Abstracted lambertian into material

13 files changed, 141 insertions, 49 deletions

diff --git a/src/core/hittable.rs b/src/core/hittable.rs
new file mode 100644
index 0000000..20c82f7
--- /dev/null
+++ b/src/core/hittable.rs
@@ -0,0 +1,23 @@
+use crate::core::{Vector3f, Ray};
+
+/// Returns the context of a intersection
+pub struct Intersection {
+    /// Normal vector at intersection
+    pub n: Vector3f,
+    pub p: Vector3f,
+}
+
+impl Intersection {
+    pub fn norm_against_ray(&self, r: &Ray) -> Vector3f {
+        if self.n.dot(&r.direction) < 0.0 {
+            self.n
+        } else {
+            -self.n
+        }
+    }
+}
+
+/// Defines a common trait for objects in the scene
+pub trait Hittable {
+    fn intersect(&self, ray: &Ray) -> Option<Intersection>;
+}
diff --git a/src/core/mod.rs b/src/core/mod.rs
index 5723b2d..c2b3771 100644
--- a/src/core/mod.rs
+++ b/src/core/mod.rs
@@ -6,6 +6,7 @@ pub mod vector2;
 pub mod vector3;
 pub mod bound;
 pub mod spectrum;
+pub mod hittable;
 mod ray;
 
 pub use vector2::{Vector2i, Vector2f};
@@ -13,3 +14,4 @@ pub use vector3::Vector3f;
 pub use bound::{Bound2i, Bound2f};
 pub use spectrum::Spectrum;
 pub use ray::Ray;
+pub use hittable::{Hittable, Intersection};
diff --git a/src/core/spectrum.rs b/src/core/spectrum.rs
index 727a1b6..9cca7dc 100644
--- a/src/core/spectrum.rs
+++ b/src/core/spectrum.rs
@@ -41,6 +41,18 @@ impl std::ops::Mul<Float> for Spectrum {
     }
 }
 
+impl std::ops::Mul for Spectrum {
+    type Output = Spectrum;
+
+    fn mul(self, op: Self) -> Self::Output {
+        Self::Output::new_rgb(
+            self.c[0] * op.c[0],
+            self.c[1] * op.c[1],
+            self.c[2] * op.c[2],
+            )
+    }
+}
+
 impl std::ops::Div<Float> for Spectrum {
     type Output = Spectrum;
 
diff --git a/src/core/vector3.rs b/src/core/vector3.rs
index ef067aa..ff5a678 100644
--- a/src/core/vector3.rs
+++ b/src/core/vector3.rs
@@ -1,7 +1,7 @@
 //! Implements 3d vectors
 //!
 //! Also add more 3d math things needed for shading and 3d calculations.
-use crate::{Float, Number};
+use crate::{Float, Number, NEAR_ZERO};
 use std::ops::{Mul, Sub, Add, DivAssign, Neg};
 use std::fmt;
 
@@ -149,4 +149,13 @@ impl Vector3f {
             )
 
     }
+
+    /// Check if vector is close to [0, 0, 0]
+    ///
+    /// This is based on the NEAR_ZERO constant
+    pub fn near_zero(&self) -> bool {
+        (self.x.abs() < NEAR_ZERO) &&
+            (self.y.abs() < NEAR_ZERO) &&
+            (self.z.abs() < NEAR_ZERO)
+    }
 }
diff --git a/src/lib.rs b/src/lib.rs
index 7da6627..a0af705 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,6 +4,7 @@ pub mod render;
 pub mod scene;
 pub mod trace;
 pub mod sample;
+pub mod material;
 
 use std::ops::{Add, Sub, Mul, DivAssign, Neg};
 use std::cmp;
@@ -34,3 +35,4 @@ impl Number for f64 {}
 pub type Float = f64;
 
 pub const M_PI: Float = PI;
+pub const NEAR_ZERO: Float = 1e-8;
diff --git a/src/main.rs b/src/main.rs
index 1604ae3..759cbf9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,10 +1,13 @@
 use pathtrace::camera::{Camera, Film, CameraSettings};
-use pathtrace::scene::Scene;
+use pathtrace::scene::{Scene, Object};
 use pathtrace::trace::DefaultTracer;
 use pathtrace::scene::shapes::Sphere;
-use pathtrace::core::{Vector2i, Vector3f};
+use pathtrace::core::{Vector2i, Vector3f, Spectrum};
 use pathtrace::render::{RenderContext, RenderTask};
 use pathtrace::sample::UniformSampler;
+use pathtrace::material::Lambertian;
+
+use std::rc::Rc;
 
 fn main() {
     let res = Vector2i::new_xy(500, 500);
@@ -17,10 +20,13 @@ fn main() {
         screensize: res,
     });
 
