dust3d/thirdparty/carve-1.4.0/lib/triangulator.cpp

1205 lines
35 KiB
C++

// Begin License:
// Copyright (C) 2006-2008 Tobias Sargeant (tobias.sargeant@gmail.com).
// All rights reserved.
//
// This file is part of the Carve CSG Library (http://carve-csg.com/)
//
// This file may be used under the terms of the GNU General Public
// License version 2.0 as published by the Free Software Foundation
// and appearing in the file LICENSE.GPL2 included in the packaging of
// this file.
//
// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE.
// End:
#if defined(HAVE_CONFIG_H)
# include <carve_config.h>
#endif
#include <carve/csg.hpp>
#include <carve/triangulator.hpp>
#include <fstream>
#include <sstream>
#include <algorithm>
namespace {
// private code related to hole patching.
class order_h_loops_2d {
const std::vector<std::vector<carve::geom2d::P2> > &poly;
int axis;
public:
order_h_loops_2d(const std::vector<std::vector<carve::geom2d::P2> > &_poly, int _axis) :
poly(_poly), axis(_axis) {
}
bool operator()(const std::pair<size_t, size_t> &a,
const std::pair<size_t, size_t> &b) const {
return carve::triangulate::detail::axisOrdering(poly[a.first][a.second], poly[b.first][b.second], axis);
}
};
class heap_ordering_2d {
const std::vector<std::vector<carve::geom2d::P2> > &poly;
const std::vector<std::pair<size_t, size_t> > &loop;
const carve::geom2d::P2 p;
int axis;
public:
heap_ordering_2d(const std::vector<std::vector<carve::geom2d::P2> > &_poly,
const std::vector<std::pair<size_t, size_t> > &_loop,
const carve::geom2d::P2 _p,
int _axis) : poly(_poly), loop(_loop), p(_p), axis(_axis) {
}
bool operator()(size_t a, size_t b) const {
double da = carve::geom::distance2(p, poly[loop[a].first][loop[a].second]);
double db = carve::geom::distance2(p, poly[loop[b].first][loop[b].second]);
if (da > db) return true;
if (da < db) return false;
return carve::triangulate::detail::axisOrdering(poly[loop[a].first][loop[a].second], poly[loop[b].first][loop[b].second], axis);
}
};
static inline void patchHoleIntoPolygon_2d(std::vector<std::pair<size_t, size_t> > &f_loop,
size_t f_loop_attach,
size_t h_loop,
size_t h_loop_attach,
size_t h_loop_size) {
f_loop.insert(f_loop.begin() + f_loop_attach + 1, h_loop_size + 2, std::make_pair(h_loop, 0));
size_t f = f_loop_attach + 1;
for (size_t h = h_loop_attach; h != h_loop_size; ++h) {
f_loop[f++].second = h;
}
for (size_t h = 0; h <= h_loop_attach; ++h) {
f_loop[f++].second = h;
}
f_loop[f] = f_loop[f_loop_attach];
}
static inline const carve::geom2d::P2 &pvert(const std::vector<std::vector<carve::geom2d::P2> > &poly, const std::pair<size_t, size_t> &idx) {
return poly[idx.first][idx.second];
}
}
namespace {
// private code related to triangulation.
using carve::triangulate::detail::vertex_info;
struct vertex_info_ordering {
bool operator()(const vertex_info *a, const vertex_info *b) const {
return a->score < b->score;
}
};
struct vertex_info_l2norm_inc_ordering {
const vertex_info *v;
vertex_info_l2norm_inc_ordering(const vertex_info *_v) : v(_v) {
}
bool operator()(const vertex_info *a, const vertex_info *b) const {
return carve::geom::distance2(v->p, a->p) > carve::geom::distance2(v->p, b->p);
}
};
class EarQueue {
std::vector<vertex_info *> queue;
void checkheap() {
//#ifdef __GNUC__
// CARVE_ASSERT(std::__is_heap(queue.begin(), queue.end(), vertex_info_ordering()));
//#endif
}
public:
EarQueue() {
}
size_t size() const {
return queue.size();
}
void push(vertex_info *v) {
#if defined(CARVE_DEBUG)
checkheap();
#endif
queue.push_back(v);
std::push_heap(queue.begin(), queue.end(), vertex_info_ordering());
}
vertex_info *pop() {
#if defined(CARVE_DEBUG)
checkheap();
#endif
std::pop_heap(queue.begin(), queue.end(), vertex_info_ordering());
vertex_info *v = queue.back();
queue.pop_back();
return v;
}
void remove(vertex_info *v) {
#if defined(CARVE_DEBUG)
checkheap();
#endif
CARVE_ASSERT(std::find(queue.begin(), queue.end(), v) != queue.end());
