latest update

src/material.rs

@@ -1,13 +1,30 @@
 use crate::hittable::HitRecord;
-use crate::ray::Ray;
-use crate::rtweekend::*;
-use crate::hittable_list::*;
-use crate::vec3::Color;
+use crate::ray::{Ray, self};
+use crate::vec3::{Color, random_unit_vector};
 
 pub struct Material {
 
 }
 
 trait Scatter {
-    fn scatter(r_in: &Ray, rec: HitRecord, attenuation: &Color, scattered: &Ray) -> bool;
+    fn scatter(&self, r_in: &Ray, rec: HitRecord, attenuation: &mut Color, scattered: &mut Ray) -> bool;
+}
+
+pub struct Lambertian {
+    albedo: Color,
+}
+
+impl Lambertian {
+    pub fn new(a: &Color) -> Self {
+        Lambertian { albedo: *a }
+    }
+}
+
+impl Scatter for Lambertian {
+    fn scatter(&self, r_in: &Ray, rec: HitRecord, attenuation: &mut Color, scattered: &mut Ray) -> bool {
+        let scatter_direction = rec.normal + random_unit_vector();
+        scattered = &mut Ray::new(rec.p, scatter_direction);
+        attenuation = &mut self.albedo;
+        return true;
+    }
 }