+    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 mut scn = Scene::new();
-    scn.add_shapes(vec![
-        Box::new(Sphere::new(0.5, Vector3f::new_xyz(0.0, 0.0, -1.0))),
-        Box::new(Sphere::new(100.0, Vector3f::new_xyz(0.0, -100.5, -1.0))),
+    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(brown.clone(), Box::new(Sphere::new(100.0, Vector3f::new_xyz(0.0, -100.5, -1.0)))),
     ]);
 
     let tracer = DefaultTracer::new(&scn, None);
@@ -32,7 +38,7 @@ fn main() {
     let mut film = Film::new(res);
     let tile = film.get_tile(&film.frame);
 
-    let mut task = RenderTask::new(Box::new(tile), 100);
+    let mut task = RenderTask::new(Box::new(tile), 10);
     task.render(&ctx, &mut sampler);
 
     film.commit_tile(&task.tile);
diff --git a/src/material/lambertian.rs b/src/material/lambertian.rs
new file mode 100644
index 0000000..28d15d3
--- /dev/null
+++ b/src/material/lambertian.rs
@@ -0,0 +1,37 @@
+use super::Material;
+use crate::core::{Intersection, Ray, Spectrum};
+use crate::sample::Sampler;
+
+use std::rc::Rc;
+
+pub struct Lambertian {
+    color: Spectrum,
+}
+
+impl Lambertian {
+    pub fn new(c: Spectrum) -> Lambertian {
+        Lambertian {
+            color: c,
+        }
+    }
+
+    pub fn new_rc(c: Spectrum) -> Rc<dyn Material> {
+        Rc::new(Self::new(c))
+    }
+}
+
+impl Material for Lambertian {
+    fn scatter(&self, ray: &Ray, i: &Intersection, sampler: &mut dyn Sampler) -> Option<(Spectrum, Ray)> {
+        let mut newray = Ray {
+            origin: i.p,
+            direction: i.n + sampler.get_unit_vector(),
+        };
+
+        // Make sure that the resulting direction is not (0, 0, 0)
+        if newray.direction.near_zero() {
+            newray.direction = i.n;
+        }
+
+        Some((self.color.clone(), newray))
+    }
+}
diff --git a/src/material/mod.rs b/src/material/mod.rs
new file mode 100644
index 0000000..62cbf9a
--- /dev/null
+++ b/src/material/mod.rs
@@ -0,0 +1,10 @@
+use crate::core::{Ray, Intersection, Spectrum};
+use crate::sample::Sampler;
+
+mod lambertian;
+
+pub use lambertian::Lambertian;
+
+pub trait Material {
+    fn scatter(&self, ray: &Ray, i: &Intersection, sampler: &mut dyn Sampler) -> Option<(Spectrum, Ray)>;
+}
diff --git a/src/scene/mod.rs b/src/scene/mod.rs
index f8c1e09..cd07236 100644
--- a/src/scene/mod.rs
+++ b/src/scene/mod.rs
@@ -6,27 +6,20 @@ pub mod shapes;
 mod scene;
 pub use scene::*;
 
-use crate::core::{Ray, Vector3f};
-use crate::Float;
+use std::rc::Rc;
+use crate::core::Hittable;
+use crate::material::Material;
 
-/// Returns the context of a intersection
-pub struct Intersection {
-    /// Normal vector at intersection
-    pub n: Vector3f,
-    pub p: Vector3f,
+pub struct Object {
+    pub shape: Box<dyn Hittable>,
+    pub mat: Rc<dyn Material>,
 }
 
