ishan/raytracing-in-a-weekend
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Refactoring, Completed Simple Sphere and Surface Normal Sphere

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This commit is contained in:
Ishan Jain 2019-06-24 22:10:45 +05:30
parent b368aad313
commit c53beb8cc1
10 changed files with 181 additions and 118 deletions
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2
ria-weekend/Cargo.lock generated
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@ -1,3 +1,5 @@
# This file is automatically @generated by Cargo.
# It is not intended for manual editing.
[[package]]
name = "autocfg"
version = "0.1.2"

54
ria-weekend/examples/surface_normal_sphere.rs
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@ -1,54 +0,0 @@
extern crate ria_weekend;
use ria_weekend::{demo::Demo, ray, ray::Ray, vec3::Vec3};
fn main() {
let demo = Demo::new("surface_normal_sphere");
let dimensions = demo.dimensions();
let mut buf = String::new();
// linear interpolation based on y coordinate
// top to down
let color = |ray: Ray| -> Vec3 {
// center at z=-1. xy axis cuts sphere in half
// blending parameter
let t = ray_hit_sphere(Vec3::new(0.0, 0.0, 1.0), 0.5, &ray);
if t > 0.0 {
// For all rays that hit sphere, return red color
// This will result in a sphere that is red in color
let N = ray.point_at_parameter(t) - Vec3::new(0.0, 0.0, -1.0);
return Vec3::new(N.x() + 1.0, N.y() + 1.0, N.z() + 1.0) * 0.5;
}
let unit_direction = ray.direction().unit_vector();
// For rays that don't hit sphere, It'll paint the gradient as the background
// Linear gradient depends on y
let t = 0.5 * (unit_direction.y() + 1.0);
// start color + end color
Vec3::new(1.0, 1.0, 1.0) * (1.0 - t) + Vec3::new(0.0, 0.0, 0.0) * t
};
ray::create_ray_demo(&mut buf, dimensions, color);
demo.save_as_ppm(buf);
}
fn ray_hit_sphere(center: Vec3, radius: f32, ray: &Ray) -> f32 {
// dot(A + t*B - C, A + t*B - C) = R*R
// when expanded we get
// t * t * dot(B, B) + 2 * t * dot(B, A-C) + dot(A-C, A-C) - R*R = 0
// A-C
let ac = ray.origin() - center;
let a = ray.direction().dot(&ray.direction());
let b = 2.0 * ac.dot(&ray.direction());
let c = ac.dot(&ac) - radius * radius;
let discriminant = b * b - 4.0 * a * c;
if discriminant >= 0.0 {
// return quadratic root
(-b + discriminant.sqrt()) / (2.0 * a)
} else {
-1.0
}
}

16
ria-weekend/src/demos/linear_interpolation_y.rs
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@ -9,9 +9,13 @@ impl crate::Demo for LinearInterpolationY {
}
fn render(&self, buf: &mut Vec<u8>, w: usize, h: usize) {
let lower_left_corner = Vec3::new(-2.0, -1.0, -1.0);
let horizontal = Vec3::new(4.0, 0.0, 0.0);
let vertical = Vec3::new(0.0, 2.0, 0.0);
// in my case, The resolution is 1200x800
// These numbers are calculated by first calculating the aspect ratio
// and then just figuring out lower left corner, Width(2 x aspect ratio width)
// Height(2 x aspect ratio height)
let lower_left_corner = Vec3::new(-3.0, -2.0, -1.0);
let horizontal = Vec3::new(6.0, 0.0, 0.0);
let vertical = Vec3::new(0.0, 4.0, 0.0);
// Observer position
let origin = Vec3::new(0.0, 0.0, 0.0);
@ -25,9 +29,9 @@ impl crate::Demo for LinearInterpolationY {
let ray = Ray::new(origin, lower_left_corner + horizontal * u + vertical * v);
let color = calc_color(ray);
let ir = (255.99 * color[0]) as u8;
let ig = (255.99 * color[1]) as u8;
let ib = (255.99 * color[2]) as u8;
let ir = (255.99 * color.r()) as u8;
let ig = (255.99 * color.g()) as u8;
let ib = (255.99 * color.b()) as u8;
buf[offset] = ir;
buf[offset + 1] = ig;

6
ria-weekend/src/demos/mod.rs
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@ -1,7 +1,9 @@
mod linear_interpolation_y;
mod simple_sphere;
mod ppm_example;
mod simple_sphere;
mod surface_normal_sphere;
pub use linear_interpolation_y::LinearInterpolationY;
pub use simple_sphere::SimpleSphere;
pub use ppm_example::PpmExample;
pub use simple_sphere::SimpleSphere;
pub use surface_normal_sphere::SurfaceNormalSphere;