double score = v->score;
if (v != queue[0]) {
v->score = queue[0]->score + 1;
std::make_heap(queue.begin(), queue.end(), vertex_info_ordering());
}
CARVE_ASSERT(v == queue[0]);
std::pop_heap(queue.begin(), queue.end(), vertex_info_ordering());
CARVE_ASSERT(queue.back() == v);
queue.pop_back();
v->score = score;
}
void changeScore(vertex_info *v, double score) {
#if defined(CARVE_DEBUG)
checkheap();
#endif
CARVE_ASSERT(std::find(queue.begin(), queue.end(), v) != queue.end());
if (v->score != score) {
v->score = score;
std::make_heap(queue.begin(), queue.end(), vertex_info_ordering());
}
}
// 39% of execution time
void updateVertex(vertex_info *v) {
double spre = v->score;
bool qpre = v->isCandidate();
v->recompute();
bool qpost = v->isCandidate();
double spost = v->score;
v->score = spre;
if (qpre) {
if (qpost) {
if (v->score != spre) {
changeScore(v, spost);
}
} else {
remove(v);
}
} else {
if (qpost) {
push(v);
}
}
}
};
int windingNumber(vertex_info *begin, const carve::geom2d::P2 &point) {
int wn = 0;
vertex_info *v = begin;
do {
if (v->p.y <= point.y) {
if (v->next->p.y > point.y && carve::geom2d::orient2d(v->p, v->next->p, point) > 0.0) {
++wn;
}
} else {
if (v->next->p.y <= point.y && carve::geom2d::orient2d(v->p, v->next->p, point) < 0.0) {
--wn;
}
}
v = v->next;
} while (v != begin);
return wn;
}
bool internalToAngle(const vertex_info *a,
const vertex_info *b,
const vertex_info *c,
const carve::geom2d::P2 &p) {
return carve::geom2d::internalToAngle(a->p, b->p, c->p, p);
}
bool findDiagonal(vertex_info *begin, vertex_info *&v1, vertex_info *&v2) {
vertex_info *t;
std::vector<vertex_info *> heap;
v1 = begin;
do {
heap.clear();
for (v2 = v1->next->next; v2 != v1->prev; v2 = v2->next) {
if (!internalToAngle(v1->next, v1, v1->prev, v2->p) ||
!internalToAngle(v2->next, v2, v2->prev, v1->p)) continue;
heap.push_back(v2);
std::push_heap(heap.begin(), heap.end(), vertex_info_l2norm_inc_ordering(v1));
}
while (heap.size()) {
std::pop_heap(heap.begin(), heap.end(), vertex_info_l2norm_inc_ordering(v1));
v2 = heap.back(); heap.pop_back();
#if defined(CARVE_DEBUG)
std::cerr << "testing: " << v1 << " - " << v2 << std::endl;
std::cerr << " length = " << (v2->p - v1->p).length() << std::endl;
std::cerr << " pos: " << v1->p << " - " << v2->p << std::endl;
#endif
// test whether v1-v2 is a valid diagonal.
double v_min_x = std::min(v1->p.x, v2->p.x);
double v_max_x = std::max(v1->p.x, v2->p.x);
bool intersected = false;
for (t = v1->next; !intersected && t != v1->prev; t = t->next) {
vertex_info *u = t->next;
if (t == v2 || u == v2) continue;
double l1 = carve::geom2d::orient2d(v1->p, v2->p, t->p);
double l2 = carve::geom2d::orient2d(v1->p, v2->p, u->p);
if ((l1 > 0.0 && l2 > 0.0) || (l1 < 0.0 && l2 < 0.0)) {
// both on the same side; no intersection
continue;
}
double dx13 = v1->p.x - t->p.x;
double dy13 = v1->p.y - t->p.y;
double dx43 = u->p.x - t->p.x;
double dy43 = u->p.y - t->p.y;
double dx21 = v2->p.x - v1->p.x;
double dy21 = v2->p.y - v1->p.y;
double ua_n = dx43 * dy13 - dy43 * dx13;
double ub_n = dx21 * dy13 - dy21 * dx13;
double u_d = dy43 * dx21 - dx43 * dy21;
if (carve::math::ZERO(u_d)) {
// parallel
if (carve::math::ZERO(ua_n)) {
// colinear
if (std::max(t->p.x, u->p.x) >= v_min_x && std::min(t->p.x, u->p.x) <= v_max_x) {
// colinear and intersecting
intersected = true;
}
}
} else {
// not parallel
double ua = ua_n / u_d;
double ub = ub_n / u_d;
if (0.0 <= ua && ua <= 1.0 && 0.0 <= ub && ub <= 1.0) {
intersected = true;
}
}
#if defined(CARVE_DEBUG)
if (intersected) {
std::cerr << " failed on edge: " << t << " - " << u << std::endl;
std::cerr << " pos: " << t->p << " - " << u->p << std::endl;
}
#endif
}
if (!intersected) {
// test whether midpoint winding == 1
carve::geom2d::P2 mid = (v1->p + v2->p) / 2;
if (windingNumber(begin, mid) == 1) {
// this diagonal is ok
return true;
}
}
}
// couldn't find a diagonal from v1 that was ok.
