ft: 10: metals

src/objects/materials/lambertian.rs

@@ -0,0 +1,79 @@
+use rand::RngExt;
+
+use crate::{
+    objects::{hit::Hit, materials::traits::Material},
+    ray::Ray,
+    vec3::{Colour, Vec3},
+};
+
+pub struct Lambertian {
+    albedo: Colour,
+    prob: f32,
+}
+
+impl Lambertian {
+    pub fn new(albedo: Colour, prob: f32) -> Self {
+        Self {
+            albedo: albedo,
+            prob: prob,
+        }
+    }
+
+    pub fn rgb(r: f32, g: f32, b: f32, prob: f32) -> Self {
+        Self {
+            albedo: Colour::new(r, g, b),
+            prob: prob,
+        }
+    }
+}
+
+impl Material for Lambertian {
+    fn scatter(&self, hit: &Hit, ray: &Ray) -> Option<(Ray, Colour)> {
+        let mut rng = rand::rng();
+        if self.prob >= rng.random::<f32>() {
+            let mut dir = *hit.n() + Vec3::random_unit();
+            if dir.near_zero() {
+                dir = *hit.n();
+            }
+            let scattered = Ray::new(*hit.p(), dir);
+            return Some((scattered, self.albedo));
+        }
+        return None;
+    }
+}
+
+pub struct Metal {
+    albedo: Colour,
+    prob: f32,
+    fuzz: f32,
+}
+
+impl Metal {
+    pub fn new(albedo: Colour, prob: f32, fuzz: f32) -> Self {
+        Self {
+            albedo: albedo,
+            prob: prob,
+            fuzz: fuzz,
+        }
+    }
+
+    pub fn rgb(r: f32, g: f32, b: f32, prob: f32, fuzz: f32) -> Self {
+        Self {
+            albedo: Colour::new(r, g, b),
+            prob: prob,
+            fuzz: fuzz,
+        }
+    }
+}
+
+impl Material for Metal {
+    fn scatter(&self, hit: &Hit, ray: &Ray) -> Option<(Ray, Colour)> {
+        let mut rng = rand::rng();
+        if self.prob >= rng.random::<f32>() {
+            let mut refl = ray.dir().reflect(hit.n());
+            refl = refl.get_unit() + self.fuzz * Vec3::random_unit();
+            return Some((Ray::new(*hit.p(), refl), self.albedo));
+        }
+        return None;
+    }
+}