Use BoundingVolumeHierarchy to accelerate rendering

src/main.rs

@@ -19,7 +19,7 @@ use vanrijn::colour::{ColourRgbF, NamedColour};
 use vanrijn::image::{ClampingToneMapper, ImageRgbU8, ToneMapper};
 use vanrijn::materials::{LambertianMaterial, PhongMaterial, ReflectiveMaterial};
 use vanrijn::mesh::load_obj;
-use vanrijn::raycasting::{Plane, Primitive, Sphere};
+use vanrijn::raycasting::{BoundingVolumeHierarchy, Plane, Primitive, Sphere};
 use vanrijn::scene::Scene;
 use vanrijn::util::{Tile, TileIterator};
 
@@ -70,18 +70,7 @@ pub fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     let scene = Arc::new(Scene {
         camera_location: Point3::new(-2.0, 1.0, -5.0),
-        objects: load_obj(
-            Path::new("/home/matthew/Downloads/bunny.obj"),
-            Arc::new(ReflectiveMaterial {
-                colour: ColourRgbF::from_named(NamedColour::Yellow),
-                diffuse_strength: 0.05,
-                reflection_strength: 0.9,
-            }),
-        )
-        .unwrap()
-        .into_iter()
-        .map(|triangle| Arc::new(triangle) as Arc<dyn Primitive<f64>>)
-        .chain(vec![
+        objects: vec![
             Arc::new(Plane::new(
                 Vector3::new(0.0, 1.0, 0.0),
                 -2.0,
@@ -117,8 +106,18 @@ pub fn main() -> Result<(), Box<dyn std::error::Error>> {
                     specular_strength: 1.0,
                 }),
             )),
-        ])
-        .collect(),
+            Arc::new(BoundingVolumeHierarchy::build(
+                &load_obj(
+                    Path::new("/home/matthew/Downloads/bunny.obj"),
+                    Arc::new(ReflectiveMaterial {
+                        colour: ColourRgbF::from_named(NamedColour::Yellow),
+                        diffuse_strength: 0.05,
+                        reflection_strength: 0.9,
+                    }),
+                )
+                .unwrap(),
+            )),
+        ],
     });
 
     let mut event_pump = sdl_context.event_pump()?;
@@ -127,7 +126,7 @@ pub fn main() -> Result<(), Box<dyn std::error::Error>> {
     let mut tile_rx = Some(tile_rx);
 
     let worker_boss = std::thread::spawn(move || {
-        TileIterator::new(image_width as usize, image_height as usize, 8)
+        TileIterator::new(image_width as usize, image_height as usize, 32)
             .map(move |tile| (tile, tile_tx.clone()))
             .par_bridge()
             .try_for_each(|(tile, tx)| {

src/mesh.rs

@@ -2,7 +2,7 @@ mod wavefront_obj {
     use crate::materials::Material;
     use crate::Real;
 
-    use crate::raycasting::Triangle;
+    use crate::raycasting::{Primitive, Triangle};
 
     use alga::general::SupersetOf;
     use nalgebra::{convert, Point3, Vector3};
@@ -67,7 +67,7 @@ mod wavefront_obj {
     pub fn load_obj<T: Real>(
         filename: &Path,
         material: Arc<dyn Material<T>>,
-    ) -> Result<Vec<Triangle<T>>>
+    ) -> Result<Vec<Arc<dyn Primitive<T>>>>
     where
         T: SupersetOf<f32>,
     {
@@ -79,6 +79,7 @@ mod wavefront_obj {
             .flat_map(|object| object.groups.iter())
             .flat_map(|group| group.polys.iter())
             .flat_map(|poly| get_triangles(poly, &obj.position, &obj.normal, material.clone()))
+            .map(|triangle| Arc::new(triangle) as Arc<dyn Primitive<T>>)
             .collect())
     }
 }

src/raycasting/bounding_volume_hierarchy.rs

@@ -1,4 +1,4 @@
-use super::{BoundingBox, Primitive};
+use super::{BoundingBox, HasBoundingBox, Intersect, IntersectP, IntersectionInfo, Primitive, Ray};
 
 use crate::util::morton::morton_order_value_3d;
 use crate::util::normalizer::Point3Normalizer;
@@ -111,6 +111,55 @@ impl<T: Real> BoundingVolumeHierarchy<T> {
     }
 }
 
+fn closest_intersection<T: Real>(
+    a: Option<IntersectionInfo<T>>,
+    b: Option<IntersectionInfo<T>>,
+) -> Option<IntersectionInfo<T>> {
+    match (a, b) {
+        (Some(a), Some(b)) => {
+            if a.distance < b.distance {
+                Some(a)
+            } else {
+                Some(b)
+            }
+        }
+        (Some(a), None) => Some(a),
+        (None, Some(b)) => Some(b),
+        (None, None) => None,
+    }
+}
+
+impl<T: Real> Intersect<T> for BoundingVolumeHierarchy<T> {
+    fn intersect<'a>(&'a self, ray: &Ray<T>) -> Option<IntersectionInfo<T>> {
+        match self {
+            Self::Node {
+                bounds,
+                left,
+                right,
+            } => {
+                if bounds.intersect(ray) {
+                    closest_intersection(left.intersect(ray), right.intersect(ray))
+                } else {
+                    None
+                }
+            }
+            Self::Leaf {
+                bounds: _,
+                primitive,
+            } => primitive.intersect(ray),
+            Self::None => None,
+        }
+    }
+}
+
+impl<T: Real> HasBoundingBox<T> for BoundingVolumeHierarchy<T> {
+    fn bounding_box(&self) -> BoundingBox<T> {
+        self.get_bounds()
+    }
+}
+
+impl<T: Real> Primitive<T> for BoundingVolumeHierarchy<T> {}
+
 pub struct FilterIterator<'a, T: Real> {
     unsearched_subtrees: Vec<&'a BoundingVolumeHierarchy<T>>,
     predicate: Box<dyn Fn(&BoundingBox<T>) -> bool>,

src/raycasting/mod.rs

@@ -18,6 +18,7 @@ pub mod axis_aligned_bounding_box;
 pub use axis_aligned_bounding_box::BoundingBox;
 
 pub mod bounding_volume_hierarchy;
+pub use bounding_volume_hierarchy::BoundingVolumeHierarchy;
 
 #[derive(Clone, Debug)]
 pub struct Ray<T: Real> {