replaceVertex method
Implementation
void replaceVertex(Vertex oldv, Vertex newv ) {
if ( oldv == v1 ){
v1 = newv;
}
else if ( oldv == v2 ){
v2 = newv;
}
else if ( oldv == v3 ){
v3 = newv;
}
SimplifyModifier._removeFromArray( oldv.faces, this );
newv.faces.add( this );
oldv.removeIfNonNeighbor(v1! );
v1?.removeIfNonNeighbor( oldv );
oldv.removeIfNonNeighbor(v2! );
v2?.removeIfNonNeighbor( oldv );
oldv.removeIfNonNeighbor( v3! );
v3?.removeIfNonNeighbor( oldv );
v1?.addUniqueNeighbor( v2 );
v1?.addUniqueNeighbor( v3 );
v2?.addUniqueNeighbor( v1 );
v2?.addUniqueNeighbor( v3 );
v3?.addUniqueNeighbor( v1 );
v3?.addUniqueNeighbor( v2 );
computeNormal();
}