Add reflecting material

8 files changed, 77 insertions, 10 deletions

diff --git a/src/core/ray.rs b/src/core/ray.rs
index c944184..0517e50 100644
--- a/src/core/ray.rs
+++ b/src/core/ray.rs
@@ -8,6 +8,13 @@ pub struct Ray {
 }
 
 impl Ray {
+    pub fn new(origin: Vector3f, direction: Vector3f) -> Ray {
+        Ray {
+            origin,
+            direction,
+        }
+    }
+
     pub fn new_to(origin: Vector3f, target: Vector3f) -> Ray {
         let dir = (target - origin).norm();
         Ray {
diff --git a/src/core/spectrum.rs b/src/core/spectrum.rs
index 9cca7dc..c33d3af 100644
--- a/src/core/spectrum.rs
+++ b/src/core/spectrum.rs
@@ -12,6 +12,8 @@ pub struct Spectrum {
 }
 
 impl Spectrum {
+    pub const ZERO: Self = Spectrum { c: [0.0; 3] };
+
     pub fn new_rgb(r: Float, g: Float, b: Float) -> Spectrum {
         Spectrum { c: [r, g, b] }
     }
diff --git a/src/core/vector3.rs b/src/core/vector3.rs
index ff5a678..9d6c1cf 100644
--- a/src/core/vector3.rs
+++ b/src/core/vector3.rs
@@ -2,7 +2,7 @@
 //!
 //! Also add more 3d math things needed for shading and 3d calculations.
 use crate::{Float, Number, NEAR_ZERO};
-use std::ops::{Mul, Sub, Add, DivAssign, Neg};
+use std::ops::{Mul, Sub, Add, DivAssign, Neg, AddAssign};
 use std::fmt;
 
 #[derive(Clone, Copy)]
@@ -85,6 +85,14 @@ impl<T: Number> Neg for Vector3<T> {
     }
 }
 
+impl<T: Number> AddAssign<&Self> for Vector3<T> {
+    fn add_assign(&mut self, op: &Self) {
+        self.x += op.x;
+        self.y += op.y;
+        self.z += op.z;
+    }
+}
+
 impl<T: Number> DivAssign<T> for Vector3<T> {
     fn div_assign(&mut self, op: T) {
         self.x /= op;
diff --git a/src/lib.rs b/src/lib.rs
index a0af705..1593471 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -6,7 +6,7 @@ pub mod trace;
 pub mod sample;
 pub mod material;
 
-use std::ops::{Add, Sub, Mul, DivAssign, Neg};
+use std::ops::{Add, Sub, Mul, DivAssign, AddAssign, Neg};
 use std::cmp;
 use std::fmt;
 use std::f64::consts::PI;
@@ -22,6 +22,7 @@ pub trait Number:
     Mul<Output = Self> +
     Neg<Output = Self> + 
     DivAssign +
+    AddAssign +
     fmt::Display
 {}
 
diff --git a/src/main.rs b/src/main.rs
index 759cbf9..ac197a1 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,7 +5,7 @@ use pathtrace::scene::shapes::Sphere;
 use pathtrace::core::{Vector2i, Vector3f, Spectrum};
 use pathtrace::render::{RenderContext, RenderTask};
 use pathtrace::sample::UniformSampler;
-use pathtrace::material::Lambertian;
+use pathtrace::material::{Reflectant, Lambertian};
 
 use std::rc::Rc;
 
@@ -13,8 +13,8 @@ fn main() {
     let res = Vector2i::new_xy(500, 500);
 
     let cam = Camera::new(&CameraSettings {
-        target: Vector3f::new_xyz(0.0, 0.0, -1.0),
-        origin: Vector3f::new_xyz(0.0, 0.0, 0.0),
+        target: Vector3f::new_xyz(0.5, 0.0, -1.0),
+        origin: Vector3f::new_xyz(0.0, 0.0, 0.5),
         up: Vector3f::new_xyz(0.0, 1.0, 0.0),
         fov: 90.0, 
         screensize: res,
@@ -22,10 +22,12 @@ fn main() {
 
     let brown = Rc::new(Lambertian::new(Spectrum::new_rgb(0.5, 0.3, 0.0)));
     let blue = Rc::new(Lambertian::new(Spectrum::new_rgb(0.0, 0.3, 0.7)));
+    let metal = Rc::new(Reflectant::new(Spectrum::new_rgb(0.75, 0.75, 0.75), Some(0.1)));
 
