void EarClippingTriangulation::initLists ()
{
// go through points checking ccw, cw or collinear order and identifying ears
std::list<std::size_t>::iterator it (_vertex_list.begin()), prev(_vertex_list.end()), next;
--prev;
next = it;
++next;
GeoLib::Orientation orientation;
bool first_run(true); // saves special handling of the last case with identical code
while (_vertex_list.size() >= 3 && first_run) {
if (next == _vertex_list.end()) {
first_run = false;
next = _vertex_list.begin();
}
orientation = getOrientation (_pnts[*prev], _pnts[*it], _pnts[*next]);
if (orientation == GeoLib::COLLINEAR) {
WARN("EarClippingTriangulation::initLists(): collinear points (%f, %f, %f), (%f, %f, %f), (%f, %f, %f)",
(*_pnts[*prev])[0], (*_pnts[*prev])[1], (*_pnts[*prev])[2],
(*_pnts[*it])[0], (*_pnts[*it])[1], (*_pnts[*it])[2],
(*_pnts[*next])[0], (*_pnts[*next])[1], (*_pnts[*next])[2]);
it = _vertex_list.erase (it);
++next;
} else {
if (orientation == GeoLib::CW) {
_convex_vertex_list.push_back (*it);
if (isEar (*prev, *it, *next))
_ear_list.push_back (*it);
}
prev = it;
it = next;
++next;
}
}
}
void EarClippingTriangulation::initLists ()
{
// go through points checking ccw, cw or collinear order and identifying ears
std::list<size_t>::iterator it (_vertex_list.begin()), prev(_vertex_list.end()), next;
prev--;
next = it;
next++;
MathLib::Orientation orientation;
while (next != _vertex_list.end())
{
orientation = getOrientation (_pnts[*prev], _pnts[*it], _pnts[*next]);
if (orientation == COLLINEAR)
{
it = _vertex_list.erase (it);
next++;
}
else
{
if (orientation == CW)
{
_convex_vertex_list.push_back (*it);
if (isEar (*prev, *it, *next))
_ear_list.push_back (*it);
}
prev = it;
it = next;
next++;
}
}
next = _vertex_list.begin();
orientation = getOrientation (_pnts[*prev], _pnts[*it], _pnts[*next]);
if (orientation == COLLINEAR)
it = _vertex_list.erase (it);
if (orientation == CW)
{
_convex_vertex_list.push_back (*it);
if (isEar (*prev, *it, *next))
_ear_list.push_back (*it);
}
}
PolygonTriangulation EarRemovalAlgorithm::triangulate(const vector<Point2D> & polygon){
int n = polygon.size();
PolygonTriangulation t(polygon);
if(n < 3) return t;
list<int> currPoly; // Lista que armazena os índices do polígono atual do algoritmo de remoção de orelhas
vector<int> isEar(n, 0); // Vetor que armazena indicador de formação de orelha nos pontos do polígono
// Adiciona todos os pontos do polígono na lista de pontos do polígono atual do algoritmo
for(int i=0; i<n; i++){
currPoly.push_back(i);
}
// Determina para cada ponto se no mesmo se forma uma orelha no triângulo formado com seus vizinhos
for(list<int>::iterator it = currPoly.begin(); it != currPoly.end(); it++){
int p = *it;
isEar[p] = checkEar(currPoly, it, polygon);
}
// Equanto não tivermos apenas um triângulo, então removemos ums orelha
while(currPoly.size() > 3){
// Procura uma orelha no polígono atual
for(list<int>::iterator it = currPoly.begin(); it != currPoly.end(); it++){
int p = *it;
if(isEar[p]){
list<int>::iterator prevIt = getPrevIterator(currPoly, it);
list<int>::iterator nextIt = getNextIterator(currPoly, it);
// Determina índice dos pontos da orelha
int p0 = *prevIt;
int p1 = *it;
int p2 = *nextIt;
// Adicioa orelha a triangulação do polígono
t.addTriangle(p0, p1, p2);
// Remove o ponto central do triângulo do polígono
currPoly.erase(it);
// Atualiza o indicador de orelha nos pontos vizinhos de p1 no novo polígono formado após a remoção de p1
isEar[p0] = checkEar(currPoly, prevIt, polygon);
isEar[p2] = checkEar(currPoly, nextIt, polygon);
break;
}
}
}
// Adiciona o triângulo final na triangulação
list<int>::iterator it = currPoly.begin();
int p0 = *it; it++;
int p1 = *it; it++;
int p2 = *it;
t.addTriangle(p0, p1, p2);
return t;
}
void triangulate(const Vertices& vertices, PolygonMesh& output)
{
const int n_vertices = vertices.vertices.size();
if (n_vertices <= 3)
{
output.polygons.push_back(vertices);
return;
}
std::vector<uint32_t> remaining_vertices(n_vertices);
if (area(vertices.vertices) > 0) // clockwise?
