📸 Add Camera defocus blur + Other

Just wanted to add defocus blur but ended up changing a bunch of other
this as well.

- Moved scenes to a separate folder.
- Updated readme with more pretty images.
- Add interface for loading scenes. There is currently one for yaml
  and another if you want a slightly random scene.
- Add image action to decide what to do with the final image once its
  rendered. Currently supports just showing the buffer until you press
  the render buffer again and saving the image as `png`.
- When you use nix shell you will be dropped in the proper folder so
  you can just do cargo build etc without having to do `cd`.

1 files changed, 87 insertions, 0 deletions

diff --git a/racer-tracer/src/scene/random.rs b/racer-tracer/src/scene/random.rs
new file mode 100644
index 0000000..ddbcfc1
--- /dev/null
+++ b/racer-tracer/src/scene/random.rs
@@ -0,0 +1,87 @@
+use std::sync::Arc;
+
+use crate::{
+    error::TracerError,
+    geometry::{sphere::Sphere, Hittable},
+    material::{dialectric::Dialectric, lambertian::Lambertian, metal::Metal, SharedMaterial},
+    scene::SceneLoader,
+    util::{random_double, random_double_range},
+    vec3::{Color, Vec3},
+};
+
+pub struct Random {}
+
+impl Random {
+    pub fn new() -> Self {
+        Self {}
+    }
+}
+
+impl SceneLoader for Random {
+    fn load(&self) -> Result<Vec<Box<dyn crate::geometry::Hittable>>, TracerError> {
+        let mut geometry: Vec<Box<dyn Hittable>> = Vec::new();
+        let ground_material: SharedMaterial =
+            Arc::new(Box::new(Lambertian::new(Color::new(0.5, 0.5, 0.5))));
+        geometry.push(Box::new(Sphere::new(
+            Vec3::new(0.0, -1000.0, 0.0),
+            1000.0,
+            ground_material,
+        )));
+
+        for a in -11..11 {
+            for b in -11..11 {
+                let choose_mat = random_double();
+                let center = Vec3::new(
+                    a as f64 + 0.9 * random_double(),
+                    0.2,
+                    b as f64 + 0.9 * random_double(),
+                );
+
+                if (center - Vec3::new(4.0, 0.2, 0.0)).length() > 0.9 {
+                    if choose_mat < 0.8 {
+                        // diffuse
+                        let albedo = Color::random() * Color::random();
+                        let mat: SharedMaterial = Arc::new(Box::new(Lambertian::new(albedo)));
+                        geometry.push(Box::new(Sphere::new(center, 0.2, mat)));
+                    } else if choose_mat > 0.95 {
+                        // metal
+                        let albedo = Color::random_range(0.5, 1.0);
+                        let fuzz = random_double_range(0.0, 0.5);
+                        let mat: SharedMaterial = Arc::new(Box::new(Metal::new(albedo, fuzz)));
+                        geometry.push(Box::new(Sphere::new(center, 0.2, mat)));
+                    } else {
+                        // glass
+                        let mat: SharedMaterial = Arc::new(Box::new(Dialectric::new(1.5)));
+                        geometry.push(Box::new(Sphere::new(center, 0.2, mat)));
+                    }
+                }
+            }
+        }
+
+        let dial_mat: SharedMaterial = Arc::new(Box::new(Dialectric::new(1.5)));
+        geometry.push(Box::new(Sphere::new(
+            Vec3::new(0.0, 1.0, 0.0),
+            1.0,
+            dial_mat,
+        )));
+
+        let lamb_mat: SharedMaterial =
+            Arc::new(Box::new(Lambertian::new(Color::new(0.4, 0.2, 0.1))));
+        geometry.push(Box::new(Sphere::new(
+            Vec3::new(-4.0, 1.0, 0.0),
+            1.0,
+            lamb_mat,
+        )));
+
+        let metal_mat: SharedMaterial =
+            Arc::new(Box::new(Metal::new(Color::new(0.7, 0.6, 0.5), 0.0)));
+
+        geometry.push(Box::new(Sphere::new(
+            Vec3::new(4.0, 1.0, 0.0),
+            1.0,
+            metal_mat,
+        )));
+
+        Ok(geometry)
+    }
+}