coplanar method
Returns true if the polygon is coplanar.
Implementation
bool coplanar([double epsilon = 1e-3 ]) {
final plane = this.plane;
HalfEdge? edge = this.edge;
do{
final distance = plane.distanceToPoint( edge!.vertex );
if ( distance.abs() > epsilon ) {
return false;
}
edge = edge.next;
} while ( edge != this.edge );
return true;
}