Chapter 10

1 files changed, 6 insertions, 2 deletions

diff --git a/ray.go b/ray.go
index 18c8a39..2d7f29c 100644
--- a/ray.go
+++ b/ray.go
@@ -7,6 +7,7 @@ import (
 type Ray struct {
   Origin Vec3
   Direction Vec3
+  Valid bool
 }
 
 func (r Ray) At(t float64) Vec3 {
@@ -20,8 +21,11 @@ func (r Ray) Colour(world Hittable, md uint) Vec3 {
 
   hit := world.Hit(r, Interval{0.001, maths.Inf(1)})
   if hit.Valid {
-    dir := hit.N.Add(RandomVec3OnUnitSphere());
-    return Ray{hit.P, dir}.Colour(world, md - 1).Div(SplatVec3(10));
+    scat := hit.Mat.Scatter(r, hit);
+    if scat.Valid {
+      return scat.Colour(world, md - 1).Mul(hit.Mat.Attenuation());
+    }
+    return SplatVec3(0);
   }
 
   unit_dir := r.Direction.Unit();