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Renderer 2, now with 100% less threading tools

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I've rewritten the renderer to see if I can make a better model the
second time around. I was having a rough time untangling parts and
refactoring it piece-by-piece.

Next is to hook up the new rendering parts into a single-threaded
build. Once the parts work again, I can look into thread pooling
machinery.
This commit is contained in:
Robert Garrett
2023-09-25 08:20:27 -07:00
parent 60b4407573
commit f03c6280a7
4 changed files with 193 additions and 237 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
src/main.rs
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@@ -1,7 +1,7 @@
mod primitives;
mod renderer;
mod scene;
mod renderer;
use crate::primitives::Vec3;
use crate::scene::{
@@ -46,11 +46,11 @@ fn main() {
// Iterate lines, submitting them as tasks to the thread.
println!("P3\n{} {}\n255", image.0, image.1);
let context = renderer::RenderContext {
camera: cam,
camera: &scene.camera,
image,
max_depth,
samples_per_pixel,
world,
world: scene.world,
};
thread::scope(|s| {

106
src/primitives.rs
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@@ -17,6 +17,96 @@ use rand::Rng;
use rand::rngs::SmallRng;
use rand::distributions::Uniform;
pub type Vec2i = Vec2<i32>;
pub type Vec2f = Vec2<f32>;
#[derive (Clone, Copy, PartialEq, PartialOrd, Debug)]
pub struct Vec2<T>{
pub x: T,
pub y: T,
}
impl Vec2<f32> {
pub fn zero() -> Vec2<f32> {
Vec2{ x: 0.0, y: 0.0 }
}
pub fn ones() -> Vec2<f32> {
Vec2{ x: 1.0, y: 1.0 }
}
pub fn rand(srng: &mut SmallRng, distrib: Uniform<f32>) -> Vec2<f32> {
Vec2 { x: srng.sample(distrib), y: srng.sample(distrib) }
}
}
impl <T> Vec2<T>
where T: std::ops::Mul{
pub fn new(x: T, y: T) -> Vec2<T> {
Vec2{x, y}
}
}
impl <T> Add for Vec2 <T>
where T: std::ops::Add<Output = T>{
type Output = Vec2<T>;
fn add(self, other: Vec2<T>) -> Vec2<T> {
Vec2 { x: self.x + other.x, y: self.y + other.y }
}
}
impl <T> Mul for Vec2<T>
where T: std::ops::Mul<Output = T>{
type Output = Vec2<T>;
fn mul(self, other: Vec2<T>) -> Vec2<T> {
Vec2 {
x: self.x * other.x,
y: self.y * other.y
}
}
}
impl Div<f32> for Vec2<f32>{
type Output = Vec2<f32>;
fn div(self, other: f32) -> Vec2<f32> {
Vec2 {
x: 1.0/other * self.x,
y: 1.0/other * self.y
}
}
}
impl Div<i32> for Vec2<i32>{
type Output = Vec2<i32>;
fn div(self, other: i32) -> Vec2<i32> {
Vec2 {
x: self.x / other,
y: self.y / other
}
}
}
impl <T> Div<Vec2<T>> for Vec2<T>
where T: std::ops::Div<Output = T>{
type Output = Vec2<T>;
fn div(self, other: Vec2<T>) -> Vec2<T> {
Vec2 {
x: self.x / other.x,
y: self.y / other.y
}
}
}
impl <T> Display for Vec2<T>
where T: Display { // nested type still needs to have Display
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
let str = format!("{} {}", self.x, self.y);
fmt.write_str(&str)
}
}
#[derive(Copy, Clone, PartialEq, PartialOrd, Debug)]
pub struct Vec3{
pub x: f32,
@@ -308,6 +398,22 @@ pub struct Rect {
pub h: i32,
}
impl Rect{
pub fn pos(&self) -> Vec2i {
Vec2i {
x: self.x,
y: self.y,
}
}
pub fn size(&self) -> Vec2i {
Vec2i {
x: self.w - self.x,
y: self.h - self.y,
}
}
}
#[cfg(test)]
mod test{
use super::*;

