library: render: object: add deserialization

By using `enum_dispatch` and deserializing the enums, you can very
easily represent the `Object` in serialized form.

src/render/object.rs

@@ -1,9 +1,10 @@
 use crate::material::MaterialEnum;
 use crate::shape::ShapeEnum;
 use crate::texture::TextureEnum;
+use serde::Deserialize;
 
 /// An object being rendered in the scene.
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Deserialize)]
 pub struct Object {
     pub shape: ShapeEnum,
     pub material: MaterialEnum,
@@ -29,22 +30,28 @@ mod test {
     use crate::texture::UniformTexture;
     use crate::Point;
 
-    #[test]
-    fn new_works() {
-        let shape = Sphere::new(Point::origin(), 1.);
+    fn simple_object() -> Object {
+        let shape = Sphere::new(Point::new(5., 0., 0.), 1.);
         let material = UniformMaterial::new(
             LinearColor::new(0.5, 0.5, 0.5),
             LinearColor::new(1., 1., 1.),
             0.5,
         );
         let texture = UniformTexture::new(LinearColor::new(0.25, 0.5, 1.));
-        let object = Object::new(
-            shape.clone().into(),
-            material.clone().into(),
-            texture.clone().into(),
+        Object::new(shape.into(), material.into(), texture.into())
+    }
+
+    #[test]
+    fn new_works() {
+        let shape = Sphere::new(Point::new(5., 0., 0.), 1.);
+        let material = UniformMaterial::new(
+            LinearColor::new(0.5, 0.5, 0.5),
+            LinearColor::new(1., 1., 1.),
+            0.5,
         );
+        let texture = UniformTexture::new(LinearColor::new(0.25, 0.5, 1.));
         assert_eq!(
-            object,
+            simple_object(),
             Object {
                 shape: shape.into(),
                 material: material.into(),
@@ -52,4 +59,26 @@ mod test {
             }
         )
     }
+
+    #[test]
+    fn deserialization_works() {
+        let yaml = r#"
+            shape:
+              type: sphere
+              inverted: false
+              center: [5., 0.0, 0.0]
+              radius: 1.0
+            material:
+              type: uniform
+              diffuse: {r: 0.5, g: 0.5, b: 0.5}
+              specular: {r: 1., g: 1., b: 1.}
+              reflectivity: 0.5
+            texture:
+              type: uniform
+              color: {r: 0.25, g: 0.5, b: 1.}
+        "#;
+        let object: Object = serde_yaml::from_str(yaml).unwrap();
+        let expected = simple_object();
+        assert_eq!(object, expected)
+    }
 }