🐆 camera focus distance

Author: michalbe

src/camera.rs

@@ -1,15 +1,31 @@
 use crate::ray::Ray;
 use vec3D::Vec3D;
 
+fn random_in_unit_disk() -> Vec3D {
+    let mut p: Vec3D;
+
+    loop {
+        p = Vec3D::new(rand::random::<f64>(), rand::random::<f64>(), 0.0) * 2.0 - Vec3D::new(1.0, 1.0, 0.0);
+
+        if p.dot(p) < 1.0 {
+            break;
+        }
+    }
+    p
+}
+
 pub struct Camera {
     pub origin: Vec3D,
     pub lower_left_corner: Vec3D,
     pub horizontal: Vec3D,
     pub vertical: Vec3D,
+    pub lens_radius: f64,
+    u: Vec3D,
+    v: Vec3D,
 }
 
 impl Camera {
-    pub fn new(look_from: Vec3D, look_at: Vec3D, up: Vec3D, vfov: f64, aspect: f64) -> Camera {
+    pub fn new(look_from: Vec3D, look_at: Vec3D, up: Vec3D, vfov: f64, aspect: f64, aperture: f64, focus_distance: f64) -> Camera {
         let theta = vfov * std::f64::consts::PI / 180.0;
         let half_height = (theta / 2.0).tan();
         let half_width = aspect * half_height;
@@ -20,14 +36,19 @@ impl Camera {
         let origin = look_from;
 
         Camera {
-            lower_left_corner: origin - u * half_width - v * half_height - w,
-            horizontal: u * half_width * 2.0,
-            vertical: v * half_height * 2.0,
+            lower_left_corner: origin - u * focus_distance * half_width - v * focus_distance * half_height - w * focus_distance,
+            horizontal: u * half_width * 2.0 * focus_distance,
+            vertical: v * half_height * 2.0 * focus_distance,
             origin,
+            lens_radius: aperture / 2.0,
+            u,
+            v,
         }
     }
 
-    pub fn get_ray(&self, u: f64, v: f64) -> Ray {
-        Ray::new(self.origin, self.lower_left_corner + (self.horizontal * u) + (self.vertical * v) - self.origin)
+    pub fn get_ray(&self, s: f64, t: f64) -> Ray {
+        let rd = random_in_unit_disk() * self.lens_radius;
+        let offset = self.u * rd.x + self.v * rd.y;
+        Ray::new(self.origin + offset, self.lower_left_corner + (self.horizontal * s) + (self.vertical * t) - self.origin - offset)
     }
 }

src/main.rs

@@ -50,7 +50,20 @@ fn main() {
         Material::Dielectric(Dielectric::new(1.5))
     )));
 
-    let camera = Camera::new(120.0, nx as f64 / ny as f64);
+    let look_from = Vec3D::new(3.0, 3.0, 2.0);
+    let look_at = Vec3D::new(0.0, 0.0, -1.0);
+    let distance_to_focus = (look_from - look_at).mag();
+    let aperture = 2.0;
+
+    let camera = Camera::new(
+        look_from,
+        look_at,
+        Vec3D::new(0.0, 1.0, 0.0),
+        20.0,
+        nx as f64 / ny as f64,
+        aperture,
+        distance_to_focus
+    );
 
     for j in (0..ny).rev() {
         for i in 0..nx {