6
ria-weekend/src/demos/ppm_example.rs
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@ -12,9 +12,9 @@ impl crate::Demo for PpmExample {
for i in 0..w {
let color = Vec3::new((i as f32) / (w as f32), (j as f32) / (h as f32), 0.2);
let ir = (255.99 * color[0]) as u8;
let ig = (255.99 * color[1]) as u8;
let ib = (255.99 * color[2]) as u8;
let ir = (255.99 * color.r()) as u8;
let ig = (255.99 * color.g()) as u8;
let ib = (255.99 * color.b()) as u8;
buf[offset] = ir;
buf[offset + 1] = ig;

41
ria-weekend/src/demos/simple_sphere.rs
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@ -1,5 +1,7 @@
use crate::{ray::Ray, vec3::Vec3};
const RADIUS: f32 = 0.8;
pub struct SimpleSphere;
impl crate::Demo for SimpleSphere {
@ -8,9 +10,13 @@ impl crate::Demo for SimpleSphere {
}
fn render(&self, buf: &mut Vec<u8>, w: usize, h: usize) {
let lower_left_corner = Vec3::new(-2.0, -1.0, -1.0);
let horizontal = Vec3::new(4.0, 0.0, 0.0);
let vertical = Vec3::new(0.0, 2.0, 0.0);
// in my case, The resolution is 1200x800
// These numbers are calculated by first calculating the aspect ratio
// and then just figuring out lower left corner, Width(2 x aspect ratio width)
// Height(2 x aspect ratio height)
let lower_left_corner = Vec3::new(-3.0, -2.0, -1.0);
let horizontal = Vec3::new(6.0, 0.0, 0.0);
let vertical = Vec3::new(0.0, 4.0, 0.0);
// Observer position
let origin = Vec3::new(0.0, 0.0, 0.0);
@ -24,9 +30,9 @@ impl crate::Demo for SimpleSphere {
let ray = Ray::new(origin, lower_left_corner + horizontal * u + vertical * v);
let color = calc_color(ray);
let ir = (255.99 * color[0]) as u8;
let ig = (255.99 * color[1]) as u8;
let ib = (255.99 * color[2]) as u8;
let ir = (255.99 * color.r()) as u8;
let ig = (255.99 * color.g()) as u8;
let ib = (255.99 * color.b()) as u8;
buf[offset] = ir;
buf[offset + 1] = ig;
@ -38,15 +44,20 @@ impl crate::Demo for SimpleSphere {
}
fn ray_hit_sphere(center: Vec3, radius: f32, ray: &Ray) -> bool {
// dot(A + t*B - C, A + t*B - C) = R*R
// when expanded we get
// t * t * dot(B, B) + 2 * t * dot(B, A-C) + dot(A-C, A-C) - R*R = 0
// For a point to lie on a circle,
// (x-cx)^2 + (y-cy)^2 + (z-cz)^2 = R * R
// should hold true
// Aforementioned equation can be rewritten as,
// dot(p-c, p-c) since the dot product of dis-similar axises will be zero
// the expansion of this dot product will result in the same equation
// i.e. t * t * dot(B,B) + 2 * t * dot(B, A-C) + dot(A-C, A-C)
// Vector from circle center to point
let pc = ray.origin() - center;
// A-C
let ac = ray.origin() - center;
let a = ray.direction().dot(&ray.direction());
let b = 2.0 * ac.dot(&ray.direction());
let c = ac.dot(&ac) - radius * radius;
let b = 2.0 * pc.dot(&ray.direction());
let c = pc.dot(&pc) - radius * radius;
let discriminant = b * b - 4.0 * a * c;
discriminant > 0.0
@ -55,8 +66,8 @@ fn ray_hit_sphere(center: Vec3, radius: f32, ray: &Ray) -> bool {
fn calc_color(ray: Ray) -> Vec3 {
// linear interpolation based on y coordinate
// top to down
// center at z=-1. xy axis cuts sphere in half
if ray_hit_sphere(Vec3::new(0.0, 0.0, 1.0), 0.5, &ray) {
// center at z=-1. xy axis cuts sphere in 4 parts
if ray_hit_sphere(Vec3::new(0.0, 0.0, -1.0), RADIUS, &ray) {
// For all rays that hit sphere, return red color
// This will result in a sphere that is red in color
return Vec3::new(1.0, 0.0, 0.0);

