// Shade returns the emitted colour after intersecting the material
func (m *RefractiveMaterial) Shade(intersection *ray.Intersection, raytracer Raytracer) *hdrcolour.Colour {
incoming := &intersection.Incoming.Direction
normal := intersection.Normal
ior := m.IOR.GetFac(intersection)
colour := m.Colour.GetColour(intersection)
refracted := &maths.Vec3{}
startPoint := &maths.Vec3{}
if maths.DotProduct(incoming, normal) < 0 {
refracted = maths.Refract(incoming, normal, 1/ior)
} else {
refracted = maths.Refract(incoming, normal.Negative(), ior)
}
if refracted != nil {
// regular refraction - push the starting point a tiny bit
// through the surface
startPoint = maths.MinusVectors(
intersection.Point, normal.FaceForward(incoming).Scaled(maths.Epsilon),
)
} else {
// total inner reflection
refracted = incoming.Reflected(normal.FaceForward(incoming))
// push the starting point a tiny bit away from the surface
startPoint = maths.AddVectors(
intersection.Point, normal.FaceForward(incoming).Scaled(maths.Epsilon),
)
}
newRay := &ray.Ray{Depth: intersection.Incoming.Depth + 1}
newRay.Start = *startPoint
newRay.Direction = *refracted
return hdrcolour.MultiplyColours(raytracer.Raytrace(newRay), colour)
}
// Shade returns the emitted colour after intersecting the material
func (m *ReflectiveMaterial) Shade(intersection *ray.Intersection, raytracer Raytracer) *hdrcolour.Colour {
incoming := intersection.Incoming
colour := m.Colour.GetColour(intersection)
reflectedRay := &ray.Ray{Depth: incoming.Depth + 1}
reflectedRay.Direction = *incoming.Direction.Reflected(intersection.Normal)
reflectedRay.Start = *maths.AddVectors(intersection.Point, intersection.Normal.Scaled(maths.Epsilon))
return hdrcolour.MultiplyColours(raytracer.Raytrace(reflectedRay), colour)
}