Positional camera

.gitignore

@@ -2,3 +2,4 @@
 *.ppm
 .idea
 *.iml
+.vscode/

src/camera.rs

@@ -4,42 +4,56 @@ pub struct Camera {
     aspect_ratio: f64,
     viewport_height: f64,
     viewport_width: f64,
-    focal_length: f64,
     origin: Point3,
     horizontal: Vec3,
     vertical: Vec3,
-    lower_left_corner: Vec3
+    lower_left_corner: Vec3,
+    lens_radius: f64,
+    u: Vec3,
+    v: Vec3,
+    w: Vec3
 }
 
 impl Camera {
-    pub fn get_ray(&self, u: f64, v: f64) -> Ray {
+    pub fn get_ray(&self, s: f64, t: f64) -> Ray {
+        let rd = self.lens_radius * Vec3::random_unit_disk();
+        let offset = self.u * rd.x() + self.v * rd.y();
         Ray::new(
-            self.origin,
-            self.lower_left_corner + u*self.horizontal + v*self.vertical - self.origin)
+            self.origin + offset,
+            self.lower_left_corner + s*self.horizontal + t*self.vertical - self.origin - offset)
     }
-    pub fn new(aspect_ratio: f64) -> Self {
-        let viewport_height = 2.0;
+    pub fn new(
+        look_from: Point3,
+        look_at: Point3,
+        up: Vec3,
+        aspect_ratio: f64,
+        vfov: f64,
+        aperture: f64,
+        focus_dist: f64) -> Self {
+
+        let theta = vfov.to_radians();
+        let h = (theta / 2.0).tan();
+        let viewport_height = 2.0 * h;
         let viewport_width = aspect_ratio * viewport_height;
-        let origin = Point3::default();
-        let horizontal = Vec3::new(viewport_width, 0.0, 0.0);
-        let vertical = Vec3::new(0.0, viewport_height, 0.0);
-        let focal_length = 1.0;
+
+        let w = (look_from - look_at).unit_vector();
+        let u = up.cross(&w).unit_vector();
+        let v = w.cross(&u);
+
+        let horizontal = focus_dist * viewport_width * u;
+        let vertical = focus_dist * viewport_height * v;
         Camera {
             aspect_ratio,
             viewport_height,
             viewport_width,
-            focal_length,
-            origin,
+            origin: look_from,
             horizontal,
             vertical,
-            lower_left_corner: origin - horizontal/2.0 - vertical/2.0 - Vec3::new(0.0, 0.0, focal_length)
+            lower_left_corner: look_from - horizontal/2.0 - vertical/2.0 - focus_dist*w,
+            lens_radius: aperture / 2.0,
+            u,
+            v,
+            w
         }
     }
 }
-
-impl Default for Camera {
-    fn default() -> Self {
-        let aspect_ratio = 16.0 / 9.0;
-        Camera::new(aspect_ratio)
-    }
-}

src/hittable.rs

@@ -42,16 +42,16 @@ impl Hittable for Sphere {
         let discriminant = half_b * half_b - a * c;
         if discriminant < 0.0 { return None; }
 
-        let sqrtd = f64::sqrt(discriminant);
-        let root = (-half_b - sqrtd) / a;
+        let sqrtd = discriminant.sqrt();
+        let mut root = (-half_b - sqrtd) / a;
         if root < t_min || t_max < root {
-            let root = (-half_b + sqrtd) / a;
+            root = (-half_b + sqrtd) / a;
             if root < t_min || t_max < root { return None; }
         }
-
         let point = ray.at(root);
         let normal = (point - self.center) / self.radius;
-        let front_face = ray.direction().dot(&normal) < 0.0;
+        let dot = ray.direction().dot(&normal);
+        let front_face = dot < 0.0;
         let normal = if front_face { normal } else { -normal };
         Some(HitRecord {
             point,

