sphere.go

package main

import "math"

func main() {

	s := Sphere{center: Point{0, 0, 0}, radius: 1}
	p := Point{0.1, 0.1, 0.1}
	println(s.contains(p))

}

type Point struct {
	x, y, z float64
}

func (p *Point) distance_from_origin() float64 {
	return p.distance_to(Point{0, 0, 0})
}

func (p *Point) distance_to(p2 Point) float64 {
	return math.Sqrt(math.Pow(p2.x-p.x, 2) + math.Pow(p2.y-p.y, 2) + math.Pow(p2.z-p.z, 2))
}

type Sphere struct {
	center Point
	radius float64
}

func (s *Sphere) volume() float64 {
	return 4.0 / 3.0 * math.Pi * math.Pow(s.radius, 3)
}

func (s *Sphere) contains(p Point) bool {
	return p.distance_to(s.center) < s.radius
}