implement shadows

assignment-1b/Cargo.lock

@@ -28,6 +28,7 @@ dependencies = [
  "num",
  "ordered-float",
  "rayon",
+ "tracing",
 ]
 
 [[package]]
@@ -388,6 +389,12 @@ version = "1.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d01a5bd0424d00070b0098dd17ebca6f961a959dead1dbcbbbc1d1cd8d3deeba"
 
+[[package]]
+name = "pin-project-lite"
+version = "0.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e0a7ae3ac2f1173085d398531c705756c94a4c56843785df85a60c1a0afac116"
+
 [[package]]
 name = "proc-macro-error"
 version = "1.0.4"
@@ -532,6 +539,38 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "tracing"
+version = "0.1.37"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ce8c33a8d48bd45d624a6e523445fd21ec13d3653cd51f681abf67418f54eb8"
+dependencies = [
+ "cfg-if",
+ "pin-project-lite",
+ "tracing-attributes",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-attributes"
+version = "0.1.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4017f8f45139870ca7e672686113917c71c7a6e02d4924eda67186083c03081a"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "tracing-core"
+version = "0.1.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24eb03ba0eab1fd845050058ce5e616558e8f8d8fca633e6b163fe25c797213a"
+dependencies = [
+ "once_cell",
+]
+
 [[package]]
 name = "typenum"
 version = "1.16.0"

assignment-1b/Cargo.toml

@@ -16,3 +16,4 @@ nalgebra = "0.32.1"
 num = { version = "0.4.0", features = ["serde"] }
 ordered-float = "3.4.0"
 rayon = "1.6.1"
+tracing = "0.1.37"

assignment-1b/examples/objects.txt

@@ -5,7 +5,7 @@ hfov 60
 updir 0 1 0
 bkgcolor 0.1 0.1 0.1
 
-depthcueing 0.1 0.1 0.1 1 0.2 100 5
+depthcueing 0.1 0.1 0.1 1 0.2 100 0
 
 light -10 10 -3 0 0.8 0.8 0.8
 light -10 10 -3 1 0.8 0.8 0.8

assignment-1b/src/lib.rs

@@ -4,6 +4,8 @@
 extern crate anyhow;
 #[macro_use]
 extern crate derivative;
+#[macro_use]
+extern crate tracing;
 
 pub mod image;
 pub mod ray;

assignment-1b/src/main.rs

@@ -98,12 +98,13 @@ fn main() -> Result<()> {
       let intersections = scene
         .objects
         .iter()
-        .filter_map(|object| {
+        .enumerate()
+        .filter_map(|(i, object)| {
           match object.kind.intersects_ray_at(&ray) {
             Ok(Some(t)) => {
               // Return both the t and the sphere, because we want to sort on
               // the t but later retrieve attributes from the sphere
-              Some(Ok((t, object)))
+              Some(Ok((i, t, object)))
             }
             Ok(None) => None,
             Err(e) => Some(Err(e)),
@@ -113,13 +114,12 @@ fn main() -> Result<()> {
 
       // Sort the list of intersection times by the lowest one.
       let earliest_intersection =
-        intersections.into_iter().min_by_key(|(t, _)| t.time);
+        intersections.into_iter().min_by_key(|(_, t, _)| t.time);
 
       Ok(match earliest_intersection {
         // Take the object's material color
-        Some((intersection_context, object)) => {
-          scene.compute_pixel_color(object.material, intersection_context)
-        }
+        Some((obj_idx, intersection_context, object)) => scene
+          .compute_pixel_color(obj_idx, object.material, intersection_context),
 
         // There was no intersection, so this should default to the scene's
         // background color

assignment-1b/src/scene/cylinder.rs

@@ -15,12 +15,12 @@ pub struct Cylinder {
   pub length: f64,
 }
 
-impl ObjectKind for Cylinder {
+impl Cylinder {
   /// Given a cylinder, returns the first time at which this ray intersects the
   /// cylinder.
   ///
   /// If there is no intersection point, returns None.
-  fn intersects_ray_at(
+  pub fn intersects_ray_at(
     &self,
     ray: &Ray,
   ) -> Result<Option<IntersectionContext>> {

assignment-1b/src/scene/data.rs

@@ -6,23 +6,38 @@ use nalgebra::Vector3;
 use crate::image::Color;
 use crate::ray::Ray;
 
+use super::cylinder::Cylinder;
 use super::illumination::IntersectionContext;
+use super::sphere::Sphere;
 use super::Scene;
 
-pub trait ObjectKind: Debug + Send + Sync {
+#[derive(Debug)]
+pub enum ObjectKind {
+  Sphere(Sphere),
+  Cylinder(Cylinder),
+}
+
+impl ObjectKind {
   /// Determine where the ray intersects this object, returning the earliest
   /// time this happens. Returns None if no intersection occurs.
   ///
   /// Also known as Trace_Ray in the slides, except not the part where it calls
   /// Shade_Ray.
-  fn intersects_ray_at(&self, ray: &Ray)
-    -> Result<Option<IntersectionContext>>;
+  pub fn intersects_ray_at(
+    &self,
+    ray: &Ray,
+  ) -> Result<Option<IntersectionContext>> {
+    match self {
+      ObjectKind::Sphere(sphere) => sphere.intersects_ray_at(ray),
+      ObjectKind::Cylinder(cylinder) => cylinder.intersects_ray_at(ray),
+    }
+  }
 }
 
