Fix the weird other reflection

assignment-1d/Cargo.lock

@@ -52,6 +52,7 @@ dependencies = [
  "rand",
  "rayon",
  "tracing",
+ "tracing-appender",
  "tracing-subscriber",
 ]
 
@@ -785,6 +786,33 @@ dependencies = [
  "once_cell",
 ]
 
+[[package]]
+name = "time"
+version = "0.3.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cd0cbfecb4d19b5ea75bb31ad904eb5b9fa13f21079c3b92017ebdf4999a5890"
+dependencies = [
+ "itoa",
+ "serde",
+ "time-core",
+ "time-macros",
+]
+
+[[package]]
+name = "time-core"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2e153e1f1acaef8acc537e68b44906d2db6436e2b35ac2c6b42640fff91f00fd"
+
+[[package]]
+name = "time-macros"
+version = "0.2.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fd80a657e71da814b8e5d60d3374fc6d35045062245d80224748ae522dd76f36"
+dependencies = [
+ "time-core",
+]
+
 [[package]]
 name = "tracing"
 version = "0.1.37"
@@ -797,6 +825,17 @@ dependencies = [
  "tracing-core",
 ]
 
+[[package]]
+name = "tracing-appender"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09d48f71a791638519505cefafe162606f706c25592e4bde4d97600c0195312e"
+dependencies = [
+ "crossbeam-channel",
+ "time",
+ "tracing-subscriber",
+]
+
 [[package]]
 name = "tracing-attributes"
 version = "0.1.23"

assignment-1d/Cargo.toml

@@ -32,4 +32,5 @@ ordered-float = "3.4.0"
 rand = "0.8.5"
 rayon = "1.6.1"
 tracing = "0.1.37"
+tracing-appender = "0.2.2"
 tracing-subscriber = { version = "0.3.16", features = ["json"] }

assignment-1d/src/main.rs

@@ -1,8 +1,10 @@
 #[macro_use]
+extern crate anyhow;
+#[macro_use]
 extern crate tracing;
 
-use std::fs::File;
 use std::path::PathBuf;
+use std::{fs::File, str::FromStr};
 
 use anyhow::Result;
 use assignment_1d::{image::Image, ray::Ray, scene::Scene};
@@ -11,6 +13,7 @@ use clap::{ArgAction, Parser};
 
 use rayon::prelude::{IntoParallelIterator, ParallelIterator};
 use tracing::metadata::LevelFilter;
+use tracing_appender::non_blocking::WorkerGuard;
 use tracing_subscriber::{
   fmt::Layer, prelude::__tracing_subscriber_SubscriberExt,
   util::SubscriberInitExt,
@@ -29,6 +32,14 @@ struct Opt {
   #[clap(short = 'o', long = "output")]
   output_path: Option<PathBuf>,
 
+  /// Log output in json
+  #[clap(long = "json")]
+  use_json: bool,
+
+  /// Which file to send logs to (stderr by default)
+  #[clap(long = "log-output")]
+  log_output: Option<PathBuf>,
+
   /// Force parallel projection to be used
   #[clap(long = "parallel")]
   force_parallel: bool,
@@ -40,30 +51,16 @@ struct Opt {
   /// Verbosity
   #[clap(short, long, action = ArgAction::Count)]
   verbosity: u8,
+
+  /// Evaluate at a single pixel
+  #[clap(short, long = "render-pixel")]
+  render_pixel: Option<RenderPixel>,
 }
 
 fn main() -> Result<()> {
   let opt = Opt::parse();
 
-  let level_filter = match opt.verbosity {
-    0 => LevelFilter::ERROR,
-    1 => LevelFilter::WARN,
-    2 => LevelFilter::INFO,
-    3 => LevelFilter::DEBUG,
-    _ => LevelFilter::TRACE,
-  };
-
-  // Set up logging
-  let layer = Layer::default()
-    .json()
-    .with_target(false)
-    .with_timer(tracing_subscriber::fmt::time::uptime())
-    .with_level(true);
-
-  tracing_subscriber::registry()
-    .with(layer)
-    .with(level_filter)
-    .init();
+  let _guard = setup_logging(&opt);
 
   // Rename the output file if it's not provided
   let out_file = opt
@@ -81,6 +78,37 @@ fn main() -> Result<()> {
   // Translate image pixels to real-world 3d coords
   let translate_pixel = scene.pixel_translation_function(distance);
 
