void addPolygon( const TIntVector& ib )
{
++polygonCount;
TIntVector::const_iterator vit, vitEnd = ib.end();
for( vit = ib.begin(); vit != vitEnd; ++vit ) {
int idx = *vit;
assert( idx >= 0 && idx < vertexUseCount.size() );
vertices.insert( idx );
++vertexUseCount[idx];
int idxNext = (vit==vitEnd-1) ? ib.front() : *(vit+1);
int idxPrev = (vit==ib.begin()) ? ib.back() : *(vit-1);
vertexNexts[idx].push_back( idxNext );
vertexPrevs[idx].push_back( idxPrev );
}
}
