added metals and dielectrics

src/vec3.rs

@@ -1,4 +1,4 @@
-use std::ops::{Add, Sub, AddAssign, SubAssign, Mul, Div, MulAssign, DivAssign, Neg};
+use std::{ops::{Add, Sub, AddAssign, SubAssign, Mul, Div, MulAssign, DivAssign, Neg}};
 
 use crate::rtweekend::{random_f64, random_range_f64};
 
@@ -8,7 +8,7 @@ pub struct Vec3 {
 }
 
 impl Vec3 {
-    pub fn new(x: f64, y: f64, z: f64) -> Self {
+    pub const fn new(x: f64, y: f64, z: f64) -> Self {
         Vec3 { elements: [x, y, z] }
     }
 
@@ -126,6 +126,20 @@ impl Mul<f64> for Vec3 {
     }
 }
 
+impl Mul<Self> for Vec3 {
+    type Output = Self;
+
+    fn mul(self, rhs: Self) -> Self::Output {
+        Self {
+            elements: [
+                self.x() * rhs.x(),
+                self.y() * rhs.y(),
+                self.z() * rhs.z()
+            ]
+        }
+    }
+}
+
 impl Mul<Vec3> for f64 {
     type Output = Vec3;
 
@@ -225,4 +239,12 @@ pub fn random_in_hemisphere(normal: &Vec3) -> Vec3 {
 
 pub fn reflect(v: &Vec3, n: &Vec3) -> Vec3 {
     *v - 2.0 * v.dot(n) * *n
+}
+
+pub fn refract(uv: &Vec3, n: &Vec3, etai_over_etat: f64) -> Vec3 {
+    let cos_theta = f64::min(-uv.dot(&n), 1.0);
+    let r_out_perp = etai_over_etat * (*uv + cos_theta * *n);
+    let r_out_parallel = -f64::sqrt(f64::abs(1.0 - r_out_perp.length_squared())) * *n;
+    
+    r_out_perp + r_out_parallel
 }