 /// An object in the scene
 #[derive(Debug)]
 pub struct Object {
-  pub kind: Box<dyn ObjectKind>,
+  pub kind: ObjectKind,
 
   /// Index into the scene's material color list
   pub material: usize,
@@ -66,12 +81,36 @@ pub struct Light {
   pub color: Vector3<f64>,
 }
 
+impl Light {
+  /// Get the unit directional vector pointing from the given point to this
+  /// light source
+  pub fn direction_from(&self, point: Vector3<f64>) -> Vector3<f64> {
+    match self.kind {
+      LightKind::Point { location } => location - point,
+      LightKind::Directional { direction } => -direction,
+    }
+    .normalize()
+  }
+}
+
 #[derive(Debug)]
 pub struct DepthCueing {
+  /// The color to tint (should be the same as the background color, to avoid
+  /// bizarre visual effects)
   pub color: Color,
+
+  /// Proportion of the color influenced by the depth tint when the distance is
+  /// maxed (caps at 1.0)
   pub a_max: f64,
+
+  /// Proportion of the color influenced by the depth tint when the distance is
+  /// at the minimum (caps at 1.0)
   pub a_min: f64,
+
+  /// The max distance that should be affected by the depth tint
   pub dist_max: f64,
+
+  /// The min distance that should be affected by the depth tint
   pub dist_min: f64,
 }
 

assignment-1b/src/scene/illumination.rs

@@ -1,36 +1,16 @@
+use anyhow::Result;
 use nalgebra::Vector3;
 use ordered_float::NotNan;
-
-use crate::image::Color;
-
-use super::{
-  data::{DepthCueing, LightKind},
-  Scene,
+use rayon::prelude::{
+  IndexedParallelIterator, IntoParallelRefIterator, ParallelIterator,
 };
 
-/// Information about an intersection
-#[derive(Derivative)]
-#[derivative(Debug, PartialEq, PartialOrd, Ord)]
-pub struct IntersectionContext {
-  /// The time of the intersection in the parametric ray
-  ///
-  /// Unfortunately, IEEE floats in Rust don't have total ordering, because
-  /// NaNs violate ordering properties. The way to remedy this is to ensure we
-  /// don't have NaNs by wrapping it into this type, which then implements
-  /// total ordering.
-  pub time: NotNan<f64>,
+use crate::{image::Color, ray::Ray};
 
-  /// The intersection point.
-  #[derivative(PartialEq = "ignore", Ord = "ignore")]
-  pub point: Vector3<f64>,
-
-  /// The normal vector protruding from the surface of the object at the
-  /// intersection point
-  #[derivative(PartialEq = "ignore", Ord = "ignore")]
-  pub normal: Vector3<f64>,
-}
-
-impl Eq for IntersectionContext {}
+use super::{
+  data::{DepthCueing, Light, LightKind},
+  Scene,
+};
 
 impl Scene {
   /// Determine the color that should be used to fill this pixel.
@@ -42,6 +22,7 @@ impl Scene {
   /// Also known as Shade_Ray in the slides.
   pub fn compute_pixel_color(
     &self,
+    obj_idx: usize,
     material_idx: usize,
     intersection_context: IntersectionContext,
   ) -> Color {
@@ -57,16 +38,10 @@ impl Scene {
     // Diffuse and specular lighting for each separate light
     let diffuse_and_specular: Vector3<f64> = self
       .lights
-      .iter()
+      .par_iter()
       .map(|light| {
         // The vector pointing in the direction of the light
-        let light_direction = match light.kind {
-          LightKind::Point { location } => {
-            location - intersection_context.point
-          }
-          LightKind::Directional { direction } => -direction,
-        }
-        .normalize();
+        let light_direction = light.direction_from(intersection_context.point);
 
         let normal = intersection_context.normal.normalize();
         let viewer_direction = self.eye_pos - intersection_context.point;
@@ -84,8 +59,14 @@ impl Scene {
             .max(0.0)
             .powf(material.exponent);
 
+        let shadow_flag =
+          match self.in_shadow_of(obj_idx, intersection_context.point, light) {
+            true => 0.0,
+            false => 1.0,
+          };
+
         let diffuse_and_specular = diffuse_component + specular_component;
-        light.color.component_mul(&diffuse_and_specular)
+        shadow_flag * light.color.component_mul(&diffuse_and_specular)
       })
       .sum();
 