79
ria-weekend/src/demos/surface_normal_sphere.rs Normal file
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@ -0,0 +1,79 @@
use crate::{demo::Demo, ray, ray::Ray, vec3::Vec3};
const RADIUS: f32 = 0.8;
pub struct SurfaceNormalSphere;
impl crate::Demo for SurfaceNormalSphere {
fn name(&self) -> String {
"surface_normal_sphere".to_owned()
}
fn render(&self, buf: &mut Vec<u8>, w: usize, h: usize) {
// in my case, The resolution is 1200x800
// These numbers are calculated by first calculating the aspect ratio
// and then just figuring out lower left corner, Width(2 x aspect ratio width)
// Height(2 x aspect ratio height)
let lower_left_corner = Vec3::new(-3.0, -2.0, -1.0);
let horizontal = Vec3::new(6.0, 0.0, 0.0);
let vertical = Vec3::new(0.0, 4.0, 0.0);
// Observer position
let origin = Vec3::new(0.0, 0.0, 0.0);
let mut offset = 0;
for j in 0..h {
for i in 0..w {
let u = i as f32 / w as f32;
let v = j as f32 / h as f32;
let ray = Ray::new(origin, lower_left_corner + horizontal * u + vertical * v);
let color = calculate_color(ray);
let ir = (255.99 * color.r()) as u8;
let ig = (255.99 * color.g()) as u8;
let ib = (255.99 * color.b()) as u8;
buf[offset] = ir;
buf[offset + 1] = ig;
buf[offset + 2] = ib;
offset += 4;
}
}
}
}
fn calculate_color(ray: Ray) -> Vec3 {
// center at z=-1. xy axis cuts sphere in half
// blending parameter
let t = ray_hit_sphere(Vec3::new(0.0, 0.0, -1.0), RADIUS, &ray);
if t > 0.0 {
// For all rays that hit sphere, return red color
// This will result in a sphere that is red in color
let n = (ray.point_at_parameter(t) - Vec3::new(0.0, 0.0, -1.0)).unit_vector();
return Vec3::new(n.x() + 1.0, n.y() + 1.0, n.z() + 1.0) * 0.5;
}
let unit_direction = ray.direction().unit_vector();
// For rays that don't hit sphere, It'll paint the gradient as the background
// Linear gradient depends on y
let t = 0.5 * (unit_direction.y() + 1.0);
// start color + end color
Vec3::new(1.0, 1.0, 1.0) * (1.0 - t) + Vec3::new(0.5, 0.7, 1.0) * t
}
fn ray_hit_sphere(center: Vec3, radius: f32, ray: &Ray) -> f32 {
// dot(A + t*B - C, A + t*B - C) = R*R
// when expanded we get
// t * t * dot(B, B) + 2 * t * dot(B, A-C) + dot(A-C, A-C) - R*R = 0
let oc = ray.origin() - center;
let a = ray.direction().dot(&ray.direction());
let b = 2.0 * oc.dot(&ray.direction());
let c = oc.dot(&oc) - radius * radius;
let discriminant = b * b - 4.0 * a * c;
if discriminant >= 0.0 {
// return quadratic root
(-b - discriminant.sqrt()) / (2.0 * a)
} else {
-1.0
}
}

45
ria-weekend/src/main.rs
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@ -4,7 +4,7 @@ mod ray;
mod vec3;
use demo::Demo;
use demos::{LinearInterpolationY, PpmExample, SimpleSphere};
use demos::{LinearInterpolationY, PpmExample, SimpleSphere, SurfaceNormalSphere};
use sdl2::{
event::{Event, WindowEvent},
keyboard::Keycode,
@ -19,7 +19,7 @@ fn main() -> Result<(), String> {
let sdl_ctx = sdl2::init()?;
let video_subsys = sdl_ctx.video()?;
let (mut width, mut height): (usize, usize) = (500, 500);
let (mut width, mut height): (usize, usize) = (1200, 800);
let mut window = video_subsys
.window("Ray tracing in a weekend", width as u32, height as u32)
@ -35,7 +35,7 @@ fn main() -> Result<(), String> {
.build()
.map_err(|e| e.to_string())?;
// Buffer to store a RGBA framebuffer
// RGBA framebuffer
let mut buffer = vec![0; height * width * 4];
let texture_creator = canvas.texture_creator();
@ -43,10 +43,10 @@ fn main() -> Result<(), String> {
.create_texture_static(PixelFormatEnum::BGR888, width as u32, height as u32)
.map_err(|e| e.to_string())?;
let mut active_demo: Box<Demo> = Box::new(LinearInterpolationY);
let mut active_demo: Box<dyn Demo> = Box::new(PpmExample);
//println!("{:?} {:?} {:?}", texture.query(), texture.color_mod(), texture.alpha_mod());
let mut should_update = true;
loop {
for event in event_pump.poll_iter() {
match event {
@ -58,15 +58,31 @@ fn main() -> Result<(), String> {
Event::KeyUp {
keycode: Some(Keycode::Num1),
..
} => active_demo = Box::new(PpmExample),
} => {
should_update = true;
active_demo = Box::new(PpmExample);
}
Event::KeyUp {
keycode: Some(Keycode::Num2),
..
} => active_demo = Box::new(LinearInterpolationY),
} => {
should_update = true;
active_demo = Box::new(LinearInterpolationY);
}
Event::KeyUp {
keycode: Some(Keycode::Num3),
..
} => active_demo = Box::new(SimpleSphere),
} => {
should_update = true;
active_demo = Box::new(SimpleSphere);
}
Event::KeyUp {
keycode: Some(Keycode::Num4),
..
} => {
should_update = true;
active_demo = Box::new(SurfaceNormalSphere);
}
Event::KeyUp {
keycode: Some(Keycode::S),
..
@ -81,14 +97,17 @@ fn main() -> Result<(), String> {
texture = texture_creator
.create_texture_static(PixelFormatEnum::BGR888, width as u32, height as u32)
.expect("error in resizing texture");
should_update = true;
}
_ => {}
};
}
active_demo.render(&mut buffer, width, height);
texture.update(None, &buffer, width * 4);
canvas.copy(&texture, None, None);
canvas.present();
if should_update {
active_demo.render(&mut buffer, width, height);
texture.update(None, &buffer, width * 4);
canvas.copy(&texture, None, None);
canvas.present();
should_update = false;
}
}
}