317
src/renderer.rs
View File

@@ -1,270 +1,121 @@
use crate::primitives::{Vec3, Ray, Rect};
use crate::primitives::{
Vec2i,
Vec2f,
Vec3,
Ray,
Rect,
};
use crate::scene::{
Camera,
Hittable,
Scene,
};
use core::cmp::Ordering;
use std::thread;
use std::sync::mpsc;
use std::ops;
use rand::Rng;
use rand::rngs::SmallRng;
use rand::distributions::Uniform;
use itertools::Itertools;
// =================
// Description parts
// =================
const SKY_COLOR: Vec3 = Vec3 { x: 0.5, y: 0.7, z: 1.0};
#[derive (Clone)]
pub struct RenderContext{
pub image: (i32, i32),
pub samples_per_pixel: u32,
pub max_depth: u32,
pub world: Hittable,
pub camera: Camera,
struct Distrs{
zero_one: Uniform<f32>,
one_one: Uniform<f32>,
}
pub struct DistributionContianer {
pub distrib_zero_one: Uniform<f32>,
pub distrib_plusminus_one: Uniform<f32>,
struct RenderProperties {
samples: u32, // samples are averaged results over a pixel
bounces: u32, // bounces are how far the ray will travel (in hits not total distance)
}
impl DistributionContianer {
fn new() -> Self {
DistributionContianer {
distrib_zero_one: Uniform::new(0.0, 1.0),
distrib_plusminus_one: Uniform::new(-1.0, 1.0),
}
}
fn to_uv(coord: Vec2i, img_size: Vec2i) -> Vec2f {
let u = (coord.x as f32) / ((img_size.x - 1) as f32);
let v = (coord.y as f32) / ((img_size.y - 1) as f32);
Vec2f::new(u, v)
}
// =============
// Drawing Parts
// =============
fn render_line(y: i32, small_rng: &mut SmallRng, context: RenderContext, distr: &DistributionContianer) -> Vec<Vec3> {
//TODO: Ensure that the compiler hoists the distribution's out as constants
// else, do so manually
(0..context.image.0).map(|x| {
sample_pixel(x, y, small_rng, &context, distr)
}).collect()
}
fn ray_color(r: Ray, world: &Hittable, depth: u32, srng: &mut SmallRng, distrib: Uniform<f32> ) -> Vec3 {
// recursion depth guard
fn ray_color(
r: Ray, surface: &Hittable, depth: u32,
rng: &mut SmallRng,
distr: &Distrs,
) -> Vec3 {
// recursion guard
if depth == 0 {
return Vec3::zero();
}
if let Some(rec) = world.hit(r, 0.001, f32::INFINITY){
// cast a ray, interrogate hit record
if let Some(record) = surface.hit(r, 0.001, f32::INFINITY){
let mut scattered = Ray {
orig: Vec3::zero(),
dir: Vec3::zero()
dir: Vec3::zero(),
};
let mut attenuation = Vec3::zero();
if rec.material.scatter(r, &rec, &mut attenuation, &mut scattered, srng) {
return attenuation * ray_color(scattered, world, depth-1, srng, distrib);
};
}
if record.material.scatter(
r,
&record,
&mut attenuation,
&mut scattered,
rng
) {
return attenuation * ray_color(
scattered, surface, depth-1, rng, distr
);
}
} // TODO: explicit else block
// Rust gets angry about the inner if{} block because it evaluates to ()
// when the else path is taken. This is a problem for a function
// that returns Vec3 and not ().
let unitdir = Vec3::as_unit(r.dir);
let t = 0.5 * (unitdir.y + 1.0);
return Vec3::ones() * (1.0 - t) + Vec3::new(0.5, 0.7, 1.0) * t
{ // when nothing is struck, return sky color
let unitdir = Vec3::as_unit(r.dir);
let t = 0.5 * (unitdir.y + 1.0);
return Vec3::ones() * (1.0 - t) + SKY_COLOR * t
}
}
fn sample_pixel(x: i32, y: i32, small_rng: &mut SmallRng, context: &RenderContext, distr: &DistributionContianer) -> Vec3{
(0..context.samples_per_pixel).into_iter().fold(
fn sample_pixel(
coord: Vec2i, // location in image/screen space
scene: &Scene, // scene we're drawing
render_props: &RenderProperties,
img_size: Vec2i,
// Supplied by the execution environment (the thread)
rng: &mut SmallRng,
dist: &Distrs,
) -> Vec3{
(0..render_props.samples)
.fold(
Vec3::zero(),
|color, _sample| {
let u = ((x as f32) + small_rng.sample(distr.distrib_zero_one)) / ((context.image.0 - 1) as f32);
let v = ((y as f32) + small_rng.sample(distr.distrib_zero_one)) / ((context.image.1 - 1) as f32);
let ray = context.camera.get_ray(u, v, small_rng);
color + ray_color(ray, &context.world, context.max_depth, small_rng, distr.distrib_plusminus_one)
|color, _sample| -> Vec3 {
let uv = to_uv(coord, img_size);
let ray = scene.camera.get_ray(uv.x, uv.y, rng);
color + ray_color(ray, &scene.world, render_props.bounces, rng, dist)
}
)
}
// ===============
// Execution parts
// ===============
/* Iterable that produces pixels left-to-right, top-to-bottom.
* `Tile`s represent the render space, not the finished image.
* There is no internal pixel buffer
*/
type TileCursorIter = itertools::Product<ops::Range<i32>, ops::Range<i32>>;
struct Tile {
bounds: Rect,
context: RenderContext,
small_rng: SmallRng,
rand_distr: DistributionContianer,
cursor: TileCursorIter,
pixels: Vec<Vec3>,
}
impl Tile{
fn new(