@@ -119,4 +100,93 @@ impl Scene {
 
     clamped_result
   }
+
+  /// Perform another ray casting to see if there are any objects obstructing
+  /// the light source to this particular point
+  pub fn in_shadow_of(
+    &self,
+    obj_idx: usize,
+    point: Vector3<f64>,
+    light: &Light,
+  ) -> bool {
+    let light_direction = light.direction_from(point);
+    let ray = Ray {
+      origin: point,
+      direction: light_direction.normalize(),
+    };
+
+    // Small helper for iterating over all of the objects in the scene except
+    // for the current one
+    let other_objects = self
+      .objects
+      .par_iter()
+      .enumerate()
+      .filter(|(i, _)| *i != obj_idx);
+
+    // Get the list of intersections with all the other objects in the scene
+    let intersections = other_objects
+      .filter_map(|(_, object)| {
+        let intersection_context = match object.kind.intersects_ray_at(&ray) {
+          Ok(v) => v,
+          Err(err) => {
+            error!("Error while performing shadow casting: {err}");
+            None
+          }
+        }?;
+
+        match light.kind {
+          // In the case of point lights, we must check to see if both t > 0 and
+          // t is less than the time it took to even get to the light.
+          LightKind::Point { location } => {
+            let light_time = (location - ray.origin).norm();
+            let intersection_time = *intersection_context.time;
+
+            if intersection_time <= 0.0 || intersection_time >= light_time {
+              None
+            } else {
+              Some(intersection_context)
+            }
+          }
+
+          // In the case of directional lights, only t > 0 needs to be checked,
+          // otherwise
+          LightKind::Directional { .. } => {
+            if *intersection_context.time <= 0.0 {
+              None
+            } else {
+              Some(intersection_context)
+            }
+          }
+        }
+      })
+      .collect::<Vec<_>>();
+
+    !intersections.is_empty()
+  }
 }
+
+/// Information about an intersection
+#[derive(Derivative)]
+#[derivative(Debug, PartialEq, PartialOrd, Ord)]
+pub struct IntersectionContext {
+  /// The time of the intersection in the parametric ray
+  ///
+  /// Unfortunately, IEEE floats in Rust don't have total ordering, because
+  /// NaNs violate ordering properties. The way to remedy this is to ensure we
+  /// don't have NaNs by wrapping it into this type, which then implements
+  /// total ordering.
+  pub time: NotNan<f64>,
+
+  /// The intersection point.
+  #[derivative(PartialEq = "ignore", Ord = "ignore")]
+  pub point: Vector3<f64>,
+
+  /// The normal vector protruding from the surface of the object at the
+  /// intersection point
+  #[derivative(PartialEq = "ignore", Ord = "ignore")]
+  pub normal: Vector3<f64>,
+}
+
+impl Eq for IntersectionContext {}
+
+impl IntersectionContext {}

assignment-1b/src/scene/input_file.rs

@@ -10,7 +10,7 @@ use crate::scene::{
   Scene,
 };
 
-use super::data::DepthCueing;
+use super::data::{DepthCueing, ObjectKind};
 
 impl Scene {
   /// Parse the input file into a scene
@@ -125,7 +125,7 @@ impl Scene {
           }
 
           "sphere" => scene.objects.push(Object {
-            kind: Box::new(Sphere {
+            kind: ObjectKind::Sphere(Sphere {
               center: read_vec3(0)?,
               radius: parts[3],
             }),
@@ -138,7 +138,7 @@ impl Scene {
           }),
 
           "cylinder" => scene.objects.push(Object {
-            kind: Box::new(Cylinder {
+            kind: ObjectKind::Cylinder(Cylinder {
               center: read_vec3(0)?,
               direction: read_vec3(3)?,
               radius: parts[6],

assignment-1b/src/scene/mod.rs

@@ -1,8 +1,8 @@
 pub mod cylinder;
 pub mod data;
+pub mod illumination;
 pub mod input_file;
 pub mod sphere;
-pub mod illumination;
 
 use nalgebra::Vector3;
 

assignment-1b/src/scene/sphere.rs

@@ -12,12 +12,12 @@ pub struct Sphere {
   pub radius: f64,
 }
 
-impl ObjectKind for Sphere {
+impl Sphere {
   /// Given a sphere, returns the first time at which this ray intersects the
   /// sphere.
   ///
   /// If there is no intersection point, returns None.
-  fn intersects_ray_at(
+  pub fn intersects_ray_at(
     &self,
     ray: &Ray,
   ) -> Result<Option<IntersectionContext>> {

flake.nix

@@ -13,14 +13,15 @@
       in rec {
         devShell = pkgs.mkShell {
           packages = (with pkgs; [
-            cargo-watch
             cargo-deny
             cargo-edit
-            pandoc
-            zip
-            unzip
-            texlive.combined.scheme-full
+            cargo-flamegraph
+            cargo-watch
             imagemagick
+            pandoc
+            texlive.combined.scheme-full
+            unzip
+            zip
 
             (python310.withPackages (p: with p; [ numpy ]))
           ]) ++ (with toolchain; [