Draw first image

.gitignore

@@ -1 +1,2 @@
 .target
+**.exr

Cargo.toml

@@ -1,4 +1,4 @@
 [workspace]
 
-members = [ "ray-tracing-core"]
+members = [ "ray-tracing-core", "ray-tracing-image", "ray-tracing-scene"]
 resolver = "2"

ray-tracing-core/Cargo.toml

@@ -4,3 +4,4 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+rand = "0.8.5"

ray-tracing-core/src/camera.rs

@@ -0,0 +1,74 @@
+use crate::prelude::*;
+use rand::Rng;
+
+pub trait Camera<R: Rng> {
+    fn forward(&self, x: u32, y: u32, rng: &mut R) -> Ray;
+    fn width(&self) -> u32;
+    fn height(&self) -> u32;
+}
+
+pub struct BasicCamera {
+    width: u32,
+    height: u32,
+    pos: Pos3,
+    dir: Dir3,
+    h: Dir3,
+    v: Dir3,
+}
+
+impl BasicCamera {
+    pub fn new(
+        width: u32,
+        height: u32,
+        pos: Pos3,
+        dir: Dir3,
+        up: Dir3,
+        horizontal_fov: Float,
+    ) -> Self {
+        assert!(horizontal_fov < FloatConsts::PI);
+        let dir = dir.normalize();
+        let up = up.normalize();
+        let l = Float::sin(0.5 * horizontal_fov);
+        let h = l * Dir3::cross(dir, up);
+        let v = l * ((height as Float) / (width as Float)) * Dir3::cross(dir, h.normalize());
+        Self {
+            width,
+            height,
+            pos,
+            dir,
+            h,
+            v,
+        }
+    }
+
+    pub fn from_look_at(
+        width: u32,
+        height: u32,
+        pos: Pos3,
+        look_at: Pos3,
+        up: Dir3,
+        horizontal_fov: Float,
+    ) -> Self {
+        Self::new(width, height, pos, look_at - pos, up, horizontal_fov)
+    }
+}
+
+impl<R: Rng> Camera<R> for BasicCamera {
+    fn forward(&self, x: u32, y: u32, rng: &mut R) -> Ray {
+        // normalize x and y to -0.5 to 0.5
+        let x = ((x as Float + rng.gen::<Float>()) / (self.width as Float)) - 0.5;
+        let y = ((y as Float + rng.gen::<Float>()) / (self.height as Float)) - 0.5;
+
+        let dir = self.dir + x * self.h + y * self.v;
+
+        Ray::new(self.pos, dir.normalize(), 0.0)
+    }
+
+    fn width(&self) -> u32 {
+        self.width
+    }
+
+    fn height(&self) -> u32 {
+        self.height
+    }
+}

ray-tracing-core/src/color.rs

@@ -0,0 +1,67 @@
+use crate::prelude::*;
+use std::ops::{Add, AddAssign, Div};
+
+#[derive(Debug, Clone, Copy)]
+pub struct Color {
+    r: Float,
+    g: Float,
+    b: Float,
+}
+
+impl Color {
+    pub fn new(r: Float, g: Float, b: Float) -> Self {
+        Self { r, g, b }
+    }
+
+    pub fn r(self) -> Float {
+        self.r
+    }
+
+    pub fn g(self) -> Float {
+        self.g
+    }
+
+    pub fn b(self) -> Float {
+        self.b
+    }
+
+    pub fn gray(x: Float) -> Self {
+        Self::new(x, x, x)
+    }
+
+    pub fn black() -> Self {
+        Self::gray(0.0)
+    }
+}
+
+impl Add for Color {
+    type Output = Color;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        Self {
+            r: self.r + rhs.r,
+            g: self.g + rhs.g,
+            b: self.b + rhs.b,
+        }
+    }
+}
+
+impl AddAssign for Color {
+    fn add_assign(&mut self, rhs: Self) {
+        self.r += rhs.r;
+        self.g += rhs.g;
+        self.b += rhs.b;
+    }
+}
+
+impl Div<Float> for Color {
+    type Output = Color;
+
+    fn div(self, rhs: Float) -> Self::Output {
+        Self {
+            r: self.r / rhs,
+            g: self.g / rhs,
+            b: self.b / rhs,
+        }
+    }
+}