-impl Intersection {
-    pub fn norm_against_ray(&self, r: &Ray) -> Vector3f {
-        if self.n.dot(&r.direction) < 0.0 {
-            self.n
-        } else {
-            -self.n
+impl Object {
+    pub fn new(mat: Rc<dyn Material>, shape: Box<dyn Hittable>) -> Self {
+        Object {
+            mat,
+            shape,
         }
     }
 }
-
-/// Defines a common trait for objects in the scene
-pub trait Hittable {
-    fn intersect(&self, ray: &Ray) -> Option<Intersection>;
-}
diff --git a/src/scene/scene.rs b/src/scene/scene.rs
index 367003e..0ffbe97 100644
--- a/src/scene/scene.rs
+++ b/src/scene/scene.rs
@@ -1,33 +1,33 @@
-use super::{Intersection, Hittable};
-use crate::core::Ray;
+use crate::core::{Ray, Intersection, Hittable};
+use crate::material::Material;
 
-type Shape = Box<dyn Hittable>;
+use super::Object;
 
 pub struct Scene {
-    shps: Vec<Shape>,
+    objs: Vec<Object>,
 }
 
 impl Scene {
     pub fn new() -> Self {
         Self {
-            shps: Vec::new(),
+            objs: Vec::new(),
         }
     }
 
-    pub fn add_shape(&mut self, shp: Shape) {
-        self.shps.push(shp);
+    pub fn add_object(&mut self, obj: Object) {
+        self.objs.push(obj);
     }
 
-    pub fn add_shapes(&mut self, shps: Vec<Shape>) {
-        for shp in shps {
-            self.add_shape(shp);
+    pub fn add_objects(&mut self, objs: Vec<Object>) {
+        for obj in objs {
+            self.add_object(obj);
         }
     }
 
-    pub fn intersect(&self, ray: &Ray) -> Option<Intersection> {
-        for shp in self.shps.iter() {
-            if let Some(i) = shp.intersect(&ray) {
-                return Some(i)
+    pub fn intersect(&self, ray: &Ray) -> Option<(&dyn Material, Intersection)> {
+        for obj in self.objs.iter() {
+            if let Some(i) = obj.shape.intersect(&ray) {
+                return Some((obj.mat.as_ref(), i))
             }
         }
 
diff --git a/src/scene/shapes/sphere.rs b/src/scene/shapes/sphere.rs
index acca2b7..3f07b9e 100644
--- a/src/scene/shapes/sphere.rs
+++ b/src/scene/shapes/sphere.rs
@@ -2,8 +2,7 @@
 //!
 //! Spheres are relatively easy to calculate intersections between
 use crate::Float;
-use crate::core::{Ray, Vector3f};
-use crate::scene::{Hittable, Intersection};
+use crate::core::{Ray, Vector3f, Hittable, Intersection};
 
 pub struct Sphere {
     radius: Float,
diff --git a/src/trace/mod.rs b/src/trace/mod.rs
index 7f02f6f..cf06246 100644
--- a/src/trace/mod.rs
+++ b/src/trace/mod.rs
@@ -28,9 +28,9 @@ impl NormTracer<'_> {
 }
 
 impl Tracer for NormTracer<'_> {
-    fn trace(&self, sampler: &mut dyn Sampler, ray: &Ray) -> Spectrum {
-        // Trace ray
-        if let Some(i) = self.scn.intersect(ray) {
+    fn trace(&self, _: &mut dyn Sampler, ray: &Ray) -> Spectrum {
+        // Trace ray, we dont care about material
+        if let Some((_, i)) = self.scn.intersect(ray) {
             let norm = i.n * 0.5 + Vector3f::new(0.5);
 
             return Spectrum::new_rgb(norm.x, norm.y, norm.z);
diff --git a/src/trace/pathtrace.rs b/src/trace/pathtrace.rs
index 32a8e15..a3a688a 100644
--- a/src/trace/pathtrace.rs
+++ b/src/trace/pathtrace.rs
@@ -20,11 +20,10 @@ impl PathTracer<'_> {
 
     pub fn trace_recur(&self, sampler: &mut dyn Sampler, ray: &Ray) -> Spectrum {
 
-        if let Some(i) = self.scn.intersect(ray) {
-            // Get a random direction in the hemisphere a i.p
-            // This is Lambertian reflection
-            let target = i.p + i.n + sampler.get_unit_vector();
-            return self.trace_recur(sampler, &Ray::new_to(i.p, target)) * 0.5;
+        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;
+            }
         }
 
         // Simulates a sky