+  let evaluate_at_pixel = |px, py| {
+    let span = trace_span!("main_loop", px = px, py = py);
+    let _enter = span.enter();
+
+    let pixel_in_space = translate_pixel(px, py);
+
+    let ray_start = if scene.parallel_projection {
+      // For a parallel projection, we'll just take the view direction and
+      // subtract it from the target point. This means every single
+      // ray will be viewed from a point at infinity, rather than a single eye
+      // position.
+      let n = scene.view_dir.normalize();
+      let view_dir = n * distance;
+      pixel_in_space - view_dir
+    } else {
+      scene.eye_pos
+    };
+
+    let ray = Ray::from_endpoints(ray_start, pixel_in_space);
+
+    // let res= rayon::spawn(|| scene.trace_single_ray(ray, 0));
+    scene.trace_single_ray(scene.eye_pos, ray, 0)
+  };
+
+  // For debugging purposes!
+  if let Some(RenderPixel(px, py)) = opt.render_pixel {
+    let pixel_color = evaluate_at_pixel(px, py)?;
+    println!("Pixel color: {pixel_color}");
+    return Ok(());
+  }
+
   // Generate a parallel iterator for pixels
   // The iterator preserves order and uses row-major order
   let pixels_iter = (0..scene.image_height)
@@ -89,29 +117,7 @@ fn main() -> Result<()> {
 
   // Loop through every single pixel of the output file
   let pixels = pixels_iter
-    .map(|(px, py)| {
-      let span = trace_span!("main_loop", px = px, py = py);
-      let _enter = span.enter();
-
-      let pixel_in_space = translate_pixel(px, py);
-
-      let ray_start = if scene.parallel_projection {
-        // For a parallel projection, we'll just take the view direction and
-        // subtract it from the target point. This means every single
-        // ray will be viewed from a point at infinity, rather than a single eye
-        // position.
-        let n = scene.view_dir.normalize();
-        let view_dir = n * distance;
-        pixel_in_space - view_dir
-      } else {
-        scene.eye_pos
-      };
-
-      let ray = Ray::from_endpoints(ray_start, pixel_in_space);
-
-      // let res= rayon::spawn(|| scene.trace_single_ray(ray, 0));
-      scene.trace_single_ray(scene.eye_pos, ray, 0)
-    })
+    .map(|(px, py)| evaluate_at_pixel(px, py))
     .collect::<Result<Vec<_>>>()?;
 
   // Construct and emit image
@@ -128,3 +134,71 @@ fn main() -> Result<()> {
 
   Ok(())
 }
+
+#[derive(Clone)]
+struct RenderPixel(usize, usize);
+
+impl FromStr for RenderPixel {
+  type Err = anyhow::Error;
+
+  fn from_str(s: &str) -> Result<Self, Self::Err> {
+    let parts = s.split(",").collect::<Vec<_>>();
+    ensure!(parts.len() == 2, "must be a pair");
+
+    let x = parts[0].parse::<usize>()?;
+    let y = parts[1].parse::<usize>()?;
+
+    Ok(RenderPixel(x, y))
+  }
+}
+
+/// A little bit of engineering to make it easy to write conditional builders
+/// for logging setup because the tracing-subscriber crate for some reason
+/// decided it would be a good idea to have all of its builders be polymorphic?
+macro_rules! logsetup_if {
+  ($ident:ident , $cond:expr , $iftrue:expr , $iffalse:expr => { $($body:tt)* }) => {
+    if ($cond) {
+      let $ident = $iftrue;
+      $($body)*
+    } else {
+      let $ident = $iffalse;
+      $($body)*
+    }
+  };
+}
+
+fn setup_logging(opt: &Opt) -> Option<WorkerGuard> {
+  let mut result = None;
+
+  let level_filter = match opt.verbosity {
+    0 => LevelFilter::ERROR,
+    1 => LevelFilter::WARN,
+    2 => LevelFilter::INFO,
+    3 => LevelFilter::DEBUG,
+    _ => LevelFilter::TRACE,
+  };
+
+  let layer = Layer::default();
+
+  logsetup_if! (layer, opt.use_json, layer.json(), layer => {
+    let layer = layer
+      .with_target(false)
+      .with_timer(tracing_subscriber::fmt::time::uptime())
+      .with_level(true);
+
+    logsetup_if! (layer, opt.log_output.is_some(), {
+      let log_output = opt.log_output.clone().unwrap();
+      let file_appender = tracing_appender::rolling::never(".", log_output);
+      let (non_blocking, guard) = tracing_appender::non_blocking(file_appender);
+      result = Some(guard);
+      layer.with_writer(non_blocking)
+    }, layer => {
+      tracing_subscriber::registry()
+        .with(layer)
+        .with(level_filter)
+        .init();
+    });
+  });
+
+  result
+}

assignment-1d/src/ray.rs

@@ -1,15 +1,34 @@
+use std::fmt;
+
 use crate::{Point, Vector};
 
