Feat: Camera positioning

The camera can now be fully described in 3D space. Close of Chapter 11.

src/camera.rs

@@ -22,30 +22,33 @@ pub struct Camera {
 }
 
 impl Camera {
-    pub fn new(vfov: f32, aspect_ratio: f32) -> Camera {
+    pub fn new(lookfrom: Vec3, lookat: Vec3, vup: Vec3, vfov: f32, aspect_ratio: f32) -> Camera {
         let theta = degrees_to_radians(vfov);
         let h = (theta / 2.0).tan();
         let vp_height = 2.0 * h;
         let vp_width = aspect_ratio * vp_height;
 
-        let focal_length = 1.0;
+        let w = Vec3::as_unit(lookfrom - lookat);
+        let u = Vec3::as_unit(Vec3::cross(vup, w));
+        let v = Vec3::cross(w, u);
 
-        let horiz = Vec3::new(vp_width, 0.0, 0.0);
-        let verti = Vec3::new(0.0, vp_height, 0.0);
-        let orig = Vec3::zero();
+        let orig = lookfrom;
+        let horiz = u * vp_width;
+        let verti = v * vp_height;
+        let lower_left_corner = orig - horiz / 2.0 - verti / 2.0 - w;
 
         Camera{
             origin: orig,
-            lower_left_corner: orig - horiz/2.0 - verti/2.0 - Vec3::new(0.0, 0.0, focal_length),
+            lower_left_corner,
             horizontal: horiz,
             vertical: verti,
         }
     }
 
-    pub fn get_ray(&self, u: f32, v: f32) -> Ray {
+    pub fn get_ray(&self, s: f32, t: f32) -> Ray {
         let dir = self.lower_left_corner
-                    + self.horizontal * u
-                    + self.vertical * v 
+                + self.horizontal * s
+                + self.vertical * t 
                 - self.origin;
         Ray{
             orig: self.origin,

src/main.rs

@@ -33,17 +33,37 @@ fn main() {
     
     // world
     
-    let R = std::f32::consts::FRAC_PI_4.cos();
-
-    let mat_left   = Material::Lambertian { albedo: Vec3::new(0.0, 0.0, 1.0) };
-    let mat_right  = Material::Lambertian { albedo: Vec3::new(1.0, 0.0, 0.0) };
+    let mat_ground = Material::Lambertian { albedo: Vec3::new(0.8, 0.8, 0.0) };
+    let mat_center = Material::Lambertian { albedo: Vec3::new(0.1, 0.2, 0.5) };
+    let mat_left   = Material::Dielectric { index_refraction: 1.5 }; 
+    let mat_right  = Material::Metal { albedo: Vec3::new(0.8, 0.6, 0.2), fuzz: 0.0 };
 
     let mut world = HittableList::new();
     world.add(
         Box::new(
             Sphere {
-                center: Vec3::new( -R, 0.0, -1.0),
-                radius: R,
+                center: Vec3::new(0.0, -100.5, -1.0),
+                radius: 100.0,
+                material: Some(mat_ground),
+            }
+        )
+    );
+
+    world.add(
+        Box::new(
+            Sphere {
+                center: Vec3::new(0.0, 0.0, -1.0),
+                radius: 0.5,
+                material: Some(mat_center),
+            }
+        )
+    );
+
+    world.add(
+        Box::new(
+            Sphere {
+                center: Vec3::new(-1.0, 0.0, -1.0),
+                radius: 0.5,
                 material: Some(mat_left),
             }
         )
@@ -52,8 +72,18 @@ fn main() {
     world.add(
         Box::new(
             Sphere {
-                center: Vec3::new( R, 0.0, -1.0),
-                radius: R,
+                center: Vec3::new(-1.0, 0.0, -1.0),
+                radius: -0.45,
+                material: Some(mat_left),
+            }
+        )
+    );
+
+    world.add(
+        Box::new(
+            Sphere {
+                center: Vec3::new(1.0, 0.0, -1.0),
+                radius: 0.5,
                 material: Some(mat_right),
             }
         )
@@ -62,7 +92,13 @@ fn main() {
 
     // camera
 
-    let cam = Camera::new(90.0, aspect_ratio);
+    let cam = Camera::new(
+        Vec3::new(-2.0, 2.0, 1.0),
+        Vec3::new(0.0, 0.0, -1.0),
+        Vec3::new(0.0, 1.0, 0.0),
+        20.0,
+        aspect_ratio
+    );
 
     // render
     let mut small_rng = SmallRng::from_entropy();