func (s *segment) shiftBy(v vector.V2) *segment { dprintf("shifting by %v", v) s.from = Vertex2(vector.V2(s.from).Add(v)) s.to = Vertex2(vector.V2(s.to).Add(v)) s.line = nil return s }
func (v1 Vertex2) distFrom(v2 Vertex2) float64 { v := vector.V2(v2).Sub(vector.V2(v1)) return v.Length() }