v1 = v1->next;
} while (v1 != begin);
return false;
}
#if defined(CARVE_DEBUG_WRITE_PLY_DATA)
void dumpPoly(const std::vector<carve::geom2d::P2> &points,
const std::vector<carve::triangulate::tri_idx> &result) {
static int step = 0;
std::ostringstream filename;
filename << "poly_" << step++ << ".svg";
std::cerr << "dumping to " << filename.str() << std::endl;
std::ofstream out(filename.str().c_str());
double minx = points[0].x, maxx = points[0].x;
double miny = points[0].y, maxy = points[0].y;
for (size_t i = 1; i < points.size(); ++i) {
minx = std::min(points[i].x, minx); maxx = std::max(points[i].x, maxx);
miny = std::min(points[i].y, miny); maxy = std::max(points[i].y, maxy);
}
double scale = 100 / std::max(maxx-minx, maxy-miny);
maxx *= scale; minx *= scale;
maxy *= scale; miny *= scale;
double width = maxx - minx + 10;
double height = maxy - miny + 10;
out << "\
<?xml version=\"1.0\"?>\n\
<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\" \"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\">\n\
<svg xmlns=\"http://www.w3.org/2000/svg\" version=\"1.1\" width=\"" << width << "\" height=\"" << height << "\">\n";
out << "<polygon fill=\"rgb(0,0,0)\" stroke=\"blue\" stroke-width=\"0.1\" points=\"";
for (size_t i = 0; i < points.size(); ++i) {
if (i) out << ' ';
double x, y;
x = scale * (points[i].x) - minx + 5;
y = scale * (points[i].y) - miny + 5;
out << x << ',' << y;
}
out << "\" />" << std::endl;
for (size_t i = 0; i < result.size(); ++i) {
out << "<polygon fill=\"rgb(255,255,255)\" stroke=\"black\" stroke-width=\"0.1\" points=\"";
double x, y;
x = scale * (points[result[i].a].x) - minx + 5;
y = scale * (points[result[i].a].y) - miny + 5;
out << x << ',' << y << ' ';
x = scale * (points[result[i].b].x) - minx + 5;
y = scale * (points[result[i].b].y) - miny + 5;
out << x << ',' << y << ' ';
x = scale * (points[result[i].c].x) - minx + 5;
y = scale * (points[result[i].c].y) - miny + 5;
out << x << ',' << y;
out << "\" />" << std::endl;
}
out << "</svg>" << std::endl;
}
#endif
}
double carve::triangulate::detail::vertex_info::triScore(const vertex_info *p, const vertex_info *v, const vertex_info *n) {
// different scoring functions.
#if 0
bool convex = isLeft(p, v, n);
if (!convex) return -1e-5;
double a1 = carve::geom2d::atan2(p->p - v->p) - carve::geom2d::atan2(n->p - v->p);
double a2 = carve::geom2d::atan2(v->p - n->p) - carve::geom2d::atan2(p->p - n->p);
if (a1 < 0) a1 += M_PI * 2;
if (a2 < 0) a2 += M_PI * 2;
return std::min(a1, std::min(a2, M_PI - a1 - a2)) / (M_PI / 3);
#endif
#if 1
// range: 0 - 1
double a, b, c;
bool convex = isLeft(p, v, n);
if (!convex) return -1e-5;
a = (n->p - v->p).length();
b = (p->p - n->p).length();
c = (v->p - p->p).length();
if (a < 1e-10 || b < 1e-10 || c < 1e-10) return 0.0;
return std::max(std::min((a+b)/c, std::min((a+c)/b, (b+c)/a)) - 1.0, 0.0);
#endif
}
double carve::triangulate::detail::vertex_info::calcScore() const {
#if 0
// examine only this triangle.
double this_tri = triScore(prev, this, next);
return this_tri;
#endif
#if 1
// attempt to look ahead in the neighbourhood to attempt to clip ears that have good neighbours.
double this_tri = triScore(prev, this, next);
double next_tri = triScore(prev, next, next->next);
double prev_tri = triScore(prev->prev, prev, next);
return this_tri + std::max(next_tri, prev_tri) * .2;
#endif
#if 0
// attempt to penalise ears that will require producing a sliver triangle.