 /// A normalized parametric Ray of the form (origin + direction * time)
 ///
 /// That means at any time t: f64, the point represented by origin + direction *
-/// time occurs on the ray.
-#[derive(Debug)]
+/// time occurs on the ray. This is pretty much a (time -> point) function.
 pub struct Ray {
+  /// The point in space where the ray started
   pub origin: Point,
+
+  /// The direction the ray is headed
   pub direction: Vector,
 }
 
+impl fmt::Debug for Ray {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+    write!(
+      f,
+      "({:.2}, {:.2}, {:.2}) + t * ({:.2}, {:.2}, {:.2})",
+      self.origin.x,
+      self.origin.y,
+      self.origin.z,
+      self.direction.x,
+      self.direction.y,
+      self.direction.z,
+    )
+  }
+}
+
 impl Ray {
   pub fn new(origin: Point, direction: Vector) -> Self {
     Ray { origin, direction }

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

@@ -11,7 +11,9 @@ use rayon::prelude::{
 use crate::{
   image::Color,
   ray::Ray,
-  utils::{compute_refraction_lengths, dot, RefractionResult},
+  utils::{
+    compute_reflection_ray, compute_refraction_lengths, dot, RefractionResult,
+  },
   Point, Vector,
 };
 
@@ -48,8 +50,7 @@ impl Scene {
     intersection_context: IntersectionContext,
     depth: usize,
   ) -> Result<Color> {
-    let span =
-      trace_span!("compute_pixel_color", intersection = ?intersection_context);
+    let span = trace_span!("compute_pixel_color", intersection = ?intersection_context, incident_ray=?incident_ray);
     let _enter = span.enter();
 
     let material = match self.materials.get(object.material_idx) {
@@ -83,17 +84,7 @@ impl Scene {
         // The vector pointing in the direction of the light
         let light_direction = light.direction_from(intersection_context.point);
 
-        let normal = {
-          let mut normal = intersection_context.normal.normalize();
-
-          // If we're exiting the material, the normal should face the other direction since that's
-          // how the reflection works
-          if intersection_context.exiting {
-            normal = -normal;
-          }
-
-          normal
-        };
+        let normal = intersection_context.normal.normalize(); // reflection_normal();
 
         // Viewer direction is no longer towards the eye, but to the last origin point, so that
         // transmitted rays reflect properly
@@ -147,30 +138,6 @@ impl Scene {
       })
       .sum();
 
-    /*
-    let specular_reflection: Color = {
-      let reflection_ray = self.compute_reflection_ray(
-        incident_ray.direction,
-        intersection_context.normal,
-      );
-
-      let fresnel_coefficient = self.compute_fresnel_coefficient(
-        &material,
-        incident_ray.direction,
-        intersection_context.normal,
-      );
-
-      // Jitter a bit to reduce acne
-      let origin = intersection_context.point;
-      let origin = origin + JITTER_CONST * reflection_ray;
-
-      let ray = Ray::new(origin, reflection_ray);
-      let r_lambda = self.trace_single_ray(origin, ray, depth + 1)?;
-
-      fresnel_coefficient * r_lambda
-    };
-      */
-
     let (eta_i, eta_t) = match intersection_context.exiting {
       // true => (material.eta, 1.0),
       _ => (1.0, material.eta),
@@ -186,7 +153,7 @@ impl Scene {
       )?
     };
 
-    let transparency_component = if eta_t < 1.0 {
+    let transparency_component = if eta_t < 1.0 || material.alpha == 1.0 {
       ZERO_COLOR
     } else {
       self.compute_transparency(
@@ -212,6 +179,14 @@ impl Scene {
           * (1.0 - material.alpha)
           * transparency_component
     };
+    debug!(
+      last_time_component = ?(ambient_component + diffuse_and_specular),
+      ?specular_reflection_component,
+      ?transparency_component,
+      ?fresnel_coefficient,
+      ?color,
+      "color result"
+    );
 