bounds: Rect,
context: RenderContext,
small_rng: SmallRng,
rand_distr: DistributionContianer
) -> Self
{
Tile { bounds, context, small_rng, rand_distr,
cursor: (bounds.x..(bounds.x + bounds.w))
.cartesian_product(bounds.y..(bounds.y + bounds.h)
impl Tile {
pub fn render_line(
bounds: Rect, y: i32, // bounding rect and line
scene: &Scene,
properties: &RenderProperties,
rng: &mut SmallRng, distr: &Distrs // rng utils
) -> Self {
let pixels = (0..bounds.w)
.map ( |x| -> Vec3{
sample_pixel(
Vec2i{x, y},
scene,
properties,
bounds.size(),
rng,
distr
)
}
})
.collect();
Self { bounds, pixels }
}
}
impl Iterator for Tile {
type Item = Vec3;
fn next(&mut self) -> Option<Self::Item> {
if let Some((x, y)) = self.cursor.next(){
Some(sample_pixel(
x, y,
&mut self.small_rng,
&self.context,
&self.rand_distr,
))
} else {
None
}
}
}
#[derive (Clone)]
pub enum RenderCommand{
Stop,
Line { line_num: i32, context: RenderContext },
}
pub struct RenderResult {
pub line_num: i32,
pub line: Vec<Vec3>,
}
impl Ord for RenderResult {
fn cmp(&self, other: &Self) -> Ordering {
if self.line_num > other.line_num {
Ordering::Less
} else if self.line_num < other.line_num {
Ordering::Greater
} else {
Ordering::Equal
}
}
}
impl PartialOrd for RenderResult {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
Some(self.cmp(other))
}
}
impl PartialEq for RenderResult {
fn eq(&self, other: &Self) -> bool {
self.line_num == other.line_num
}
}
impl Eq for RenderResult {}
/*
* The dispatcher will hold a list of threads, and a list of command input channels to match.
* Helper functions exist to input jobs serially, and then dispatch them to an open thread.
*
* Since receivers can be matched to several senders, the input end of the result channel will
* be cloned and given to each of the threads.
* TODO: Consider holding a copy of the render_tx end in case threads exit early and need to
* be restored.
*/
pub struct Dispatcher{
handles: Vec<thread::JoinHandle<()>>,
command_transmitters: Vec<mpsc::SyncSender<RenderCommand>>,
next_to_feed: usize, // gonna do a round-robin style dispatch, ig.
}
impl Dispatcher {
pub fn new(srng: &SmallRng, num_threads: usize) -> (Dispatcher, mpsc::Receiver<RenderResult> ) {
let mut handles = Vec::new();
let mut command_transmitters = Vec::<mpsc::SyncSender<RenderCommand>>::new();
let (render_tx, render_rx) = mpsc::sync_channel::<RenderResult>(1);
for _ in 0..num_threads {
// create new command tx/rx pairs. Store tx in the list, give rx to the thread.
let (command_tx, command_rx) = mpsc::sync_channel::<RenderCommand>(1);
// TODO: Pick appropriate command queue depth (or make it controllable, even)
let mut srng = srng.clone();
let threads_result_tx = render_tx.clone();
let distribs = DistributionContianer::new();
let thread_handle = thread::spawn(move || {
while let Ok(job) = command_rx.recv() {
match job {
RenderCommand::Stop => {
break;
}
RenderCommand::Line { line_num, context } => {
let line = render_line(line_num, &mut srng, context, &distribs);
let result = RenderResult { line_num, line };
threads_result_tx.send(result).unwrap();
}
}
}
});
handles.push(thread_handle);
command_transmitters.push(command_tx);
}
// finally, stash everything in the Dispatcher struct and return.
(
Dispatcher{
handles,
command_transmitters,
next_to_feed: 0,
},
render_rx
)
}
//TODO: Reconsider round-robin dispatch
// When passing the message to threads which are still busy, this function
// will block (it's a sync_channel). While blocked, other threads could
// become available and left idle.
pub fn submit_job(&mut self, command: RenderCommand) -> Result<(), mpsc::SendError<RenderCommand>> {
// Stop command is special. We'll broadcast it to all threads.
if let RenderCommand::Stop = command {
for channel in &self.command_transmitters {
return channel.send(command.clone());
}
}
// Check that `next_to_feed` is in-bounds, and then insert.
// index is post-incremented with this function call.
// wrap when at length (0-indexed so last valid index is len-1)
if self.next_to_feed == self.handles.len() {
self.next_to_feed = 0;
} else if self.next_to_feed > self.handles.len() {
panic!("How the hell did a +=1 skip past the maximum allowed size?");
}
match self.command_transmitters.get(self.next_to_feed){
Some(target) => target.send(command).unwrap(),
None => panic!("oh god oh fuck"),
}
self.next_to_feed += 1;
Ok(())
}
}

1
src/scene.rs
View File

@@ -169,7 +169,6 @@ pub fn degrees_to_radians(degrees: f32) -> f32 {
degrees * std::f32::consts::PI / 180.0
}
#[derive (Clone, Copy)]
pub struct Camera {
origin: Vec3,
lower_left_corner: Vec3,