func (v Vec2) Dist(v1 Vec2) float32 {
	dx := v1[0] - v[0]
	dy := v1[1] - v[1]
	return math32.Sqrt(dx*dx + dy*dy)
}
func (v Vec2) Dist(v1 Vec2) float32 {
	dx := v1[0] - v[0]
	dy := v1[1] - v[1]
	return math32.Sqrt(dx*dx + dy*dy)
}
// Dist returns the distance between v and v1. d = dist(v, v2)