diffuse path tracing

Cargo.toml

@@ -11,4 +11,5 @@ clap = { version = "4.4.8", features = ["derive"] }
 cgmath = "0.18.0"
 rayon = "1.8.0"
 image = "0.24.7"
-rand = "0.8.5"
+rand = "0.8.5"
+indicatif = { version = "0.17.7", features = ["rayon"] }

src/colors.rs

@@ -48,8 +48,7 @@ pub fn normalize_colors_global(radiosity_buffer: &mut Vec<Vec<Vector4<f32>>>) ->
     });
 
     //calculate difference between min and max pixel radiosity
-    //TODO: drop upper 20 percent of radiosity to illiminate outliers
-    let range = (maximum_radiosity * 0.8) - minimum_radiosity;
+    let range = maximum_radiosity - minimum_radiosity;
     //normalize to range
     for column in &mut *radiosity_buffer {
         for radiosity_value in column {

src/main.rs

@@ -49,6 +49,7 @@ fn main() {
         &args.gltf_file_path)
         .expect(&*format!("Failed to load glTF file {}", &args.gltf_file_path));
 
+    println!("Path tracing image. Columns finished:");
     let mut radiosity_buffer: Vec<Vec<Vector4<f32>>> = match render(scenes, &args).lock() {
         Ok(buffer) => {buffer.to_vec()}
         Err(_) => {panic!("Unable to lock radiosity buffer!")}
@@ -64,6 +65,6 @@ fn main() {
     let output_image =
         store_colors_to_image(as_colors);
 
-    output_image.save("result_image.png").expect("Unable to save image!");
+    output_image.save("../output_image.png").expect("Unable to save image!");
 }
 

src/renderer.rs

@@ -1,11 +1,13 @@
+use indicatif::ProgressIterator;
 use std::f32::consts::PI;
 use std::ops::{Add, Mul};
-use std::sync::{Arc, LockResult, Mutex};
+use std::sync::{Arc, Mutex};
 use cgmath::{Angle, ElementWise, InnerSpace, Matrix4, Vector2, Vector3, Vector4};
+use cgmath::num_traits::abs;
 use rayon::iter::{IntoParallelIterator, ParallelIterator};
 use easy_gltf::model::{Mode};
 use easy_gltf::{Camera, Projection, Scene};
-use rayon::prelude::IntoParallelRefIterator;
+use indicatif::ParallelProgressIterator;
 use crate::Args;
 use crate::geometry::{Intersectable};
 use crate::ray::{construct_primary_rays, Ray};
@@ -51,36 +53,38 @@ pub fn render(scenes: &Vec<Scene>,
     });
 
     //iterate over all pixels in the image
-    (0..cl_args.width).into_par_iter().for_each(|px| {
-        (0..cl_args.height).into_par_iter().for_each(|py| {
-            //construct all rays
-            let rays: Vec<Ray> = construct_primary_rays(
-                (cl_args.width, cl_args.height),
-                (px, py),
-                &transform_matrix,
-                z,
-                cl_args.multiplier,
-            );
-
-            //let the initial pixel color be black and opaque
-            let mut pixel_radiosity: Vector4<f32> = Vector4::new(0.0, 0.0, 0.0, 1.0);
-
-            //cast each ray and get the output luminosity and sum them up
-            rays.iter().for_each(|ray| {
-                pixel_radiosity = pixel_radiosity.add(
-                    raytrace(&ray, render_scene, cl_args.recurse)
+    (0..cl_args.width).into_par_iter()
+        .progress_count(cl_args.width as u64)
+        .for_each(|px| {
+            (0..cl_args.height).into_par_iter().for_each(|py| {
+                //construct all rays
+                let rays: Vec<Ray> = construct_primary_rays(
+                    (cl_args.width, cl_args.height),
+                    (px, py),
+                    &transform_matrix,
+                    z,
+                    cl_args.multiplier,
                 );
-            });
 