     // Apply depth cueing to the result
     let a_dc = {
@@ -412,30 +387,15 @@ impl Scene {
     fr
   }
 
-  fn compute_reflection_ray(
-    &self,
-    incident_ray: Vector,
-    normal: Vector,
-  ) -> Vector {
-    let opposite_incident_ray = (-incident_ray).normalize();
-    let unit_normal = normal.normalize();
-
-    let a = dot(unit_normal, opposite_incident_ray);
-    let r = 2.0 * (a * unit_normal) - opposite_incident_ray;
-
-    r
-  }
-
   fn compute_specular_reflection(
     &self,
     intersection_context: &IntersectionContext,
     incident_ray: &Ray,
     depth: usize,
   ) -> Result<Color> {
-    // Specular reflection
-    let reflection_ray = self.compute_reflection_ray(
+    let reflection_ray = compute_reflection_ray(
       incident_ray.direction.clone(),
-      intersection_context.normal,
+      intersection_context.reflection_normal().normalize(),
     );
 
     let origin = intersection_context.point;
@@ -458,14 +418,7 @@ impl Scene {
     let _enter = span.enter();
 
     // Fix the normal direction to account for exiting a material
-    let normal = {
-      let mut n = intersection_context.normal.normalize();
-      if intersection_context.exiting {
-        n = -n;
-      }
-
-      n
-    };
+    let normal = intersection_context.reflection_normal().normalize();
 
     let i = incident_ray.direction.normalize();
 
@@ -484,7 +437,7 @@ impl Scene {
       match compute_refraction_lengths(normal, &incident_ray, eta_i, eta_t) {
         Some(RefractionResult {
           cos_theta_i,
-          sin_theta_i,
+          sin_theta_i: _,
           sin_theta_t,
           cos_theta_t,
         }) => {
@@ -493,7 +446,7 @@ impl Scene {
           // new direction.
 
           // Calculate refraction direction
-          let a = normal.normalize() * cos_theta_t;
+          let a = normal * cos_theta_t;
           let s_direction = cos_theta_i * normal - i;
           let m_unit = s_direction.normalize();
           let b = m_unit * sin_theta_t;
@@ -550,4 +503,13 @@ pub struct IntersectionContext {
 
 impl Eq for IntersectionContext {}
 
-impl IntersectionContext {}
+impl IntersectionContext {
+  // If we're exiting the material, the normal should face the other direction
+  // since that's how the reflection works
+  pub fn reflection_normal(&self) -> Vector {
+    match self.exiting {
+      true => -self.normal,
+      false => self.normal,
+    }
+  }
+}

assignment-1d/src/scene/tracing.rs

@@ -44,6 +44,8 @@ impl Scene {
     let earliest_intersection =
       intersections.into_iter().min_by_key(|(_, t, _)| t.time);
 
+    info!("Ray {ray:?} intersected at: {earliest_intersection:?}");
+
     Ok(match earliest_intersection {
       // Take the object's material color
       Some((obj_idx, intersection_context, object)) => self

assignment-1d/src/scene/triangle.rs

@@ -61,6 +61,11 @@ impl Triangle {
       -(a * x0 + b * y0 + c * z0 + d) / denom
     };
 
+    // Intersected the plane behind where the ray started
+    if time < 0.0 {
+      return Ok(None);
+    }
+
     let time = NotNan::new(time)?;
     let point = ray.eval(*time);
 

assignment-1d/src/utils.rs

@@ -134,3 +134,27 @@ pub fn compute_refraction_lengths(
     cos_theta_t,
   })
 }
+
+#[allow(non_snake_case)]
+pub fn compute_reflection_ray(incident_ray: Vector, normal: Vector) -> Vector {
+  let I = (-incident_ray).normalize();
+  let N = normal.normalize();
+
+  2.0 * dot(N, I) * N - I
+}
+
+#[cfg(test)]
+mod tests {
+  use crate::{utils::compute_reflection_ray, Vector};
+
+  #[test]
+  fn test_reflection_ray() {
+    let incident_ray = Vector::new(2.0, -1.0, 2.0);
+    let normal = Vector::new(0.0, 1.0, 0.0);
+
+    assert_eq!(
+      compute_reflection_ray(incident_ray, normal),
+      Vector::new(2.0, 1.0, 2.0).normalize()
+    );
+  }
+}