ft: 13: optional defocus blur

src/vec3.rs

@@ -17,8 +17,8 @@ pub struct Vec3 {
 pub type Colour = Vec3;
 
 impl Vec3 {
-    pub fn new(r: f32, g: f32, b: f32) -> Self {
-        Self { x: r, y: g, z: b }
+    pub fn new(x: f32, y: f32, z: f32) -> Self {
+        Self { x, y, z }
     }
 
     pub fn nil() -> Self {
@@ -47,6 +47,16 @@ impl Vec3 {
         }
     }
 
+    pub fn random_in_unit_disk() -> Self {
+        loop {
+            let mut p = Vec3::random();
+            p.z = 0.;
+            if p.length_squared() < 1. {
+                return p;
+            }
+        }
+    }
+
     pub fn random_unit_hemisphere(n: &Self) -> Self {
         let v = Self::random_unit();
         if n.dot(&v) > 0.0 {
@@ -340,6 +350,19 @@ impl Mul<&Vec3> for f32 {
     }
 }
 
+impl Mul<Vec3> for &f32 {
+    type Output = Vec3;
+
+    fn mul(self, rhs: Vec3) -> Self::Output {
+        Vec3 {
+            x: rhs.x * self,
+            y: rhs.y * self,
+            z: rhs.z * self,
+        }
+    }
+
+}
+
 impl MulAssign<Vec3> for Vec3 {
     fn mul_assign(&mut self, rhs: Self) {
         *self = Self {