ray-tracing-core/src/lib.rs

@@ -1,11 +1,16 @@
+pub mod camera;
+pub mod color;
 pub mod material;
 pub mod math;
 pub mod ray;
+pub mod renderer;
 pub mod scene;
 
 pub mod prelude {
-    pub type Float = f64;
+    pub type Float = f32;
+    pub use crate::color::Color;
     pub use crate::material::Material;
-    pub use crate::math::{Dir3, Pos3};
+    pub use crate::math::*;
     pub use crate::ray::Ray;
+    pub use std::f32::consts as FloatConsts;
 }

ray-tracing-core/src/material.rs

@@ -1 +1,15 @@
-pub trait Material {}
+use crate::prelude::*;
+use rand::Rng;
+
+/// All calculations for the material are done a tangent space of the intersection.
+pub trait Material<R: Rng> {
+    fn eval(&self, w_in: Dir3, w_out: Dir3, rng: &mut R) -> Color;
+}
+
+pub struct DefaultMaterial {}
+
+impl<R: Rng> Material<R> for DefaultMaterial {
+    fn eval(&self, _w_in: Dir3, _w_out: Dir3, rng: &mut R) -> Color {
+        Color::black()
+    }
+}

ray-tracing-core/src/math/dir3.rs

@@ -1,54 +1,26 @@
 use crate::prelude::*;
 use std::ops::{Add, Div, Mul, Neg, Sub};
 
-#[derive(Debug, Clone, Copy)]
-pub struct Pos3 {
-    x: Float,
-    y: Float,
-    z: Float,
-}
-
 #[derive(Debug, Clone, Copy)]
 pub struct Dir3 {
-    x: Float,
-    y: Float,
-    z: Float,
-}
-
-impl Pos3 {
-    pub fn new(x: Float, y: Float, z: Float) -> Self {
-        Self { x, y, z }
-    }
-
-    pub fn x(self) -> Float {
-        self.x
-    }
-    pub fn y(self) -> Float {
-        self.y
-    }
-    pub fn z(self) -> Float {
-        self.z
-    }
-
-    pub fn zero() -> Self {
-        Self {
-            x: 0.0,
-            y: 0.0,
-            z: 0.0,
-        }
-    }
+    pub(crate) x: Float,
+    pub(crate) y: Float,
+    pub(crate) z: Float,
 }
 
 impl Dir3 {
     pub fn new(x: Float, y: Float, z: Float) -> Self {
         Self { x, y, z }
     }
+
     pub fn x(self) -> Float {
         self.x
     }
+
     pub fn y(self) -> Float {
         self.y
     }
+
     pub fn z(self) -> Float {
         self.z
     }
@@ -61,23 +33,32 @@ impl Dir3 {
         }
     }
 
+    pub fn up() -> Self {
+        Self::new(0.0, 1.0, 0.0)
+    }
+
     pub fn normalize(self) -> Self {
         self / self.length()
     }
-    pub fn length(self) -> Float {
-        Float::sqrt(self.x * self.x + self.y * self.y + self.z * self.z)
+
+    pub fn length_squared(self) -> Float {
+        self.x * self.x + self.y * self.y + self.z * self.z
     }
-}
 
-impl Sub for Pos3 {
-    type Output = Dir3;
+    pub fn length(self) -> Float {
+        Float::sqrt(self.length_squared())
+    }
 
