// rayHitsObject returns whether the ray intersects one object in the scene.
func (s *Scene) rayHitsObject(ray geom.Line) bool {
for i := range s.Objects {
_, _, ok := geom.SphereLineIntersection(s.Objects[i].Sphere, ray)
if ok {
return true
}
}
return false
}
// castRay finds the nearest intersection point between the ray and the scene
// objects. On return, obj is nil if there is no intersection.
func (s *Scene) castRay(ray geom.Line) (obj *Sphere, intersection geom.Point) {
var pmin geom.Point
tmin := math.MaxFloat64
imin := -1
for i := range s.Objects {
p, t, ok := geom.SphereLineIntersection(s.Objects[i].Sphere, ray)
if ok {
if t < tmin {
tmin = t
pmin = p
imin = i
}
}
}
if imin == -1 {
return nil, geom.Origin
}
return &s.Objects[imin], pmin
}