double score = triScore(prev, this, next);
double a1, a2;
a1 = carve::geom2d::atan2(prev->p - next->p);
a2 = carve::geom2d::atan2(next->next->p - next->p);
if (fabs(a1 - a2) < 1e-5) score -= .5;
a1 = carve::geom2d::atan2(next->p - prev->p);
a2 = carve::geom2d::atan2(prev->prev->p - prev->p);
if (fabs(a1 - a2) < 1e-5) score -= .5;
return score;
#endif
}
bool carve::triangulate::detail::vertex_info::isClipable() const {
for (const vertex_info *v_test = next->next; v_test != prev; v_test = v_test->next) {
if (v_test->convex) {
continue;
}
if (v_test->p == prev->p ||
v_test->p == next->p) {
continue;
}
if (v_test->p == p) {
if (v_test->next->p == prev->p &&
v_test->prev->p == next->p) {
return false;
}
if (v_test->next->p == prev->p ||
v_test->prev->p == next->p) {
continue;
}
}
if (pointInTriangle(prev, this, next, v_test)) {
return false;
}
}
return true;
}
size_t carve::triangulate::detail::removeDegeneracies(vertex_info *&begin, std::vector<carve::triangulate::tri_idx> &result) {
vertex_info *v = begin;
vertex_info *n;
size_t count = 0;
do {
bool remove = false;
if (v->p == v->next->p) {
remove = true;
} else if (v->p == v->next->next->p) {
if (v->next->p == v->next->next->next->p) {
// a 'z' in the loop: z (a) b a b c -> remove a-b-a -> z (a) a b c -> remove a-a-b (next loop) -> z a b c
// z --(a)-- b
// /
// /
// a -- b -- d
remove = true;
} else {
// a 'shard' in the loop: z (a) b a c d -> remove a-b-a -> z (a) a b c d -> remove a-a-b (next loop) -> z a b c d
// z --(a)-- b
// /
// /
// a -- c -- d
// n.b. can only do this if the shard is pointing out of the polygon. i.e. b is outside z-a-c
remove = !internalToAngle(v->next->next->next, v, v->prev, v->next->p);
}
}
if (remove) {
result.push_back(carve::triangulate::tri_idx(v->idx, v->next->idx, v->next->next->idx));
n = v->next;
if (n == begin) begin = n->next;
n->remove();
count++;
delete n;
continue;
}
v = v->next;
} while (v != begin);
return count;
}
bool carve::triangulate::detail::splitAndResume(vertex_info *begin, std::vector<carve::triangulate::tri_idx> &result) {
vertex_info *v1, *v2;
#if defined(CARVE_DEBUG_WRITE_PLY_DATA)
{
std::vector<carve::triangulate::tri_idx> dummy;
std::vector<carve::geom2d::P2> dummy_p;
vertex_info *v = begin;
do {
dummy_p.push_back(v->p);
v = v->next;
} while (v != begin);
std::cerr << "input to splitAndResume:" << std::endl;
dumpPoly(dummy_p, dummy);
}
#endif
if (!findDiagonal(begin, v1, v2)) return false;
vertex_info *v1_copy = new vertex_info(*v1);
vertex_info *v2_copy = new vertex_info(*v2);
v1->next = v2;
v2->prev = v1;
v1_copy->next->prev = v1_copy;
v2_copy->prev->next = v2_copy;
v1_copy->prev = v2_copy;
v2_copy->next = v1_copy;
bool r1 = doTriangulate(v1, result);
bool r2 = doTriangulate(v1_copy, result);
return r1 && r2;
}
bool carve::triangulate::detail::doTriangulate(vertex_info *begin, std::vector<carve::triangulate::tri_idx> &result) {
#if defined(CARVE_DEBUG)
std::cerr << "entering doTriangulate" << std::endl;
#endif
#if defined(CARVE_DEBUG_WRITE_PLY_DATA)
{
std::vector<carve::triangulate::tri_idx> dummy;
std::vector<carve::geom2d::P2> dummy_p;
vertex_info *v = begin;
do {
dummy_p.push_back(v->p);
v = v->next;
} while (v != begin);
dumpPoly(dummy_p, dummy);
}
#endif
EarQueue vq;
vertex_info *v = begin;
size_t remain = 0;
do {
if (v->isCandidate()) vq.push(v);
v = v->next;
remain++;
} while (v != begin);
#if defined(CARVE_DEBUG)
std::cerr << "remain = " << remain << std::endl;
#endif
while (vq.size()) {
vertex_info *v = vq.pop();
if (!v->isClipable()) {
v->failed = true;
continue;
}
continue_clipping:
vertex_info *n = v->next;
vertex_info *p = v->prev;
result.push_back(carve::triangulate::tri_idx(v->prev->idx, v->idx, v->next->idx));
#if defined(CARVE_DEBUG)
{
std::vector<carve::geom2d::P2> temp;
temp.push_back(v->prev->p);
temp.push_back(v->p);
temp.push_back(v->next->p);
std::cerr << "clip " << v << " idx = " << v->idx << " score = " << v->score << " area = " << carve::geom2d::signedArea(temp) << " " << temp[0] << " " << temp[1] << " " << temp[2] << std::endl;
}
#endif
v->remove();
remain--;
if (v == begin) begin = v->next;
delete v;
vq.updateVertex(n);
vq.updateVertex(p);