-    fn sub(self, rhs: Self) -> Self::Output {
-        Dir3 {
-            x: self.x - rhs.x,
-            y: self.y - rhs.y,
-            z: self.z - rhs.z,
-        }
+    pub fn dot(self, rhs: Self) -> Float {
+        self.x * rhs.x + self.y * rhs.y + self.z * rhs.z
+    }
+
+    pub fn cross(self, rhs: Self) -> Self {
+        Self::new(
+            self.y * rhs.z - self.z * rhs.y,
+            self.z * rhs.x - self.x * rhs.z,
+            self.x * rhs.y - self.y * rhs.x,
+        )
     }
 }
 
@@ -93,23 +74,11 @@ impl Add for Dir3 {
     }
 }
 
-impl Add<Pos3> for Dir3 {
-    type Output = Pos3;
+impl Add<pos3::Pos3> for Dir3 {
+    type Output = pos3::Pos3;
 
-    fn add(self, rhs: Pos3) -> Self::Output {
-        Pos3 {
-            x: self.x + rhs.x,
-            y: self.y + rhs.y,
-            z: self.z + rhs.z,
-        }
-    }
-}
-
-impl Add<Dir3> for Pos3 {
-    type Output = Pos3;
-
-    fn add(self, rhs: Dir3) -> Self::Output {
-        Pos3 {
+    fn add(self, rhs: pos3::Pos3) -> Self::Output {
+        pos3::Pos3 {
             x: self.x + rhs.x,
             y: self.y + rhs.y,
             z: self.z + rhs.z,
@@ -141,6 +110,18 @@ impl Mul<Float> for Dir3 {
     }
 }
 
+impl Mul<Dir3> for Float {
+    type Output = Dir3;
+
+    fn mul(self, rhs: Dir3) -> Self::Output {
+        Dir3 {
+            x: self * rhs.x,
+            y: self * rhs.y,
+            z: self * rhs.z,
+        }
+    }
+}
+
 impl Div<Float> for Dir3 {
     type Output = Dir3;
 

ray-tracing-core/src/math/mod.rs

@@ -0,0 +1,5 @@
+pub mod dir3;
+pub mod pos3;
+
+pub use dir3::Dir3;
+pub use pos3::Pos3;

ray-tracing-core/src/math/pos3.rs

@@ -0,0 +1,57 @@
+use crate::prelude::*;
+use std::ops::{Add, Sub};
+
+#[derive(Debug, Clone, Copy)]
+pub struct Pos3 {
+    pub(crate) x: Float,
+    pub(crate) y: Float,
+    pub(crate) z: Float,
+}
+
+impl Pos3 {
+    pub fn new(x: Float, y: Float, z: Float) -> Self {
+        Self { x, y, z }
+    }
+
+    pub fn x(self) -> Float {
+        self.x
+    }
+    pub fn y(self) -> Float {
+        self.y
+    }
+    pub fn z(self) -> Float {
+        self.z
+    }
+
+    pub fn zero() -> Self {
+        Self {
+            x: 0.0,
+            y: 0.0,
+            z: 0.0,
+        }
+    }
+}
+
+impl Sub for pos3::Pos3 {
+    type Output = Dir3;
+
+    fn sub(self, rhs: Self) -> Self::Output {
+        Dir3 {
+            x: self.x - rhs.x,
+            y: self.y - rhs.y,
+            z: self.z - rhs.z,
+        }
+    }
+}
+
+impl Add<Dir3> for pos3::Pos3 {
+    type Output = pos3::Pos3;
+
+    fn add(self, rhs: Dir3) -> Self::Output {
+        pos3::Pos3 {
+            x: self.x + rhs.x,
+            y: self.y + rhs.y,
+            z: self.z + rhs.z,
+        }
+    }
+}

ray-tracing-core/src/ray.rs

@@ -2,7 +2,25 @@ use crate::prelude::*;
 
