];
bool current = cell_inside[addr];
if (left != current) {
lines.push_back(
left ?
Line(Point(c, r+1), Point(c, r )) :
Line(Point(c, r ), Point(c, r+1)));
start_point_to_line_idx.insert(std::pair<Point, int>(lines.back().a, int(lines.size()) - 1));
}
if (top != current) {
lines.push_back(
top ?
Line(Point(c , r), Point(c+1, r)) :
Line(Point(c+1, r), Point(c , r)));
start_point_to_line_idx.insert(std::pair<Point, int>(lines.back().a, int(lines.size()) - 1));
}
}
}
// 2) Chain the lines.
std::vector<char> line_processed(lines.size(), false);
Polygons out;
for (int i_candidate = 0; i_candidate < int(lines.size()); ++ i_candidate) {
if (line_processed[i_candidate])
continue;
Polygon poly;
line_processed[i_candidate] = true;
poly.points.push_back(lines[i_candidate].b);
int i_line_current = i_candidate;
for (;;) {
std::pair<EndPointMapType::iterator,EndPointMapType::iterator> line_range =
start_point_to_line_idx.equal_range(lines[i_line_current].b);
// The interval has to be non empty, there shall be at least one line continuing the current one.
assert(line_range.first != line_range.second);
int i_next = -1;
for (EndPointMapType::iterator it = line_range.first; it != line_range.second; ++ it) {
if (it->second == i_candidate) {
// closing the loop.
goto end_of_poly;
}
if (line_processed[it->second])
continue;
if (i_next == -1) {
i_next = it->second;
} else {
// This is a corner, where two lines meet exactly. Pick the line, which encloses a smallest angle with
// the current edge.
const Line &line_current = lines[i_line_current];
const Line &line_next = lines[it->second];
const Vector v1 = line_current.vector();
const Vector v2 = line_next.vector();
int64_t cross = int64_t(v1(0)) * int64_t(v2(1)) - int64_t(v2(0)) * int64_t(v1(1));
if (cross > 0) {
// This has to be a convex right angle. There is no better next line.
i_next = it->second;
break;
}
}
}
line_processed[i_next] = true;
i_line_current = i_next;
poly.points.push_back(lines[i_line_current].b);
}
end_of_poly:
out.push_back(std::move(poly));
}
// 3) Scale the polygons back into world, shrink slightly and remove collinear points.
for (size_t i = 0; i < out.size(); ++ i) {
Polygon &poly = out[i];
for (size_t j = 0; j < poly.points.size(); ++ j) {
Point &p = poly.points[j];
p(0) *= m_resolution;
p(1) *= m_resolution;
p(0) += m_bbox.min(0);
p(1) += m_bbox.min(1);
}
// Shrink the contour slightly, so if the same contour gets discretized and simplified again, one will get the same result.
// Remove collineaer points.
Points pts;
pts.reserve(poly.points.size());
for (size_t j = 0; j < poly.points.size(); ++ j) {
size_t j0 = (j == 0) ? poly.points.size() - 1 : j - 1;
size_t j2 = (j + 1 == poly.points.size()) ? 0 : j + 1;
Point v = poly.points[j2] - poly.points[j0];
if (v(0) != 0 && v(1) != 0) {
// This is a corner point. Copy it to the output contour.
Point p = poly.points[j];
p(1) += (v(0) < 0) ? - offset : offset;
p(0) += (v(1) > 0) ? - offset : offset;
pts.push_back(p);
}
}
poly.points = std::move(pts);
}
return out;
}
std::vector<std::pair<EdgeGrid::Grid::ContourEdge, EdgeGrid::Grid::ContourEdge>> EdgeGrid::Grid::intersecting_edges() const
{
std::vector<std::pair<ContourEdge, ContourEdge>> out;
// For each cell:
for (int r = 0; r < (int)m_rows; ++ r) {
for (int c = 0; c < (int)m_cols; ++ c) {
const Cell &cell = m_cells[r * m_cols + c];
// For each pair of segments in the cell:
for (size_t i = cell.begin; i != cell.end; ++ i) {
const Slic3r::Points &ipts = *m_contours[m_cell_data[i].first];
size_t ipt = m_cell_data[i].second;
// End points of the line segment and their vector.
