reflection directly along normal

src/main.rs

@@ -37,6 +37,9 @@ pub struct Args {
     ///start in debug mode (e.g. without parallelization)
     #[arg(long)]
     debug: bool,
+    ///path tracing recursion depth
+    #[arg(long)]
+    recurse: usize
 }
 
 fn main() {

src/renderer.rs

@@ -1,6 +1,6 @@
 use std::ops::{Add, Mul};
 use std::sync::{Arc, LockResult, Mutex};
-use cgmath::{Angle, ElementWise, Matrix4, Vector2, Vector3, Vector4};
+use cgmath::{Angle, ElementWise, InnerSpace, Matrix4, Vector2, Vector3, Vector4};
 use rayon::iter::{IntoParallelIterator, ParallelIterator};
 use easy_gltf::model::{Mode};
 use easy_gltf::{Camera, Material, Projection, Scene};
@@ -9,6 +9,8 @@ use crate::geometry::{Intersectable};
 use crate::ray::{construct_primary_rays, Ray};
 use crate::scene_data::IntersectionData;
 
+const RAY_EPSILON: f32 = 0.0007;
+
 pub fn render(scenes: &Vec<Scene>,
               cl_args: &Args) -> Arc<Mutex<Vec<Vec<Vector4<f32>>>>> {
     let render_scene: &Scene = &scenes[cl_args.scene_index];
@@ -38,13 +40,17 @@ pub fn render(scenes: &Vec<Scene>,
         Arc::new(Mutex::new(Vec::with_capacity(cl_args.width)));
 
     //prepare the radiosity buffer
-    (0..cl_args.height).into_iter().for_each(|py| {
-        radiosity_buffer.lock().unwrap().push(Vec::with_capacity(cl_args.height))
+    (0..cl_args.width).into_iter().for_each(|px| {
+        let mut empty_vector = Vec::with_capacity(cl_args.height);
+        for _ in 0..cl_args.height {
+            empty_vector.push(Vector4::new(0.0, 0.0, 0.0, 0.0));
+        }
+        radiosity_buffer.lock().unwrap().push(empty_vector);
     });
 
     //iterate over all pixels in the image
-    (0..cl_args.width).into_iter().for_each(|px| {
-        (0..cl_args.height).into_iter().for_each(|py| {
+    (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),
@@ -60,27 +66,28 @@ pub fn render(scenes: &Vec<Scene>,
             //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, 4)
+                    raytrace(ray, render_scene, cl_args.recurse)
                 );
             });
 
             //store radiosity into the buffer
             match radiosity_buffer.clone().lock() {
                 Ok(mut buffer) => {
-                    buffer[px].push(pixel_radiosity);
+                    buffer[px][py] = pixel_radiosity;
                 }
                 Err(_) => { panic!("Unable to lock pixel buffer!") }
             }
-
         });
     });
     radiosity_buffer
 }
 
 
-fn raytrace(ray: &Ray, scene: &Scene, recursion_depth: u32) -> Vector4<f32> {
-    let mut pixel_radiosity: Vector4<f32> = Vector4::new(0.0, 0.0, 0.0, 255.0);
+fn raytrace(ray: &Ray, scene: &Scene, recursion_depth_left: usize) -> Vector4<f32> {
+    let mut pixel_radiosity: Vector4<f32> = Vector4::new(0.0, 0.0, 0.0, 1.0);
 
+    //abort if no recursion steps are left
+    if recursion_depth_left == 0 { return pixel_radiosity; }
 