if (n->score < p->score) { std::swap(n, p); }
if (n->score > 0.25 && n->isCandidate() && n->isClipable()) {
vq.remove(n);
v = n;
#if defined(CARVE_DEBUG)
std::cerr << " continue clipping (n), score = " << n->score << std::endl;
#endif
goto continue_clipping;
}
if (p->score > 0.25 && p->isCandidate() && p->isClipable()) {
vq.remove(p);
v = p;
#if defined(CARVE_DEBUG)
std::cerr << " continue clipping (p), score = " << n->score << std::endl;
#endif
goto continue_clipping;
}
#if defined(CARVE_DEBUG)
std::cerr << "looking for new start point" << std::endl;
std::cerr << "remain = " << remain << std::endl;
#endif
}
#if defined(CARVE_DEBUG)
std::cerr << "doTriangulate complete; remain=" << remain << std::endl;
#endif
bool ret;
if (remain > 3) {
std::vector<carve::geom2d::P2> temp;
temp.reserve(remain);
vertex_info *v = begin;
do {
temp.push_back(v->p);
v = v->next;
} while (v != begin);
if (carve::geom2d::signedArea(temp) == 0) {
// XXX: this test will fail in cases where the boundary is
// twisted so that a negative area balances a positive area.
#if defined(CARVE_DEBUG)
std::cerr << "skeleton remains. complete." << std::endl;
#endif
goto done;
}
#if defined(CARVE_DEBUG)
std::cerr << "before removeDegeneracies: remain=" << remain << std::endl;
#endif
remain -= removeDegeneracies(begin, result);
#if defined(CARVE_DEBUG)
std::cerr << "after removeDegeneracies: remain=" << remain << std::endl;
#endif
}
if (remain > 3) {
return splitAndResume(begin, result);
} else if (remain == 3) {
result.push_back(carve::triangulate::tri_idx(begin->idx, begin->next->idx, begin->next->next->idx));
ret = true;
} else {
ret = true;
}
done:
vertex_info *d = begin;
do {
vertex_info *n = d->next;
delete d;
d = n;
} while (d != begin);
return ret;
}
bool testCandidateAttachment(const std::vector<std::vector<carve::geom2d::P2> > &poly,
std::vector<std::pair<size_t, size_t> > &current_f_loop,
size_t curr,
carve::geom2d::P2 hole_min) {
const size_t SZ = current_f_loop.size();
if (!carve::geom2d::internalToAngle(pvert(poly, current_f_loop[(curr+1) % SZ]),
pvert(poly, current_f_loop[curr]),
pvert(poly, current_f_loop[(curr+SZ-1) % SZ]),
hole_min)) {
return false;
}
carve::geom2d::LineSegment2 test(hole_min, pvert(poly, current_f_loop[curr]));
size_t v1 = current_f_loop.size() - 1;
size_t v2 = 0;
int v1_side = carve::geom2d::orient2d(test.v1, test.v2, pvert(poly, current_f_loop[v1]));
int v2_side = 0;
while (v2 != current_f_loop.size()) {
v2_side = carve::geom2d::orient2d(test.v1, test.v2, pvert(poly, current_f_loop[v2]));
if (v1_side != v2_side) {
// XXX: need to test vertices, not indices, because they may
// be duplicated.
if (pvert(poly, current_f_loop[v1]) != pvert(poly, current_f_loop[curr]) &&
pvert(poly, current_f_loop[v2]) != pvert(poly, current_f_loop[curr])) {
carve::geom2d::LineSegment2 test2(pvert(poly, current_f_loop[v1]), pvert(poly, current_f_loop[v2]));
carve::LineIntersectionClass ic = carve::geom2d::lineSegmentIntersection(test, test2).iclass;
if (ic > 0) {
// intersection; failed.
return false;
}
}
}
v1 = v2;
v1_side = v2_side;
++v2;
}
return true;
}
void
carve::triangulate::incorporateHolesIntoPolygon(
const std::vector<std::vector<carve::geom2d::P2> > &poly,
std::vector<std::pair<size_t, size_t> > &result,
size_t poly_loop,
const std::vector<size_t> &hole_loops) {
typedef std::vector<carve::geom2d::P2> loop_t;
size_t N = poly[poly_loop].size();
// work out how much space to reserve for the patched in holes.
for (size_t i = 0; i < hole_loops.size(); i++) {
N += 2 + poly[hole_loops[i]].size();
}
// this is the vector that we will build the result in.
result.clear();
result.reserve(N);
// this is a heap of result indices that defines the vertex test order.
std::vector<size_t> f_loop_heap;
f_loop_heap.reserve(N);
// add the poly loop to result.
for (size_t i = 0; i < poly[poly_loop].size(); ++i) {
result.push_back(std::make_pair((size_t)poly_loop, i));
}
if (hole_loops.size() == 0) {
return;
}
std::vector<std::pair<size_t, size_t> > h_loop_min_vertex;
h_loop_min_vertex.reserve(hole_loops.size());
// find the major axis for the holes - this is the axis that we
// will sort on for finding vertices on the polygon to join
// holes up to.