const Slic3r::Point &ip1 = ipts[ipt];
const Slic3r::Point &ip2 = ipts[(ipt + 1 == ipts.size()) ? 0 : ipt + 1];
for (size_t j = i + 1; j != cell.end; ++ j) {
const Slic3r::Points &jpts = *m_contours[m_cell_data[j].first];
size_t jpt = m_cell_data[j].second;
// End points of the line segment and their vector.
const Slic3r::Point &jp1 = jpts[jpt];
const Slic3r::Point &jp2 = jpts[(jpt + 1 == jpts.size()) ? 0 : jpt + 1];
if (&ipts == &jpts && (&ip1 == &jp2 || &jp1 == &ip2))
// Segments of the same contour share a common vertex.
continue;
if (Geometry::segments_intersect(ip1, ip2, jp1, jp2)) {
// The two segments intersect. Add them to the output.
int jfirst = (&jpts < &ipts) || (&jpts == &ipts && jpt < ipt);
out.emplace_back(jfirst ?
std::make_pair(std::make_pair(&ipts, ipt), std::make_pair(&jpts, jpt)) :
std::make_pair(std::make_pair(&ipts, ipt), std::make_pair(&jpts, jpt)));
}
}
}
}
}
Slic3r::sort_remove_duplicates(out);
return out;
}
bool EdgeGrid::Grid::has_intersecting_edges() const
{
// For each cell:
for (int r = 0; r < (int)m_rows; ++ r) {
for (int c = 0; c < (int)m_cols; ++ c) {
const Cell &cell = m_cells[r * m_cols + c];
// For each pair of segments in the cell:
for (size_t i = cell.begin; i != cell.end; ++ i) {
const Slic3r::Points &ipts = *m_contours[m_cell_data[i].first];
size_t ipt = m_cell_data[i].second;
// End points of the line segment and their vector.
const Slic3r::Point &ip1 = ipts[ipt];
const Slic3r::Point &ip2 = ipts[(ipt + 1 == ipts.size()) ? 0 : ipt + 1];
for (size_t j = i + 1; j != cell.end; ++ j) {
const Slic3r::Points &jpts = *m_contours[m_cell_data[j].first];
size_t jpt = m_cell_data[j].second;
// End points of the line segment and their vector.
const Slic3r::Point &jp1 = jpts[jpt];
const Slic3r::Point &jp2 = jpts[(jpt + 1 == jpts.size()) ? 0 : jpt + 1];
if (! (&ipts == &jpts && (&ip1 == &jp2 || &jp1 == &ip2)) &&
Geometry::segments_intersect(ip1, ip2, jp1, jp2))
return true;
}
}
}
}
return false;
}
void EdgeGrid::save_png(const EdgeGrid::Grid &grid, const BoundingBox &bbox, coord_t resolution, const char *path, size_t scale)
{
coord_t w = (bbox.max(0) - bbox.min(0) + resolution - 1) / resolution;
coord_t h = (bbox.max(1) - bbox.min(1) + resolution - 1) / resolution;
std::vector<uint8_t> pixels(w * h * 3, 0);
const coord_t search_radius = grid.resolution() * 2;
const coord_t display_blend_radius = grid.resolution() * 2;
for (coord_t r = 0; r < h; ++r) {
for (coord_t c = 0; c < w; ++ c) {
unsigned char *pxl = pixels.data() + (((h - r - 1) * w) + c) * 3;
Point pt(c * resolution + bbox.min(0), r * resolution + bbox.min(1));
coordf_t min_dist;
bool on_segment = true;
#if 0
if (grid.signed_distance_edges(pt, search_radius, min_dist, &on_segment)) {
#else
if (grid.signed_distance(pt, search_radius, min_dist)) {
#endif
float s = 255 * std::abs(min_dist) / float(display_blend_radius);
int is = std::max(0, std::min(255, int(floor(s + 0.5f))));
if (min_dist < 0) {
if (on_segment) {
pxl[0] = 255;
pxl[1] = 255 - is;
pxl[2] = 255 - is;
} else {
pxl[0] = 255;
pxl[1] = 0;
pxl[2] = 255 - is;
}
}
else {
if (on_segment) {
pxl[0] = 255 - is;
pxl[1] = 255 - is;
pxl[2] = 255;
} else {
pxl[0] = 255 - is;
pxl[1] = 0;
pxl[2] = 255;
}
}
} else {
pxl[0] = 0;
pxl[1] = 255;
pxl[2] = 0;
}
float gridx = float(pt(0) - grid.bbox().min(0)) / float(grid.resolution());
float gridy = float(pt(1) - grid.bbox().min(1)) / float(grid.resolution());
if (gridx >= -0.4f && gridy >= -0.4f && gridx <= grid.cols() + 0.4f && gridy <= grid.rows() + 0.4f) {
int ix = int(floor(gridx + 0.5f));
int iy = int(floor(gridy + 0.5f));
float dx = gridx - float(ix);
float dy = gridy - float(iy);
float d = sqrt(dx*dx + dy*dy) * float(grid.resolution()) / float(resolution);
if (d < 1.f) {
// Less than 1 pixel from the grid point.