{
remaining_vertices = vertices.vertices;
}
else
{
for (int v = 0; v < n_vertices; v++)
remaining_vertices[v] = vertices.vertices[n_vertices - 1 - v];
}
// Avoid closed loops.
if (remaining_vertices.front() == remaining_vertices.back())
remaining_vertices.erase(remaining_vertices.end()-1);
// null_iterations avoids infinite loops if the polygon is not simple.
for (int u = remaining_vertices.size() - 1, null_iterations = 0;
remaining_vertices.size() > 2 && null_iterations < remaining_vertices.size()*2;
++null_iterations, u=(u+1)%remaining_vertices.size())
{
int v = (u + 1) % remaining_vertices.size();
int w = (u + 2) % remaining_vertices.size();
if (isEar(u, v, w, remaining_vertices))
{
Vertices triangle;
triangle.vertices.resize(3);
triangle.vertices[0] = remaining_vertices[u];
triangle.vertices[1] = remaining_vertices[v];
triangle.vertices[2] = remaining_vertices[w];
output.polygons.push_back(triangle);
remaining_vertices.erase(remaining_vertices.begin()+v);
null_iterations = 0;
}
}
for (int i = 0; i < remaining_vertices.size(); ++i)
ntk_dbg_print(remaining_vertices[i], 1);
}
void
pcl::EarClipping::triangulate (const Vertices& vertices, PolygonMesh& output)
{
const int n_vertices = static_cast<const int> (vertices.vertices.size ());
if (n_vertices <= 3)
return;
std::vector<uint32_t> remaining_vertices (n_vertices);
if (area (vertices.vertices) > 0) // clockwise?
remaining_vertices = vertices.vertices;
else
for (int v = 0; v < n_vertices; v++)
remaining_vertices[v] = vertices.vertices[n_vertices - 1 - v];
// Avoid closed loops.
if (remaining_vertices.front () == remaining_vertices.back ())
remaining_vertices.erase (remaining_vertices.end () - 1);
// null_iterations avoids infinite loops if the polygon is not simple.
for (int u = static_cast<int> (remaining_vertices.size ()) - 1, null_iterations = 0;
remaining_vertices.size () > 2 && null_iterations < static_cast<int >(remaining_vertices.size () * 2);
++null_iterations, u = (u+1) % static_cast<int> (remaining_vertices.size ()))
{
int v = (u + 1) % static_cast<int> (remaining_vertices.size ());
int w = (u + 2) % static_cast<int> (remaining_vertices.size ());
if (isEar (u, v, w, remaining_vertices))
{
Vertices triangle;
triangle.vertices.resize (3);
triangle.vertices[0] = remaining_vertices[u];
triangle.vertices[1] = remaining_vertices[v];
triangle.vertices[2] = remaining_vertices[w];
output.polygons.push_back (triangle);
remaining_vertices.erase (remaining_vertices.begin () + v);
null_iterations = 0;
}
}
}
void EarClippingTriangulation::clipEars()
{
std::list<size_t>::iterator it, prev, next;
// *** clip an ear
while (_vertex_list.size() > 3)
{
// pop ear from list
size_t ear = _ear_list.front();
_ear_list.pop_front();
// remove ear tip from _convex_vertex_list
_convex_vertex_list.remove(ear);
// remove ear from vertex_list, apply changes to _ear_list, _convex_vertex_list
bool nfound(true);
it = _vertex_list.begin();
prev = _vertex_list.end();
prev--;
while (nfound && it != _vertex_list.end())
{
if (*it == ear)
{
nfound = false;
it = _vertex_list.erase(it); // remove ear tip
next = it;
if (next == _vertex_list.end())
{
next = _vertex_list.begin();
prev = _vertex_list.end();
prev--;
}
// add triangle
_triangles.push_back(GEOLIB::Triangle(_pnts, *prev, ear, *next));
// check the orientation of prevprev, prev, next
std::list<size_t>::iterator prevprev;
if (prev == _vertex_list.begin())
prevprev = _vertex_list.end();
else
prevprev = prev;
prevprev--;
// apply changes to _convex_vertex_list and _ear_list looking "backward"
MathLib::Orientation orientation = getOrientation(_pnts[*prevprev],
_pnts[*prev],
_pnts[*next]);
if (orientation == CW)
{
BASELIB::uniqueListInsert(_convex_vertex_list, *prev);