//
// it might also be nice to also look for whether it is better
// to sort ascending or descending.
//
// another trick that could be used is to modify the projection
// by 90 degree rotations or flipping about an axis. just as
// long as we keep the carve::geom3d::Vector pointers for the
// real data in sync, everything should be ok. then we wouldn't
// need to accomodate axes or sort order in the main loop.
// find the bounding box of all the holes.
carve::geom2d::P2 h_min, h_max;
h_min = h_max = poly[hole_loops[0]][0];
for (size_t i = 0; i < hole_loops.size(); ++i) {
const loop_t &hole = poly[hole_loops[i]];
for (size_t j = 0; j < hole.size(); ++j) {
assign_op(h_min, h_min, hole[j], carve::util::min_functor());
assign_op(h_max, h_max, hole[j], carve::util::max_functor());
}
}
// choose the axis for which the bbox is largest.
int axis = (h_max.x - h_min.x) > (h_max.y - h_min.y) ? 0 : 1;
// for each hole, find the minimum vertex in the chosen axis.
for (size_t i = 0; i < hole_loops.size(); ++i) {
const loop_t &hole = poly[hole_loops[i]];
size_t best, curr;
best = 0;
for (curr = 1; curr != hole.size(); ++curr) {
if (detail::axisOrdering(hole[curr], hole[best], axis)) {
best = curr;
}
}
h_loop_min_vertex.push_back(std::make_pair(hole_loops[i], best));
}
// sort the holes by the minimum vertex.
std::sort(h_loop_min_vertex.begin(), h_loop_min_vertex.end(), order_h_loops_2d(poly, axis));
// now, for each hole, find a vertex in the current polygon loop that it can be joined to.
for (unsigned i = 0; i < h_loop_min_vertex.size(); ++i) {
// the index of the vertex in the hole to connect.
size_t hole_i = h_loop_min_vertex[i].first;
size_t hole_i_connect = h_loop_min_vertex[i].second;
carve::geom2d::P2 hole_min = poly[hole_i][hole_i_connect];
f_loop_heap.clear();
// we order polygon loop vertices that may be able to be connected
// to the hole vertex by their distance to the hole vertex
heap_ordering_2d _heap_ordering(poly, result, hole_min, axis);
const size_t SZ = result.size();
for (size_t j = 0; j < SZ; ++j) {
// it is guaranteed that there exists a polygon vertex with
// coord < the min hole coord chosen, which can be joined to
// the min hole coord without crossing the polygon
// boundary. also, because we merge holes in ascending
// order, it is also true that this join can never cross
// another hole (and that doesn't need to be tested for).
if (pvert(poly, result[j]).v[axis] < hole_min.v[axis]) {
f_loop_heap.push_back(j);
std::push_heap(f_loop_heap.begin(), f_loop_heap.end(), _heap_ordering);
}
}
// we are going to test each potential (according to the
// previous test) polygon vertex as a candidate join. we order
// by closeness to the hole vertex, so that the join we make
// is as small as possible. to test, we need to check the
// joining line segment does not cross any other line segment
// in the current polygon loop (excluding those that have the
// vertex that we are attempting to join with as an endpoint).
size_t attachment_point = result.size();
while (f_loop_heap.size()) {
std::pop_heap(f_loop_heap.begin(), f_loop_heap.end(), _heap_ordering);
size_t curr = f_loop_heap.back();
f_loop_heap.pop_back();
// test the candidate join from result[curr] to hole_min
if (!testCandidateAttachment(poly, result, curr, hole_min)) {
continue;
}
attachment_point = curr;
break;
}
if (attachment_point == result.size()) {
CARVE_FAIL("didn't manage to link up hole!");
}
patchHoleIntoPolygon_2d(result, attachment_point, hole_i, hole_i_connect, poly[hole_i].size());
}
}
std::vector<std::pair<size_t, size_t> >
carve::triangulate::incorporateHolesIntoPolygon(const std::vector<std::vector<carve::geom2d::P2> > &poly) {
#if 1
std::vector<std::pair<size_t, size_t> > result;
std::vector<size_t> hole_indices;
hole_indices.reserve(poly.size() - 1);
for (size_t i = 1; i < poly.size(); ++i) {
hole_indices.push_back(i);
}
incorporateHolesIntoPolygon(poly, result, 0, hole_indices);
return result;
#else
typedef std::vector<carve::geom2d::P2> loop_t;
size_t N = poly[0].size();
//
// work out how much space to reserve for the patched in holes.
