// ------------------------------------------------------------------------------------------------
void TempMesh::RemoveDegenerates()
{
// The strategy is simple: walk the mesh and compute normals using
// Newell's algorithm. The length of the normals gives the area
// of the polygons, which is close to zero for lines.
std::vector<IfcVector3> normals;
ComputePolygonNormals(normals, false);
bool drop = false;
size_t inor = 0;
std::vector<IfcVector3>::iterator vit = verts.begin();
for (std::vector<unsigned int>::iterator it = vertcnt.begin(); it != vertcnt.end(); ++inor) {
const unsigned int pcount = *it;
if (normals[inor].SquareLength() < 1e-10f) {
it = vertcnt.erase(it);
vit = verts.erase(vit, vit + pcount);
drop = true;
continue;
}
vit += pcount;
++it;
}
if(drop) {
IFCImporter::LogDebug("removing degenerate faces");
}
}
// ------------------------------------------------------------------------------------------------
void TempMesh::FixupFaceOrientation()
{
const IfcVector3 vavg = Center();
std::vector<IfcVector3> normals;
ComputePolygonNormals(normals);
size_t c = 0, ofs = 0;
BOOST_FOREACH(unsigned int cnt, vertcnt) {
if (cnt>2){
const IfcVector3& thisvert = verts[c];
if (normals[ofs]*(thisvert-vavg) < 0) {
std::reverse(verts.begin()+c,verts.begin()+cnt+c);
}
}
c += cnt;
++ofs;
}
}
