1 files changed, 109 insertions, 0 deletions
diff --git a/src/object.rs b/src/object.rs
new file mode 100644
index 0000000..ff965f0
--- /dev/null
+++ b/src/object.rs
@@ -0,0 +1,109 @@
+use crate::calculus::calculus::{Point3, Ray, Vec3};
+
+#[derive(Clone)]
+pub struct HitRecord {
+    pub position: Point3,
+    pub normal: Vec3,
+    pub t: f32,
+    pub front_face: bool,
+}
+
+impl Default for HitRecord {
+    fn default() -> Self {
+        Self {
+            position: Point3 {x:0.0, y:0.0, z:0.0},
+            normal: Vec3 {x:0.0, y:0.0, z:0.0},
+            t: 0.0,
+            front_face: false,
+        }
+    }
+}
+
+impl HitRecord {
+    pub fn set_face_normal(&mut self, r: &Ray, outward_normal: Vec3) {
+        self.front_face = r.direction.dot_prod(&outward_normal) < 0.0;
+        self.normal = if self.front_face { outward_normal } else { outward_normal.scalar_mul(-1.0) };
+    }
+}
+
+pub trait Hittable {
+    fn hit(&self, r: &Ray, ray_tmin: f32, ray_tmax: f32, rec: &mut HitRecord) -> bool;
+}
+
+pub struct Sphere {
+    center: Point3,
+    radius: f32,
+}
+
+impl Sphere {
+    pub fn new(center: Vec3, radius: f32) -> Self {
+        let r = f32::max(0.0, radius);
+        Self { center, radius }
+    }
+}
+
+impl Hittable for Sphere {
+    fn hit(&self, r: &Ray, ray_tmin: f32, ray_tmax: f32, rec: &mut HitRecord) -> bool {
+        let oc = self.center.sub(&r.origin);
+        let a = r.direction.mag_sqr();
+        let h = r.direction.dot_prod(&oc);
+        let c  = oc.mag_sqr() - self.radius * self.radius;
+        let discriminant = h * h - a * c;
+        if discriminant < 0.0 {
+            return false;
+        }
+
+        let sqrtd = discriminant.sqrt();
+
+        let mut root = (h - sqrtd) / a;
+        if root <= ray_tmin || ray_tmax <= root {
+            root = (h + sqrtd) / a;
+            if root <= ray_tmin || ray_tmax <= root {
+                return false;
+            }
+        }
+
+        rec.t = root;
+        rec.position = r.at(rec.t);
+        let outward_normal = rec.normal
+            .sub(&self.center)
+            .scalar_mul(1.0  / self.radius);
+        rec.set_face_normal(r, outward_normal);
+
+        true
+    }
+}
+
+pub struct HittableList {
+    objects: Vec<Box<dyn Hittable>>,
+}
+
+impl HittableList {
+    pub fn new() -> Self {
+        Self { objects: vec![] }
+    }
+
+    pub fn push<T: Hittable + 'static>(&mut self, object: T) {
+        self.objects.push(Box::new(object));
+    }
+}
+
+impl Hittable for HittableList {
+    fn hit(&self, r: &Ray, ray_tmin: f32, ray_tmax: f32, rec: &mut HitRecord) -> bool {
+        let mut temp_rec = HitRecord::default();
+        let mut hit_anything = false;
+        let mut closest_so_far = ray_tmax;
+
+        self.objects.iter().for_each(
+            |object| {
+                if object.hit(r, ray_tmin, closest_so_far, &mut temp_rec) {
+                    hit_anything = true;
+                    closest_so_far = temp_rec.t;
+                    *rec = temp_rec.clone();
+                }
+            }
+        );
+
+        hit_anything
+    }
+}
+\ No newline at end of file