library: core: camera: add deserialization

src/core/camera.rs

@@ -1,5 +1,6 @@
 use super::film::Film;
 use crate::{Point, Vector};
+use serde::{Deserialize, Deserializer};
 
 /// Represent an abstract camera to observe the scene.
 #[derive(Debug, PartialEq)]
@@ -19,7 +20,7 @@ impl Camera {
         dist_to_image: f32,
         x: u32,
         y: u32,
-    ) -> Camera {
+    ) -> Self {
         let right = forward.cross(&up);
         let center = origin + forward.normalize() * dist_to_image;
         let screen_size = 2. * f32::tan(fov / 2.) * dist_to_image;
@@ -36,6 +37,41 @@ impl Camera {
     }
 }
 
+#[derive(Debug, Deserialize)]
+struct SerializedCamera {
+    origin: Point,
+    forward: Vector,
+    up: Vector,
+    fov: f32,
+    distance_to_image: f32,
+    x: u32,
+    y: u32,
+}
+
+impl From<SerializedCamera> for Camera {
+    fn from(cam: SerializedCamera) -> Self {
+        Camera::new(
+            cam.origin,
+            cam.forward,
+            cam.up,
+            std::f32::consts::PI * cam.fov / 180.,
+            cam.distance_to_image,
+            cam.x,
+            cam.y,
+        )
+    }
+}
+
+impl<'de> Deserialize<'de> for Camera {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let cam: SerializedCamera = Deserialize::deserialize(deserializer)?;
+        Ok(cam.into())
+    }
+}
+
 #[cfg(test)]
 mod test {
     use super::*;
@@ -66,4 +102,32 @@ mod test {
             }
         )
     }
+
+    #[test]
+    fn deserialization_works() {
+        let yaml = r#"
+            origin: [-1.0, 0.0, 0.0]
+            forward: [ 1.0, 0.0, 0.0]
+            up: [0.0, 1.0, 0.0]
+            fov: 90.0
+            distance_to_image: 1.0
+            x: 1080
+            y: 1080
+        "#;
+        let cam: Camera = serde_yaml::from_str(yaml).unwrap();
+        assert_eq!(
+            cam,
+            Camera {
+                origin: Point::new(-1., 0., 0.),
+                film: Film::new(
+                    1080,
+                    1080,
+                    2.,
+                    Point::origin(),
+                    Vector::new(0., 1., 0.),
+                    Vector::new(0., 0., 1.),
+                )
+            }
+        )
+    }
 }