src/main.rs

@@ -8,59 +8,79 @@ use crate::material::{Dielectric, Lambertian, Material, Metal};
 mod vec3;
 mod ray;
 mod hittable;
-mod camera;
 mod material;
+mod camera;
+
+fn random_scene() -> Vec<Box<dyn Hittable>> {
+    let mut world:Vec<Box<dyn Hittable>> = Vec::new();
+
+    let material_ground = Material::Lambertian(Lambertian::new(Color::new(0.5, 0.5, 0.5)));
+    let ground = Sphere {
+        center: Point3::new(0.0, -1000.0, 0.0),
+        radius: 1000.0,
+        material: material_ground
+    };
+    world.push(Box::new(ground));
+
+    let unit_range = Uniform::from(0.0..1.0);
+    let fuzz_range = Uniform::from(0.0..0.5);
+    let mut rng = rand::thread_rng();
+    let p = Point3::new(4.0, 0.2, 0.0);
+    for a in -1..11 {
+        for b in -11..11 {
+            let choose_material = unit_range.sample(&mut rng);
+            let center = Point3::new(
+                (a as f64) + 0.9*unit_range.sample(&mut rng),
+                0.2,
+                (b as f64) + 0.9*unit_range.sample(&mut rng));
+            if (center - p).length() < 0.9 {
+                continue;
+            }
+            let material = match choose_material {
+                _ if choose_material < 0.8 => Material::Lambertian(Lambertian::new(
+                    Color::random(0.0, 1.0) * Color::random(0.0, 1.0))),
+                _ if choose_material < 0.95 => Material::Metal(Metal::new(
+                    Color::random(0.5, 1.0),
+                    fuzz_range.sample(&mut rng))),
+                _ => Material::Dielectric(Dielectric::new(1.5)),
+            };
+            let sphere = Box::new(Sphere {
+                center,
+                radius: 0.2,
+                material
+            });
+            world.push(sphere);
+        }
+    }
+    world
+}
 
 fn main() {
     // Image
-    const ASPECT_RATIO: f64 = 16.0 / 9.0;
-    const IMAGE_WIDTH: i32 = 400;
+    const ASPECT_RATIO: f64 = 3.0 / 2.0;
+    const IMAGE_WIDTH: i32 = 1200;
     const IMAGE_HEIGHT: i32 = (IMAGE_WIDTH as f64 / ASPECT_RATIO) as i32;
     const SAMPLES_PER_PIXEL: i32 = 10;
     const MAX_DEPTH: i32 = 50;
 
+    let look_from = Point3::new(13.0, 2.0, 3.0);
+    let look_at = Point3::new(0.0, 0.0, 0.0);
+    let focus_dist = 10.0;
     // Camera
-    let cam = Camera::new(ASPECT_RATIO);
+    let cam = Camera::new(
+        look_from,
+        look_at,
+        Vec3::new(0.0, 1.0, 0.0),
+        ASPECT_RATIO,
+        20.0,
+        0.1,
+        focus_dist);
 
     // World
-    let mut world:Vec<Box<dyn Hittable>> = Vec::new();
-
-    let center = Box::new(Sphere {
-        center: Point3::new(0.0, 0.0, -1.0),
-        radius: 0.5,
-        material: Material::Lambertian(Lambertian::new(Color::new(0.7, 0.3, 0.3)))
-    });
-    let center_glass = Box::new(Sphere {
-        center: Point3::new(0.0, 0.0, -1.0),
-        radius: 0.5,
-        material: Material::Dielectric(Dielectric::new(1.5))
-    });
-    world.push(center_glass);
-    let ground = Sphere {
-        center: Point3::new(0.0, -100.5, -1.0),
-        radius: 100.0,
-        material: Material::Lambertian(Lambertian::new(Color::new(0.8, 0.8, 0.0)))
-    };
-    world.push(Box::new(ground));
-    let left = Box::new(Sphere {
-        center: Point3::new(-1.0, 0.0, -1.0),
-        radius: 0.5,
-        material: Material::Metal(Metal::new(Color::new(0.8, 0.8, 0.8), 0.3))
-    });
-    let left_glass = Box::new(Sphere {
-        center: Point3::new(-1.0, 0.0, -1.0),
-        radius: 0.5,
-        material: Material::Dielectric(Dielectric::new(1.5))
-    });
-    world.push(left_glass);
-    let right = Box::new(Sphere {
-        center: Point3::new(1.0, 0.0, -1.0),
-        radius: 0.5,
-        material: Material::Metal(Metal::new(Color::new(0.8, 0.6, 0.2), 1.0))
-    });
-    world.push(right);
+    let world= random_scene();
 