float t = 0.5f + 0.5f * d;
pxl[0] = (unsigned char)(t * pxl[0]);
pxl[1] = (unsigned char)(t * pxl[1]);
pxl[2] = (unsigned char)(t * pxl[2]);
}
}
float dgrid = fabs(min_dist) / float(grid.resolution());
float igrid = floor(dgrid + 0.5f);
dgrid = std::abs(dgrid - igrid) * float(grid.resolution()) / float(resolution);
if (dgrid < 1.f) {
// Less than 1 pixel from the grid point.
float t = 0.5f + 0.5f * dgrid;
pxl[0] = (unsigned char)(t * pxl[0]);
pxl[1] = (unsigned char)(t * pxl[1]);
pxl[2] = (unsigned char)(t * pxl[2]);
if (igrid > 0.f) {
// Other than zero iso contour.
int g = pxl[1] + 255.f * (1.f - t);
pxl[1] = std::min(g, 255);
}
}
}
}
png::write_rgb_to_file_scaled(path, w, h, pixels, scale);
}
// Find all pairs of intersectiong edges from the set of polygons.
std::vector<std::pair<EdgeGrid::Grid::ContourEdge, EdgeGrid::Grid::ContourEdge>> intersecting_edges(const Polygons &polygons)
{
double len = 0;
size_t cnt = 0;
BoundingBox bbox;
for (const Polygon &poly : polygons) {
if (poly.points.size() < 2)
continue;
for (size_t i = 0; i < poly.points.size(); ++ i) {
bbox.merge(poly.points[i]);
size_t j = (i == 0) ? (poly.points.size() - 1) : i - 1;
len += (poly.points[j] - poly.points[i]).cast<double>().norm();
++ cnt;
}
}
std::vector<std::pair<EdgeGrid::Grid::ContourEdge, EdgeGrid::Grid::ContourEdge>> out;
if (cnt > 0) {
len /= double(cnt);
bbox.offset(20);
EdgeGrid::Grid grid;
grid.set_bbox(bbox);
grid.create(polygons, len);
out = grid.intersecting_edges();
}
return out;
}
// Find all pairs of intersectiong edges from the set of polygons, highlight them in an SVG.
void export_intersections_to_svg(const std::string &filename, const Polygons &polygons)
{
std::vector<std::pair<EdgeGrid::Grid::ContourEdge, EdgeGrid::Grid::ContourEdge>> intersections = intersecting_edges(polygons);
BoundingBox bbox = get_extents(polygons);
SVG svg(filename.c_str(), bbox);
svg.draw(union_ex(polygons), "gray", 0.25f);
svg.draw_outline(polygons, "black");
std::set<const Points*> intersecting_contours;
for (const std::pair<EdgeGrid::Grid::ContourEdge, EdgeGrid::Grid::ContourEdge> &ie : intersections) {
intersecting_contours.insert(ie.first.first);
intersecting_contours.insert(ie.second.first);
}
// Highlight the contours with intersections.
coord_t line_width = coord_t(scale_(0.01));
for (const Points *ic : intersecting_contours) {
svg.draw_outline(Polygon(*ic), "green");
svg.draw_outline(Polygon(*ic), "black", line_width);
}
// Paint the intersections.
for (const std::pair<EdgeGrid::Grid::ContourEdge, EdgeGrid::Grid::ContourEdge> &intersecting_edges : intersections) {
auto edge = [](const EdgeGrid::Grid::ContourEdge &e) {
return Line(e.first->at(e.second),
e.first->at((e.second + 1 == e.first->size()) ? 0 : e.second + 1));
};
svg.draw(edge(intersecting_edges.first), "red", line_width);
svg.draw(edge(intersecting_edges.second), "red", line_width);
}
svg.Close();
}
} // namespace Slic3r