14
ria-weekend/src/ray.rs
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@ -1,5 +1,6 @@
use crate::vec3::Vec3;
#[derive(Debug)]
pub struct Ray {
a: Vec3,
b: Vec3,
@ -9,13 +10,16 @@ impl Ray {
pub fn new(a: Vec3, b: Vec3) -> Ray {
Ray { a, b }
}
pub fn origin(&self) -> Vec3 {
return self.a;
#[inline]
pub const fn origin(&self) -> Vec3 {
self.a
}
pub fn direction(&self) -> Vec3 {
return self.b;
#[inline]
pub const fn direction(&self) -> Vec3 {
self.b
}
#[inline]
pub fn point_at_parameter(&self, t: f32) -> Vec3 {
return self.a + self.b * t;
self.a + self.b * t
}
}

36
ria-weekend/src/vec3.rs
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@ -6,43 +6,51 @@ pub struct Vec3 {
}
impl Vec3 {
#[inline]
pub fn new(a: f32, b: f32, c: f32) -> Vec3 {
Vec3 { inner: [a, b, c] }
}
#[inline]
pub fn x(&self) -> f32 {
self[0]
}
#[inline]
pub fn y(&self) -> f32 {
self[1]
}
#[inline]
pub fn z(&self) -> f32 {
self[2]
}
#[inline]
pub fn r(&self) -> f32 {
self[0]
}
#[inline]
pub fn g(&self) -> f32 {
self[1]
}
#[inline]
pub fn b(&self) -> f32 {
self[2]
}
#[inline]
pub fn length(&self) -> f32 {
self.sq_len().sqrt()
}
#[inline]
pub fn sq_len(&self) -> f32 {
self[0] * self[0]
+ self[1] * self[1]
+ self[2] * self[2]
self[0] * self[0] + self[1] * self[1] + self[2] * self[2]
}
#[inline]
pub fn dot(&self, v: &Vec3) -> f32 {
self[0] * v[0] + self[1] * v[1] + self[2] * v[2]
}
#[inline]
pub fn cross(&self, v: &Vec3) -> Vec3 {
Vec3 {
inner: [
@ -52,7 +60,7 @@ impl Vec3 {
],
}
}
#[inline]
pub fn unit_vector(&self) -> Vec3 {
let length = self.length();
Vec3 {
@ -66,11 +74,7 @@ impl Add for Vec3 {
fn add(self, o: Vec3) -> Vec3 {
Vec3 {
inner: [
self[0] + o[0],
self[1] + o[1],
self[2] + o[2],
],
inner: [self[0] + o[0], self[1] + o[1], self[2] + o[2]],
}
}
}
@ -80,11 +84,7 @@ impl Sub for Vec3 {
fn sub(self, o: Vec3) -> Vec3 {
Vec3 {
inner: [
self[0] - o[0],
self[1] - o[1],
self[2] - o[2],
],
inner: [self[0] - o[0], self[1] - o[1], self[2] - o[2]],
}
}
}
@ -119,11 +119,7 @@ impl Div<Vec3> for Vec3 {
fn div(self, o: Vec3) -> Vec3 {
Vec3 {
inner: [
self[0] / o[0],
self[1] / o[1],
self[2] / o[2],
],
inner: [self[0] / o[0], self[1] / o[1], self[2] / o[2]],
}
}
}