From ff625f576fefcbfd62dace5d75aadaff437d8f28 Mon Sep 17 00:00:00 2001
From: bijan2005 <rhombusesarekites>
Date: Mon, 30 Nov 2020 09:41:15 -0500
Subject: [PATCH] Add generic trait Surface

---
 src/main.rs          |  5 ++---
 src/object.rs        | 25 ++++++++-----------------
 src/object/base.rs   | 14 ++++++++++++++
 src/object/plane.rs  | 11 +++++++----
 src/object/sphere.rs | 17 +++++++++--------
 5 files changed, 40 insertions(+), 32 deletions(-)
 create mode 100644 src/object/base.rs

diff --git a/src/main.rs b/src/main.rs
index 8bdd402..e2fe974 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -52,11 +52,10 @@ fn render(camera: &Camera, scene: &Scene, filename: &str) -> std::io::Result<()>
 
 fn main() -> std::io::Result<()> {
 
-    let camera = Camera::new(Point3::new(0.0,0.0,0.0), Vector3::new(0.0,0.0,-1.0), 1.0, 2.0, 2.0, 400, 400);
+    let camera = Camera::new(Point3::new(0.0,0.0,0.0), Vector3::new(0.0,0.0,-1.0), 1.0, 2.0, 2.0, 500, 500);
 
     let scene = vec![
-        Object::Sphere(Sphere::new_solid(0.0,0.0,-5.0,2.0, Color::white())),
-        Object::Sphere(Sphere::new_solid(-3.0,0.0,-8.0,2.5, Color::white()))
+        Object::new(Sphere::new(0.0,0.0,-3.0,2.0, |x, y| Color::new(x, 0.0, y * 2.0)))
     ];
 
     render(&camera, &scene, "out.ppm")
diff --git a/src/object.rs b/src/object.rs
index 9be2ca6..6b7d272 100644
--- a/src/object.rs
+++ b/src/object.rs
@@ -1,4 +1,5 @@
 
+mod base; pub use base::*;
 mod sphere; pub use sphere::*;
 mod plane; pub use plane::*;
 mod triangle; pub use triangle::*;
@@ -7,28 +8,18 @@ use na::*;
 
 use crate::types::*;
 
-pub enum Object {
-    Sphere(Sphere)
+pub struct Object {
+    pub surface: Box<dyn Surface>
 }
 
 impl Object {
-    pub fn intersect(&self, ray: Ray) -> Option<f32> {
-        match *self {
-            Object::Sphere(ref sphere) => sphere.intersect(ray)
-        }
+    pub fn new<S: 'static + Surface>(surface: S) -> Self {
+        Object { surface: Box::new(surface) }
     }
 
-    pub fn getcolor(&self, point: Point3<f32>) -> Color {
-        match *self {
-            Object::Sphere(ref sphere) => sphere.getcolor(point)
-        }
-    }
-
-    pub fn normal(&self, point: Point3<f32>) -> Unit<Vector3<f32>> {
-        match *self {
-            Object::Sphere(ref sphere) => sphere.normal(point)
-        }
-    }
+    pub fn intersect(&self, ray: Ray) -> Option<f32> { self.surface.intersect(ray) }
+    pub fn normal(&self, point: Point3<f32>) -> Unit<Vector3<f32>> { self.surface.normal(point) }
+    pub fn getcolor(&self, point: Point3<f32>) -> Color { self.surface.getcolor(point) }
 }
 
 pub type Scene = Vec<Object>;
diff --git a/src/object/base.rs b/src/object/base.rs
new file mode 100644
index 0000000..c8489ce
--- /dev/null
+++ b/src/object/base.rs
@@ -0,0 +1,14 @@
+extern crate nalgebra as na;
+
+use na::*;
+use na::geometry::Point3;
+
+use crate::types::*;
+
+pub trait Surface {
+    fn intersect(&self, ray: Ray) -> Option<f32>;
+
+    fn normal(&self, point: Point3<f32>) -> Unit<Vector3<f32>>;
+
+    fn getcolor(&self, point: Point3<f32>) -> Color;
+}
diff --git a/src/object/plane.rs b/src/object/plane.rs
index 8e50e51..a32a039 100644
--- a/src/object/plane.rs
+++ b/src/object/plane.rs
@@ -4,6 +4,7 @@ use na::*;
 use na::geometry::Point3;
 
 use crate::types::*;
+use super::base::*;
 
 pub struct Plane {
     pub center: Point3<f32>,
@@ -25,8 +26,10 @@ impl Plane {
 
     pub fn new_solid(center: Point3<f32>, normal: Vector3<f32>, color: Color) -> Self
         { Plane::new(center, normal, move |_, _| color) }
+}
 
-    pub fn intersect(&self, ray: Ray) -> Option<f32> {
+impl Surface for Plane {
+    fn intersect(&self, ray: Ray) -> Option<f32> {
 
         let d = self.normal.dot(&ray.direction);
         if d < 1e-6 { return None; }
@@ -37,9 +40,9 @@ impl Plane {
         else { None }
     }
 
-    pub fn getcolor(&self, point: Point3<f32>) -> Color {
+    fn normal(&self, _point: Point3<f32>) -> Unit<Vector3<f32>> { self.normal }
+
+    fn getcolor(&self, point: Point3<f32>) -> Color {
         unimplemented!()
     }
-
-    pub fn normal(&self, point: Point3<f32>) -> Unit<Vector3<f32>> { self.normal }
 }
diff --git a/src/object/sphere.rs b/src/object/sphere.rs
index 42e19fe..b91848d 100644
--- a/src/object/sphere.rs
+++ b/src/object/sphere.rs
@@ -6,6 +6,7 @@ use na::*;
 use na::geometry::Point3;
 
 use crate::types::*;
+use super::base::*;
 
 pub struct Sphere {
     pub center: Point3<f32>,
@@ -27,10 +28,10 @@ impl Sphere {
 
     pub fn new_solid(x: f32, y: f32, z: f32, radius: f32, color: Color) -> Self
         { Sphere::new(x, y, z, radius, move |_, _| color) }
+}
 
-    // Determines if a ray intersects the circle.
-    // If so, returns the distance to the intersection point.
-    pub fn intersect(&self, ray: Ray) -> Option<f32> {
+impl Surface for Sphere {
+    fn intersect(&self, ray: Ray) -> Option<f32> {
         fn solve_quadratic(a: f32, b: f32, c: f32) -> Option<(f32, f32)> {
             let discr = b * b - 4.0 * a * c;
 
@@ -58,7 +59,11 @@ impl Sphere {
         else { None }
     }
 
-    pub fn getcolor(&self, point: Point3<f32>) -> Color {
+    fn normal(&self, point: Point3<f32>) -> Unit<Vector3<f32>> {
+        Unit::new_normalize(point - self.center)
+    }
+
+    fn getcolor(&self, point: Point3<f32>) -> Color {
         let normal = self.normal(point);
 
         // In this particular case, the normal is simular to a point on a unit sphere
@@ -71,8 +76,4 @@ impl Sphere {
 
         (*self.texture)(x, y)
     }
-
-    pub fn normal(&self, point: Point3<f32>) -> Unit<Vector3<f32>> {
-        Unit::new_normalize(point - self.center)
-    }
 }