for (size_t i = 0; i < poly.size(); i++) {
N += 2 + poly[i].size();
}
// this is the vector that we will build the result in.
std::vector<std::pair<size_t, size_t> > current_f_loop;
current_f_loop.reserve(N);
// this is a heap of current_f_loop indices that defines the vertex test order.
std::vector<size_t> f_loop_heap;
f_loop_heap.reserve(N);
// add the poly loop to current_f_loop.
for (size_t i = 0; i < poly[0].size(); ++i) {
current_f_loop.push_back(std::make_pair((size_t)0, i));
}
if (poly.size() == 1) {
return current_f_loop;
}
std::vector<std::pair<size_t, size_t> > h_loop_min_vertex;
h_loop_min_vertex.reserve(poly.size() - 1);
// find the major axis for the holes - this is the axis that we
// will sort on for finding vertices on the polygon to join
// holes up to.
//
// it might also be nice to also look for whether it is better
// to sort ascending or descending.
//
// another trick that could be used is to modify the projection
// by 90 degree rotations or flipping about an axis. just as
// long as we keep the carve::geom3d::Vector pointers for the
// real data in sync, everything should be ok. then we wouldn't
// need to accomodate axes or sort order in the main loop.
// find the bounding box of all the holes.
double min_x, min_y, max_x, max_y;
min_x = max_x = poly[1][0].x;
min_y = max_y = poly[1][0].y;
for (size_t i = 1; i < poly.size(); ++i) {
const loop_t &hole = poly[i];
for (size_t j = 0; j < hole.size(); ++j) {
min_x = std::min(min_x, hole[j].x);
min_y = std::min(min_y, hole[j].y);
max_x = std::max(max_x, hole[j].x);
max_y = std::max(max_y, hole[j].y);
}
}
// choose the axis for which the bbox is largest.
int axis = (max_x - min_x) > (max_y - min_y) ? 0 : 1;
// for each hole, find the minimum vertex in the chosen axis.
for (size_t i = 1; i < poly.size(); ++i) {
const loop_t &hole = poly[i];
size_t best, curr;
best = 0;
for (curr = 1; curr != hole.size(); ++curr) {
if (detail::axisOrdering(hole[curr], hole[best], axis)) {
best = curr;
}
}
h_loop_min_vertex.push_back(std::make_pair(i, best));
}
// sort the holes by the minimum vertex.
std::sort(h_loop_min_vertex.begin(), h_loop_min_vertex.end(), order_h_loops_2d(poly, axis));
// now, for each hole, find a vertex in the current polygon loop that it can be joined to.
for (unsigned i = 0; i < h_loop_min_vertex.size(); ++i) {
// the index of the vertex in the hole to connect.
size_t hole_i = h_loop_min_vertex[i].first;
size_t hole_i_connect = h_loop_min_vertex[i].second;
carve::geom2d::P2 hole_min = poly[hole_i][hole_i_connect];
f_loop_heap.clear();
// we order polygon loop vertices that may be able to be connected
// to the hole vertex by their distance to the hole vertex
heap_ordering_2d _heap_ordering(poly, current_f_loop, hole_min, axis);
const size_t SZ = current_f_loop.size();
for (size_t j = 0; j < SZ; ++j) {
// it is guaranteed that there exists a polygon vertex with
// coord < the min hole coord chosen, which can be joined to
// the min hole coord without crossing the polygon
// boundary. also, because we merge holes in ascending
// order, it is also true that this join can never cross
// another hole (and that doesn't need to be tested for).
if (pvert(poly, current_f_loop[j]).v[axis] < hole_min.v[axis]) {
f_loop_heap.push_back(j);
std::push_heap(f_loop_heap.begin(), f_loop_heap.end(), _heap_ordering);
}
}
// we are going to test each potential (according to the
// previous test) polygon vertex as a candidate join. we order
// by closeness to the hole vertex, so that the join we make
// is as small as possible. to test, we need to check the
// joining line segment does not cross any other line segment
// in the current polygon loop (excluding those that have the
// vertex that we are attempting to join with as an endpoint).
