Add reflecting material

2 files changed, 41 insertions, 0 deletions

diff --git a/src/material/mod.rs b/src/material/mod.rs
index 62cbf9a..c939385 100644
--- a/src/material/mod.rs
+++ b/src/material/mod.rs
@@ -2,8 +2,10 @@ use crate::core::{Ray, Intersection, Spectrum};
 use crate::sample::Sampler;
 
 mod lambertian;
+mod reflectant;
 
 pub use lambertian::Lambertian;
+pub use reflectant::Reflectant;
 
 pub trait Material {
     fn scatter(&self, ray: &Ray, i: &Intersection, sampler: &mut dyn Sampler) -> Option<(Spectrum, Ray)>;
diff --git a/src/material/reflectant.rs b/src/material/reflectant.rs
new file mode 100644
index 0000000..f4b110c
--- /dev/null
+++ b/src/material/reflectant.rs
@@ -0,0 +1,39 @@
+use crate::Float;
+use crate::core::{Ray, Intersection, Spectrum, Vector3f};
+use super::Material;
+use crate::sample::Sampler;
+
+pub struct Reflectant {
+    color: Spectrum,
+    fuzz: Option<Float>,
+}
+
+impl Reflectant {
+    pub fn new(c: Spectrum, fuzz: Option<Float>) -> Reflectant {
+        Reflectant {
+            color: c,
+            fuzz,
+        }
+    }
+}
+
+fn reflect(v: &Vector3f, n: &Vector3f) -> Vector3f {
+    *v - *n * (2.0 * v.dot(n))
+}
+
+impl Material for Reflectant {
+    fn scatter(&self, ray: &Ray, i: &Intersection, sampler: &mut dyn Sampler) -> Option<(Spectrum, Ray)> {
+        // Find reflectance vector
+        let mut reflected = reflect(&ray.direction, &i.n);
+        if let Some(fuzz) = self.fuzz {
+            reflected += &(sampler.get_unit_vector() * fuzz);
+        }
+
+        Some((
+                self.color,
+                Ray::new(i.p, reflected.norm()),
+                ))
+    }
+}
+
+