 #[derive(Debug, Clone, Copy)]
 pub struct Ray {
-    pub start: Pos3,
-    pub dir: Dir3,
-    pub time: Float,
+    start: Pos3,
+    dir: Dir3,
+    time: Float,
+}
+
+impl Ray {
+    pub fn new(start: Pos3, dir: Dir3, time: Float) -> Self {
+        Self { start, dir, time }
+    }
+
+    pub fn start(self) -> Pos3 {
+        self.start
+    }
+
+    pub fn dir(self) -> Dir3 {
+        self.dir
+    }
+
+    pub fn time(self) -> Float {
+        self.time
+    }
 }

ray-tracing-core/src/renderer.rs

@@ -0,0 +1,63 @@
+use std::marker::PhantomData;
+
+use crate::{camera::Camera, prelude::*, scene::Scene};
+use rand::Rng;
+
+pub trait ClassicalRenderer<R: Rng> {
+    fn render_pixel(&self, x: u32, y: u32, rng: &mut R) -> Color;
+    fn width(&self) -> u32;
+    fn height(&self) -> u32;
+}
+
+pub struct DepthRenderer<S, C, R>
+where
+    S: Scene<R>,
+    C: Camera<R>,
+    R: Rng,
+{
+    scene: S,
+    camera: C,
+    rng: PhantomData<R>,
+}
+
+impl<S, C, R> DepthRenderer<S, C, R>
+where
+    S: Scene<R>,
+    C: Camera<R>,
+    R: Rng,
+{
+    pub fn new(scene: S, camera: C) -> Self {
+        Self {
+            scene,
+            camera,
+            rng: PhantomData {},
+        }
+    }
+}
+
+impl<S, C, R> ClassicalRenderer<R> for DepthRenderer<S, C, R>
+where
+    S: Scene<R>,
+    C: Camera<R>,
+    R: Rng,
+{
+    fn render_pixel(&self, x: u32, y: u32, rng: &mut R) -> Color {
+        let r = self.camera.forward(x, y, rng);
+
+        if let Some(i) = self.scene.intersect(r, 0.0, Float::INFINITY) {
+            // Color::gray(1.0 / i.t())
+            let c = 0.5 * (i.normal() + Dir3::new(1.0, 1.0, 1.0));
+            Color::new(c.x, c.y, c.z)
+        } else {
+            Color::black()
+        }
+    }
+
+    fn width(&self) -> u32 {
+        self.camera.width()
+    }
+
+    fn height(&self) -> u32 {
+        self.camera.height()
+    }
+}

ray-tracing-core/src/scene.rs

@@ -1,24 +1,34 @@
 use crate::prelude::*;
+use rand::Rng;
 
-pub trait Scene {
-    fn intersect(&self, ray: Ray, min: Float, max: Float) -> Option<Intersection<'_>>;
+pub trait Scene<R: Rng> {
+    fn intersect(&self, ray: Ray, min: Float, max: Float) -> Option<Intersection<'_, R>>;
 }
 
-pub struct Intersection<'sc> {
+pub struct Intersection<'sc, R: Rng> {
     t: Float,
-    material: &'sc dyn Material,
+    normal: Dir3,
+    material: &'sc dyn Material<R>,
 }
 
-impl<'sc> Intersection<'sc> {
-    pub fn new(t: Float, material: &'sc dyn Material) -> Self {
-        Self { t, material }
+impl<'sc, R: Rng> Intersection<'sc, R> {
+    pub fn new(t: Float, normal: Dir3, material: &'sc dyn Material<R>) -> Self {
+        Self {
+            t,
+            normal,
+            material,
+        }
     }
 
     pub fn t(&self) -> Float {
         self.t
     }
 
-    pub fn material(&self) -> &'sc dyn Material {
+    pub fn normal(&self) -> Dir3 {
+        self.normal
+    }
+
+    pub fn material(&self) -> &'sc dyn Material<R> {
         self.material
     }
 }

ray-tracing-image/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "ray-tracing-image"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+image = "0.25.2"
+rand = { version = "0.8.5", features = ["small_rng"] }
+ray-tracing-core = { path = "../ray-tracing-core" }
+ray-tracing-scene = { path = "../ray-tracing-scene" }
+rayon = "1.10.0"