// prev is convex
if (isEar(*prevprev, *prev, *next))
// prev is an ear tip
BASELIB::uniqueListInsert(_ear_list, *prev);
else
// if necessary remove prev
_ear_list.remove(*prev);
}
else
{
// prev is not convex => reflex or collinear
_convex_vertex_list.remove(*prev);
_ear_list.remove(*prev);
if (orientation == COLLINEAR)
{
prev = _vertex_list.erase(prev);
if (prev == _vertex_list.begin())
{
prev = _vertex_list.end();
prev--;
}
else
prev--;
}
}
// check the orientation of prev, next, nextnext
std::list<size_t>::iterator nextnext,
help_it(_vertex_list.end());
help_it--;
if (next == help_it)
nextnext = _vertex_list.begin();
else
{
nextnext = next;
nextnext++;
}
// apply changes to _convex_vertex_list and _ear_list looking "forward"
orientation = getOrientation(_pnts[*prev], _pnts[*next],
_pnts[*nextnext]);
if (orientation == CW)
{
BASELIB::uniqueListInsert(_convex_vertex_list, *next);
// next is convex
if (isEar(*prev, *next, *nextnext))
// next is an ear tip
BASELIB::uniqueListInsert(_ear_list, *next);
else
// if necessary remove *next
_ear_list.remove(*next);
}
else
{
// next is not convex => reflex or collinear
_convex_vertex_list.remove(*next);
_ear_list.remove(*next);
if (orientation == COLLINEAR)
{
next = _vertex_list.erase(next);
if (next == _vertex_list.end())
next = _vertex_list.begin();
}
}
}
else
{
prev = it;
it++;
}
}
}
// add last triangle
next = _vertex_list.begin();
prev = next;
next++;
it = next;
next++;
if (getOrientation(_pnts[*prev], _pnts[*it], _pnts[*next]) == CCW)
_triangles.push_back(GEOLIB::Triangle(_pnts, *prev, *next, *it));
else
_triangles.push_back(GEOLIB::Triangle(_pnts, *prev, *it, *next));
}
Graph <Point2D> EarClipper::triangulate(const Graph <Point2D> &arg, std::vector <Triangle2D> *triangles) {
Graph <Point2D> result (arg);
std::vector<bool> vertexStatus (arg.getVertexCount(), false); //1 - ear, 0 - not ear
std::list<int> remainingVertices;
short direction = determineDirection(arg);
for (unsigned int i = 0; i < arg.getVertexCount(); ++i) {
remainingVertices.push_back(i);
}
for (std::list<int>::iterator it = remainingVertices.begin(); it != remainingVertices.end(); ++it) {
vertexStatus[*it] = isEar(arg, remainingVertices, it, direction);
}
std::list<int>::iterator currentVertex = remainingVertices.begin();
while (remainingVertices.size() > 3) {
bool earFound = false;
for (unsigned int i = remainingVertices.size(); i > 0 && remainingVertices.size() > 3; --i) {
if (vertexStatus[*currentVertex] == 1) {
earFound = true;
addTriangle(result, remainingVertices, currentVertex, triangles);
std::list<int>::iterator vertexToRemove = currentVertex;
if (++currentVertex == remainingVertices.end()) {
currentVertex = remainingVertices.begin();
}
remainingVertices.erase(vertexToRemove);
vertexStatus[*currentVertex] = isEar(arg, remainingVertices, currentVertex, direction);
if (currentVertex == remainingVertices.begin()) {
currentVertex = --remainingVertices.end();
} else {
--currentVertex;
}
vertexStatus[*currentVertex] = isEar(arg, remainingVertices, currentVertex, direction);
} else {
if (++currentVertex == remainingVertices.end()) {
currentVertex = remainingVertices.begin();
}
}
}
if (!earFound) {
result.connectVertices();
triangles->clear();
std::cerr << "Impossoble to triangulate\n";
return result;
}
}
if (triangles != 0 && remainingVertices.size() == 3) { //add remains to triangulation
triangles->push_back(Triangle2D(arg.getVertex(*remainingVertices.begin()), arg.getVertex(*++remainingVertices.begin()),
arg.getVertex(*--remainingVertices.end())));
}
if (triangles != 0) {
if (validateTriangulation(arg, *triangles)) {
std::cout << "Validation OK\n";
} else {
std::cerr << "Validation failed\n";
}
}
return result;
}