     let mut smallest_t: f32 = f32::MAX;
     let mut intersection_data: Option<IntersectionData> = None;
@@ -100,8 +107,8 @@ fn raytrace(ray: &Ray, scene: &Scene, recursion_depth: u32) -> Vector4<f32> {
         //iterate all triangles in a model
         triangles.iter().for_each(|triangle| {
             match triangle.test_isec(&ray) {
-                //boilerplate implementation to set pixel to red if any intersection happened
                 None => {}
+                //set data if intersection has been detected
                 Some((t, isec)) => {
                     // a new closer Point is found
                     if t < smallest_t {
@@ -110,7 +117,9 @@ fn raytrace(ray: &Ray, scene: &Scene, recursion_depth: u32) -> Vector4<f32> {
                             Option::from(
                                 IntersectionData::new(
                                     isec,
-                                    model.material())
+                                    model.material(),
+                                    triangle.clone(),
+                                )
                             );
                     }
                 }
@@ -120,8 +129,9 @@ fn raytrace(ray: &Ray, scene: &Scene, recursion_depth: u32) -> Vector4<f32> {
 
     match intersection_data {
         Some(isec_data) => {
-            pixel_radiosity = accumulate_colors(isec_data.intersection_point(),
-                                                isec_data.material());
+            pixel_radiosity = accumulate_colors(&isec_data,
+                                                &scene,
+                                                recursion_depth_left);
         }
         None {} => {}
     }
@@ -130,19 +140,38 @@ fn raytrace(ray: &Ray, scene: &Scene, recursion_depth: u32) -> Vector4<f32> {
 }
 
 /// called iff an intersection is detected to (recursively) accumulate radiosity at intersection
-fn accumulate_colors(_intersection_point: Vector3<f32>, isec_material: &Arc<Material>) -> Vector4<f32> {
+fn accumulate_colors(intersection_data: &IntersectionData,
+                     global_scene: &Scene,
+                     recursion_depth_left: usize) -> Vector4<f32> {
     let mut pixel_radiosity: Vector4<f32>
         = Vector4::new(0.0, 0.0, 0.0, 1.0);
     //accumulate colors at point
-    //emmisive Component
+    //emissive Component
     pixel_radiosity +=
-        isec_material.emissive.factor.extend(1.0)
+        intersection_data.material().emissive.factor.extend(1.0)
             .mul_element_wise(
-                isec_material.get_base_color_alpha(Vector2::new(0.0, 0.0))
+                intersection_data.material()
+                    .get_base_color_alpha(Vector2::new(0.0, 0.0))
             );
 
+    //get the intersected triangle and calculate the face normals
+    let intersected_triangle = intersection_data.intersected_triangle();
+    let face_normal: Vector3<f32> = (intersected_triangle[0].position - intersected_triangle[1].position)
+        .cross(intersected_triangle[0].position - intersected_triangle[2].position).normalize();
 
-    //TODO: Path tracing. Scatter ray in one random direction
+    let secondary_ray = Ray {
+        //prevent self-intersection
+        source: intersection_data.intersection_point() + RAY_EPSILON * face_normal,
+        direction: face_normal,
+    };
+
+    let incoming_radiosity = raytrace(
+        &secondary_ray,
+        global_scene,
+        recursion_depth_left - 1);
+
+    //reflected component
+    pixel_radiosity += incoming_radiosity * 0.2;
 
     pixel_radiosity
 }

src/scene_data.rs

@@ -1,17 +1,23 @@
 use std::sync::Arc;
 use cgmath::Vector3;
-use easy_gltf::Material;
+use easy_gltf::{Material, Scene};
+use easy_gltf::model::Triangle;
 
 pub(crate) struct IntersectionData {
     intersection_point: Vector3<f32>,
-    material: Arc<Material>
+    material: Arc<Material>,
+    intersected_triangle: Triangle,
 }
 
 impl IntersectionData {
-    pub fn new(intersection_point: Vector3<f32>, material: Arc<Material>) -> IntersectionData{
+    pub fn new(
+        intersection_point: Vector3<f32>,
+        material: Arc<Material>,
+        intersected_triangle: Triangle) -> IntersectionData {
         IntersectionData {
             intersection_point,
             material,
+            intersected_triangle,
         }
     }
 
@@ -22,4 +28,8 @@ impl IntersectionData{
     pub fn material(&self) -> &Arc<Material> {
         &self.material
     }
+
+    pub fn intersected_triangle(&self) -> Triangle {
+        self.intersected_triangle
+    }
 }