size_t attachment_point = current_f_loop.size();
while (f_loop_heap.size()) {
std::pop_heap(f_loop_heap.begin(), f_loop_heap.end(), _heap_ordering);
size_t curr = f_loop_heap.back();
f_loop_heap.pop_back();
// test the candidate join from current_f_loop[curr] to hole_min
if (!testCandidateAttachment(poly, current_f_loop, curr, hole_min)) {
continue;
}
attachment_point = curr;
break;
}
if (attachment_point == current_f_loop.size()) {
CARVE_FAIL("didn't manage to link up hole!");
}
patchHoleIntoPolygon_2d(current_f_loop, attachment_point, hole_i, hole_i_connect, poly[hole_i].size());
}
return current_f_loop;
#endif
}
std::vector<std::vector<std::pair<size_t, size_t> > >
carve::triangulate::mergePolygonsAndHoles(const std::vector<std::vector<carve::geom2d::P2> > &poly) {
std::vector<size_t> poly_indices, hole_indices;
poly_indices.reserve(poly.size());
hole_indices.reserve(poly.size());
for (size_t i = 0; i < poly.size(); ++i) {
if (carve::geom2d::signedArea(poly[i]) < 0) {
poly_indices.push_back(i);
} else {
hole_indices.push_back(i);
}
}
std::vector<std::vector<std::pair<size_t, size_t> > > result;
result.resize(poly_indices.size());
if (hole_indices.size() == 0) {
for (size_t i = 0; i < poly.size(); ++i) {
result[i].resize(poly[i].size());
for (size_t j = 0; j < poly[i].size(); ++j) {
result[i].push_back(std::make_pair(i, j));
}
}
return result;
}
if (poly_indices.size() == 1) {
incorporateHolesIntoPolygon(poly, result[0], poly_indices[0], hole_indices);
return result;
}
throw carve::exception("not implemented");
}
void carve::triangulate::triangulate(const std::vector<carve::geom2d::P2> &poly,
std::vector<carve::triangulate::tri_idx> &result) {
std::vector<detail::vertex_info *> vinfo;
const size_t N = poly.size();
#if defined(CARVE_DEBUG)
std::cerr << "TRIANGULATION BEGINS" << std::endl;
#endif
#if defined(CARVE_DEBUG_WRITE_PLY_DATA)
dumpPoly(poly, result);
#endif
result.clear();
if (N < 3) {
return;
}
result.reserve(poly.size() - 2);
if (N == 3) {
result.push_back(tri_idx(0, 1, 2));
return;
}
vinfo.resize(N);
vinfo[0] = new detail::vertex_info(poly[0], 0);
for (size_t i = 1; i < N-1; ++i) {
vinfo[i] = new detail::vertex_info(poly[i], i);
vinfo[i]->prev = vinfo[i-1];
vinfo[i-1]->next = vinfo[i];
}
vinfo[N-1] = new detail::vertex_info(poly[N-1], N-1);
vinfo[N-1]->prev = vinfo[N-2];
vinfo[N-1]->next = vinfo[0];
vinfo[0]->prev = vinfo[N-1];
vinfo[N-2]->next = vinfo[N-1];
for (size_t i = 0; i < N; ++i) {
vinfo[i]->recompute();
}
detail::vertex_info *begin = vinfo[0];
removeDegeneracies(begin, result);
doTriangulate(begin, result);
#if defined(CARVE_DEBUG)
std::cerr << "TRIANGULATION ENDS" << std::endl;
#endif
#if defined(CARVE_DEBUG_WRITE_PLY_DATA)
dumpPoly(poly, result);
#endif
}
void carve::triangulate::detail::tri_pair_t::flip(vert_edge_t &old_edge,
vert_edge_t &new_edge,
vert_edge_t perim[4]) {
unsigned ai, bi;
unsigned cross_ai, cross_bi;
findSharedEdge(ai, bi);
old_edge = ordered_vert_edge_t(a->v[ai], b->v[bi]);
cross_ai = P(ai);
cross_bi = P(bi);
new_edge = ordered_vert_edge_t(a->v[cross_ai], b->v[cross_bi]);
score = -score;
a->v[N(ai)] = b->v[cross_bi];
b->v[N(bi)] = a->v[cross_ai];
perim[0] = ordered_vert_edge_t(a->v[P(ai)], a->v[ai]);
perim[1] = ordered_vert_edge_t(a->v[N(ai)], a->v[ai]); // this edge was a b-edge
perim[2] = ordered_vert_edge_t(b->v[P(bi)], b->v[bi]);
perim[3] = ordered_vert_edge_t(b->v[N(bi)], b->v[bi]); // this edge was an a-edge
}
void carve::triangulate::detail::tri_pairs_t::insert(unsigned a, unsigned b, carve::triangulate::tri_idx *t) {
tri_pair_t *tp;
if (a < b) {
tp = storage[vert_edge_t(a,b)];
if (!tp) {
tp = storage[vert_edge_t(a,b)] = new tri_pair_t;
}
tp->a = t;
} else {
tp = storage[vert_edge_t(b,a)];
if (!tp) {
tp = storage[vert_edge_t(b,a)] = new tri_pair_t;
}
tp->b = t;
}
}