-            //store radiosity into the buffer
-            match radiosity_buffer.clone().lock() {
-                Ok(mut buffer) => {
-                    buffer[px][py] = pixel_radiosity;
+                //let the initial pixel color be black and opaque
+                let mut pixel_radiosity: Vector4<f32> = Vector4::new(0.0, 0.0, 0.0, 1.0);
+
+                //cast each ray and get the output luminosity and sum them up
+                rays.iter().for_each(|ray| {
+                    pixel_radiosity = pixel_radiosity.add(
+                        raytrace(&ray, render_scene, cl_args.recurse)
+                    );
+                });
+
+                //store radiosity into the buffer
+                match radiosity_buffer.clone().lock() {
+                    Ok(mut buffer) => {
+                        buffer[px][py] = pixel_radiosity;
+                    }
+                    Err(_) => { panic!("Unable to lock pixel buffer!") }
                 }
-                Err(_) => { panic!("Unable to lock pixel buffer!") }
-            }
+            });
         });
-    });
     radiosity_buffer
 }
 
@@ -121,6 +125,7 @@ fn raytrace(ray: &Ray, scene: &Scene, recursion_depth_left: usize) -> Vector4<f3
                                     isec,
                                     model.material(),
                                     triangle.clone(),
+                                    ray,
                                 )
                             );
                     }
@@ -161,27 +166,31 @@ fn accumulate_colors(intersection_data: &IntersectionData,
     let intersected_triangle = intersection_data.intersected_triangle();
     let tangent = (intersected_triangle[0].position -
         intersected_triangle[1].position).normalize();
-    let face_normal: Vector3<f32> = tangent
+    let mut face_normal: Vector3<f32> = tangent
         .cross(intersected_triangle[0].position -
             intersected_triangle[2].position).normalize();
-    let bitangent = tangent.cross(face_normal);
+    //flip normal if face is hit from behind
+    if face_normal.dot(-intersection_data.ray().direction) < 0.0 {
+        face_normal *= -1.0;
+    }
+    let bitangent = tangent.cross(face_normal).normalize();
 
     /*
     generate random direction on hemisphere
      */
     let phi = rand::random::<f32>() * 2.0 * PI;
     //allow arbitrary angles
-    let theta = rand::random::<f32>() * 2.0 * PI;
+    let radius = rand::random::<f32>();
+    let sqrt_radius = f32::sqrt(rand::random::<f32>());
 
-    let sin_theta = f32::sin(theta);
-    let direction = tangent * f32::cos(phi) * sin_theta +
-        bitangent * f32::sin(phi) * sin_theta +
-        face_normal * f32::cos(theta);
+    let direction = (tangent * f32::cos(phi) * sqrt_radius +
+        bitangent * f32::sin(phi) * sqrt_radius +
+        face_normal * f32::sqrt(1.0 - radius)).normalize();
 
     let secondary_ray = Ray {
         //prevent self-intersection
         source: intersection_data.intersection_point() + RAY_EPSILON * face_normal,
-        direction: direction.normalize(),
+        direction,
     };
 
     //path trace recursively
@@ -193,10 +202,8 @@ fn accumulate_colors(intersection_data: &IntersectionData,
 
     let cos_weighting = direction.dot(face_normal);
 
-    //make ray contribution decay exponentially
     let brdf = intersection_data.material()
-        .get_base_color_alpha(Vector2::new(0.0, 0.0))
-        * (1.0 - f32::powf(6.0, -0.5 * recursion_depth_left as f32));
+        .get_base_color_alpha(Vector2::new(0.0, 0.0));
 
     //reflected component
     pixel_radiosity += brdf.mul_element_wise(incoming_radiosity) * cos_weighting * 2.0 * PI;

src/scene_data.rs

@@ -2,22 +2,26 @@ use std::sync::Arc;
 use cgmath::Vector3;
 use easy_gltf::{Material};
 use easy_gltf::model::Triangle;
+use crate::ray::Ray;
 
-pub(crate) struct IntersectionData {
+pub(crate) struct IntersectionData<'a> {
     intersection_point: Vector3<f32>,
     material: Arc<Material>,
     intersected_triangle: Triangle,
+    ray: &'a Ray,
 }
 
-impl IntersectionData {
+impl IntersectionData<'_>{
     pub fn new(
         intersection_point: Vector3<f32>,
         material: Arc<Material>,
-        intersected_triangle: Triangle) -> IntersectionData {
+        intersected_triangle: Triangle,
+        ray: &Ray) -> IntersectionData {
         IntersectionData {
             intersection_point,
             material,
             intersected_triangle,
+            ray,
         }
     }
 
@@ -32,4 +36,8 @@ impl IntersectionData {
     pub fn intersected_triangle(&self) -> Triangle {
         self.intersected_triangle
     }
+
+    pub fn ray(&self) -> &Ray {
+        self.ray
+    }
 }