     let mut scn = Scene::new();
     scn.add_objects(vec![
-        Object::new(blue.clone(), Box::new(Sphere::new(0.5, Vector3f::new_xyz(0.0, 0.0, -1.0)))),
+        Object::new(metal.clone(), Box::new(Sphere::new(0.5, Vector3f::new_xyz(0.0, 0.0, -1.0)))),
+        Object::new(blue.clone(), Box::new(Sphere::new(0.5, Vector3f::new_xyz(1.0, 0.0, -1.0)))),
         Object::new(brown.clone(), Box::new(Sphere::new(100.0, Vector3f::new_xyz(0.0, -100.5, -1.0)))),
     ]);
 
@@ -38,7 +40,7 @@ fn main() {
     let mut film = Film::new(res);
     let tile = film.get_tile(&film.frame);
 
-    let mut task = RenderTask::new(Box::new(tile), 10);
+    let mut task = RenderTask::new(Box::new(tile), 100);
     task.render(&ctx, &mut sampler);
 
     film.commit_tile(&task.tile);
diff --git a/src/material/mod.rs b/src/material/mod.rs
index 62cbf9a..c939385 100644
--- a/src/material/mod.rs
+++ b/src/material/mod.rs
@@ -2,8 +2,10 @@ use crate::core::{Ray, Intersection, Spectrum};
 use crate::sample::Sampler;
 
 mod lambertian;
+mod reflectant;
 
 pub use lambertian::Lambertian;
+pub use reflectant::Reflectant;
 
 pub trait Material {
     fn scatter(&self, ray: &Ray, i: &Intersection, sampler: &mut dyn Sampler) -> Option<(Spectrum, Ray)>;
diff --git a/src/material/reflectant.rs b/src/material/reflectant.rs
new file mode 100644
index 0000000..f4b110c
--- /dev/null
+++ b/src/material/reflectant.rs
@@ -0,0 +1,39 @@
+use crate::Float;
+use crate::core::{Ray, Intersection, Spectrum, Vector3f};
+use super::Material;
+use crate::sample::Sampler;
+
+pub struct Reflectant {
+    color: Spectrum,
+    fuzz: Option<Float>,
+}
+
+impl Reflectant {
+    pub fn new(c: Spectrum, fuzz: Option<Float>) -> Reflectant {
+        Reflectant {
+            color: c,
+            fuzz,
+        }
+    }
+}
+
+fn reflect(v: &Vector3f, n: &Vector3f) -> Vector3f {
+    *v - *n * (2.0 * v.dot(n))
+}
+
+impl Material for Reflectant {
+    fn scatter(&self, ray: &Ray, i: &Intersection, sampler: &mut dyn Sampler) -> Option<(Spectrum, Ray)> {
+        // Find reflectance vector
+        let mut reflected = reflect(&ray.direction, &i.n);
+        if let Some(fuzz) = self.fuzz {
+            reflected += &(sampler.get_unit_vector() * fuzz);
+        }
+
+        Some((
+                self.color,
+                Ray::new(i.p, reflected.norm()),
+                ))
+    }
+}
+
+
diff --git a/src/trace/pathtrace.rs b/src/trace/pathtrace.rs
index a3a688a..811b653 100644
--- a/src/trace/pathtrace.rs
+++ b/src/trace/pathtrace.rs
@@ -18,11 +18,17 @@ impl PathTracer<'_> {
         }
     }
 
-    pub fn trace_recur(&self, sampler: &mut dyn Sampler, ray: &Ray) -> Spectrum {
+    pub fn trace_recur(&self, sampler: &mut dyn Sampler, ray: &Ray, depth: i32) -> Spectrum {
+
+        if depth == 0 {
+            return Spectrum::ZERO;
+        }
 
         if let Some((mat, i)) = self.scn.intersect(ray) {
             if let Some((scalar, nray)) = mat.scatter(ray, &i, sampler) {
-                return self.trace_recur(sampler, &nray) * scalar;
+                return self.trace_recur(sampler, &nray, depth-1) * scalar;
+            } else {
+                return Spectrum::ZERO;
             }
         }
 
@@ -35,6 +41,6 @@ impl PathTracer<'_> {
 
 impl Tracer for PathTracer<'_> {
     fn trace(&self, sampler: &mut dyn Sampler, ray: &Ray) -> Spectrum {
-        self.trace_recur(sampler, ray)
+        self.trace_recur(sampler, ray, self.depth)
     }
 }