void SHAPE_POLY_SET::importTree( PolyTree* tree)
{
m_polys.clear();
for( PolyNode* n = tree->GetFirst(); n; n = n->GetNext() )
{
if( !n->IsHole() )
{
POLYGON paths;
paths.push_back( convertFromClipper( n->Contour ) );
for( unsigned int i = 0; i < n->Childs.size(); i++ )
paths.push_back( convertFromClipper( n->Childs[i]->Contour ) );
m_polys.push_back(paths);
}
}
}
void triangulate(const Polygon& inputPoly, std::vector<Mesh>& outputMeshes)
{
// Use Clipper to ensure strictly simple polygons
using namespace ClipperLib;
Clipper clipper;
clipper.StrictlySimple(true);
try
{
clipper.AddPaths(polyToClipperPaths(inputPoly), ptSubject, true);
}
catch (...)
{
std::cerr << "Error in Clipper::AddPaths" << std::endl;
return;
}
PolyTree polyTree;
clipper.Execute(ctUnion, polyTree, pftNonZero, pftNonZero);
// Traverse the PolyTree nodes and triangulate them with only their children holes
PolyNode *currentNode = polyTree.GetFirst();
while(currentNode != NULL)
{
// The holes are only used as the children of the contours
if (currentNode->IsHole())
{
currentNode = currentNode->GetNext();
continue;
}
// Convert to poly2tri's format
std::vector<p2t::Point> allPoints;
std::vector<size_t> linesSizes;
// Contour
for (const auto& pt : currentNode->Contour)
allPoints.emplace_back(static_cast<double>(pt.X), static_cast<double>(pt.Y));
linesSizes.push_back(allPoints.size());
// Holes
for(const auto childNode : currentNode->Childs)
{
// Slightly modify the polygon to guarantee no duplicate points
edgeShrink(childNode->Contour);
for (const auto& pt : childNode->Contour)
allPoints.emplace_back(static_cast<double>(pt.X), static_cast<double>(pt.Y));
linesSizes.push_back(allPoints.size());
}
// Poly2Tri uses pointers to points
std::vector<p2t::Point*> contourLine;
std::vector<std::vector<p2t::Point*>> holes;
auto nbLines = linesSizes.size();
size_t start = 0;
for (size_t i = 0; i < nbLines; ++i)
{
size_t end = linesSizes[i];
std::vector<p2t::Point*> line;
line.reserve(end - start);
for (size_t j = start; j < end; ++j)
line.push_back(&allPoints[j]);
start = end;
if (!i) contourLine = std::move(line);
else holes.push_back(std::move(line));
}
// Set the contour in poly2tri
p2t::CDT cdt(contourLine);
// Add the holes
for(auto& hole : holes)
cdt.AddHole(hole);
// Do the actual triangulation
cdt.Triangulate();
// Downscale the points and add them to the mesh
Mesh mesh;
for (const auto pt : allPoints)
mesh.addPoint(convert(pt));
// Convert the triangles
auto triangles = cdt.GetTriangles();
auto firstPt = allPoints.data();
for (const auto triangle : triangles)
{
int ptId1 = std::distance(firstPt, triangle->GetPoint(0));
int ptId2 = std::distance(firstPt, triangle->GetPoint(1));
int ptId3 = std::distance(firstPt, triangle->GetPoint(2));
mesh.addTriangle(ptId1, ptId2, ptId3);
}
outputMeshes.push_back(mesh);
currentNode = currentNode->GetNext();
}
}