ray-tracing-image/src/main.rs

@@ -0,0 +1,52 @@
+use image::{ImageBuffer, ImageResult, Rgb};
+use rand::{rngs::SmallRng, SeedableRng};
+use ray_tracing_core::{
+    camera::BasicCamera,
+    prelude::*,
+    renderer::{ClassicalRenderer, DepthRenderer},
+};
+use ray_tracing_scene::BasicScene;
+use rayon::prelude::*;
+use std::path::Path;
+
+fn render_image<C: ClassicalRenderer<SmallRng> + Sync>(
+    renderer: C,
+    outputfilename: impl AsRef<Path>,
+    samples_per_pixel: usize,
+) -> ImageResult<()> {
+    let mut data = vec![Color::black(); (renderer.width() * renderer.height()) as usize];
+
+    data.par_iter_mut().enumerate().for_each(|(i, c)| {
+        let x = (i % renderer.width() as usize) as u32;
+        let y = (i / renderer.width() as usize) as u32;
+
+        let mut rng = SmallRng::seed_from_u64((x + y * renderer.width()) as u64);
+        for _ in 0..samples_per_pixel {
+            *c += renderer.render_pixel(x, y, &mut rng) / (samples_per_pixel as Float);
+        }
+    });
+
+    let img = ImageBuffer::from_fn(renderer.width(), renderer.height(), |x, y| {
+        let c = data[(x + y * renderer.width()) as usize];
+        Rgb::<Float>([c.r(), c.g(), c.b()])
+    });
+
+    img.save(outputfilename)
+}
+
+fn main() -> ImageResult<()> {
+    let s = BasicScene::new();
+
+    let c = BasicCamera::new(
+        640,
+        400,
+        Pos3::new(-10.0, 0.0, 0.0),
+        Dir3::new(1.0, 0.0, 0.0),
+        Dir3::up(),
+        Float::to_radians(90.0),
+    );
+
+    let r = DepthRenderer::new(s, c);
+
+    render_image(r, "test.exr", 16)
+}

ray-tracing-scene/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "ray-tracing-scene"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+rand = "0.8.5"
+ray-tracing-core = { path = "../ray-tracing-core" }

ray-tracing-scene/src/lib.rs

@@ -0,0 +1,51 @@
+use rand::Rng;
+use ray_tracing_core::material::DefaultMaterial;
+use ray_tracing_core::prelude::*;
+use ray_tracing_core::scene::{Intersection, Scene};
+
+pub mod sphere;
+
+pub struct BasicScene {
+    spheres: Vec<(Pos3, Float)>,
+}
+
+impl BasicScene {
+    pub fn new() -> Self {
+        Self {
+            spheres: vec![(Pos3::zero(), 1.0), (Pos3::new(0.0, 0.0, 2.5), 2.0)],
+        }
+    }
+}
+
+impl<R: Rng> Scene<R> for BasicScene {
+    fn intersect(&self, ray: Ray, min: Float, max: Float) -> Option<Intersection<'_, R>> {
+        let mut intersection: Option<Intersection<'_, R>> = None;
+
+        for &(c, r) in &self.spheres {
+            let offset = ray.start() - c;
+            let p = Dir3::dot(ray.dir(), offset);
+            let delta = p * p - (offset.length_squared() - r * r);
+
+            if delta >= 0.0 {
+                let d = -p - Float::sqrt(delta);
+
+                let int = Intersection::new(
+                    d,
+                    ((ray.start() + d * ray.dir()) - c).normalize(),
+                    &DefaultMaterial {},
+                );
+                if d >= min && d <= max {
+                    if let Some(i) = intersection.as_ref() {
+                        if i.t() > d {
+                            intersection.replace(int);
+                        }
+                    } else {
+                        intersection = Some(int)
+                    }
+                }
+            }
+        }
+
+        intersection
+    }
+}