📸 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, 18 insertions, 2 deletions

diff --git a/racer-tracer/src/util.rs b/racer-tracer/src/util.rs
index 2f04567..5fb2d36 100644
--- a/racer-tracer/src/util.rs
+++ b/racer-tracer/src/util.rs
@@ -1,6 +1,7 @@
 use rand::Rng;
 
-// For later use
+use crate::vec3::Vec3;
+
 pub fn degrees_to_radians(degrees: f64) -> f64 {
     degrees * std::f64::consts::PI / 180.0
 }
@@ -10,8 +11,23 @@ pub fn random_double() -> f64 {
     rng.gen::<f64>()
 }
 
-// For later use
 pub fn random_double_range(min: f64, max: f64) -> f64 {
     let mut rng = rand::thread_rng();
     rng.gen_range(min..max)
 }
+
+pub fn random_in_unit_disk() -> Vec3 {
+    // TODO: This feels not nice
+    loop {
+        let p = Vec3::new(
+            random_double_range(-1.0, 1.0),
+            random_double_range(-1.0, 1.0),
+            0.0,
+        );
+        if p.length_squared() >= 1.0 {
+            continue;
+        }
+
+        return p;
+    }
+}