     println!("P3\n{} {}\n255", IMAGE_WIDTH, IMAGE_HEIGHT);
+
     let between = Uniform::from(0.0..1.0);
     let mut rng = rand::thread_rng();
     for j in (0..IMAGE_HEIGHT).rev() {
@@ -72,6 +92,9 @@ fn main() {
                 let u = (i as f64 + random_number) / (IMAGE_WIDTH - 1) as f64;
                 let v = (j as f64 + random_number) / (IMAGE_HEIGHT - 1) as f64;
                 let ray = cam.get_ray(u, v);
+                if i == 200 && (j == 112 || j == 113) {
+                    let tt = 0;
+                }
                 color += ray.pixel_color(&world, MAX_DEPTH);
             }
             color.write_color(SAMPLES_PER_PIXEL);

src/material.rs

@@ -104,6 +104,7 @@ impl Scatterable for Dielectric {
             self.index_of_refraction
         };
         let unit_direction = ray.direction().unit_vector();
+
         let cos_theta = ((-unit_direction).dot(&hit_record.normal)).min(1.0);
         let sin_theta = (1.0 - cos_theta*cos_theta).sqrt();
         let cannot_refract = refraction_ratio * sin_theta > 1.0;
@@ -112,12 +113,10 @@ impl Scatterable for Dielectric {
 
         if cannot_refract || reflectance > rng.gen::<f64>() {
             let reflected = unit_direction.reflected(&hit_record.normal);
-            let reflected = Vec3::new(-reflected.x(), reflected.y(), -reflected.z());
             let scattered = Ray::new(hit_record.point, reflected);
             Some((Some(scattered), color))
         } else {
-            //let direction = unit_direction.refract(&hit_record.normal, refraction_ratio);
-            let direction = unit_direction.refract_sort_of_works(&hit_record.normal, refraction_ratio);
+            let direction = unit_direction.refract(&hit_record.normal, refraction_ratio);
             let scattered = Ray::new(hit_record.point, direction);
             Some((Some(scattered), color))
         }

src/ray.rs

@@ -3,6 +3,7 @@ use crate::hittable::HitRecord;
 use crate::material::Scatterable;
 use crate::vec3::Point3;
 
+#[derive(Debug)]
 pub struct Ray {
     origin: Point3,
     direction: Vec3

src/vec3.rs

@@ -63,6 +63,19 @@ impl Vec3 {
         }
     }
     pub fn random_unit_vector() -> Self { Vec3::random_in_unit_sphere().unit_vector() }
+    pub fn random_unit_disk() -> Self {
+        let between = Uniform::from(-1.0..1.0);
+        let mut rng = rand::thread_rng();
+        loop {
+            let v = Vec3::new(
+                between.sample(&mut rng),
+                between.sample(&mut rng),
+                0.0);
+            if v.length_squared() < 1.0 {
+                return v;
+            }
+        }
+    }
     pub fn near_zero(&self) -> bool {
         const MAXIMUM_DISTANCE_FROM_ZERO:f64 = 1e-8;
         self.x.abs() < MAXIMUM_DISTANCE_FROM_ZERO &&
@@ -84,21 +97,6 @@ impl Vec3 {
         let out_parallel = r * (*normal);
         out_perp + out_parallel
     }
-    pub fn refract_sort_of_works(&self, normal: &Vec3, etai_over_etat: f64) -> Vec3 {
-        let dot = (-(*self)).dot(normal);
-        let cos_theta = dot.min(1.0);
-        let out_perp = etai_over_etat * ((*self) + cos_theta * (*normal));
-        let inner =  1.0 - out_perp.length_squared();
-        let abs = inner.abs();
-        let r = -(abs.sqrt());
-        let out_parallel = r * (*normal);
-        // Why?
-        let mut res = out_perp + out_parallel;
-        res.x = -res.x;
-        //res.y = -res.y;
-        res.z = -res.z;
-        res
-    }
 }
 
 #[test]