/*
Simplificate a mesh using CGALs Triangulated Surface Mesh Simplification
(http://doc.cgal.org/latest/Surface_mesh_simplification/index.html#Chapter_Triangulated_Surface_Mesh_Simplification)
*/
const char* CGALSimplificateSurface(const char* inputMeshFile,
const char* outputMeshFile,
int stopnr,
std::vector<double> box = std::vector<double>()) {
vtkSmartPointer<vtkPolyData> inputPoly = IOHelper::VTKReadPolyData(inputMeshFile);
Polyhedron polyhedron;
VTKPolydataToCGALPolyhedron_converter(inputPoly, &polyhedron);
//create stop predicate
CGAL::Surface_mesh_simplification::Count_stop_predicate<Polyhedron> stop(stopnr);
Constrains_map constrains_map ;
//if box contains exactly six values, use region inside box to mark non-removable edges
if(box.size()==6)
{
int totalEdges=0;
int constrainedEdges=0;
log_debug()<<"bounding box given"<<std::endl;
//iterate over all edges, edges inside box will be marked as non-removable
for(Polyhedron::Halfedge_iterator eb = polyhedron.halfedges_begin(),
ee = polyhedron.halfedges_end() ; eb != ee ; ++ eb )
{
Point currentPoint = eb->vertex()->point();
//test if edge vertex is within box
if( (currentPoint[0]>=box[0]) && (currentPoint[1]>=box[1]) && (currentPoint[2]>=box[2])
&& (currentPoint[0]<=box[3]) && (currentPoint[1]<=box[4]) && (currentPoint[2]<=box[5]))
{ //add to map of non-removable edges
constrains_map.set_is_constrained(eb,true);
constrainedEdges++;
}
totalEdges++;
}
log_debug()<<"total edges: "<<totalEdges<<" constrained: "<<constrainedEdges<<std::endl;
}
//simplificate mesh
int r = CGAL::Surface_mesh_simplification::edge_collapse
(polyhedron,stop,
CGAL::vertex_index_map(boost::get(CGAL::vertex_external_index,polyhedron))
.edge_index_map (boost::get(CGAL::edge_external_index ,polyhedron))
.edge_is_border_map(constrains_map)
);
log_debug()<<"Edges removed: "<<r<<std::endl;
//now create polydata-object
vtkSmartPointer<vtkPolyData> vtkpoly = vtkSmartPointer<vtkPolyData>::New();
//convert polyhedron to polydata
CGALPolyhedronToVTKPolydata_converter(&polyhedron, vtkpoly);
//write polydata to disk
bool result = IOHelper::VTKWritePolyData(outputMeshFile,vtkpoly);
return outputMeshFile;
}
void mergeColinear(Polyhedron& p) {
int vertBefore = p.size_of_vertices();
bool colinearFound = true;
while (colinearFound) {
colinearFound = false; // Set temporarily to false, if merge degments then set true
int percCount = 1;
for (Polyhedron::Halfedge_iterator hit = p.halfedges_begin(); hit != p.halfedges_end(); ++hit,++percCount){
if (CGAL::circulator_size(hit->vertex_begin()) == 1) {
std::cerr << "WARNING: Loose edge, but how??"<<std::endl;
while (CGAL::circulator_size(hit->vertex_begin()) == 1)
hit = p.join_vertex(hit->opposite());
break;
}
if ((CGAL::circulator_size(hit->vertex_begin()) == 2) && // if only two he connected to vertex
(hit->facet_degree()>3 && hit->opposite()->facet_degree()>3)) { // if faces are not triangles // prob faster
Vector_3 cur(hit->prev()->vertex()->point(),hit->vertex()->point());
Vector_3 nex(hit->vertex()->point(),hit->next()->vertex()->point());
if ( is_colinear(cur,nex)) { // check if colinear
std::cout << "\rVertices before/after: "<<vertBefore<<" -> "<< p.size_of_vertices()<<". ("<<100*percCount/p.size_of_halfedges()<<"%)";
p.join_vertex(hit->opposite()); // move cur to prev point
colinearFound = true;
break;
} } } }
std::cout << "\rVertices before/after: "<<vertBefore<<" -> "<< p.size_of_vertices()<<". (100%)" << std::endl;
}
