main.rs

use glam::DVec3;
use indicatif::ProgressIterator;
use itertools::Itertools;
use std::{fs, io};

const IMAGE_HEIGHT: u32 = 256;
const IMAGE_WIDTH: u32 = 256;
const MAX_VALUE: u8 = 255;

fn main() -> io::Result<()> {
    let pixels = (0..IMAGE_HEIGHT)
        .cartesian_product(0..IMAGE_WIDTH)
        .progress_count(
            IMAGE_HEIGHT as u64 * IMAGE_WIDTH as u64,
        )
        .map(|(y, x)| {
            let r = x as f64 / (IMAGE_WIDTH - 1) as f64;
            let g = y as f64 / (IMAGE_HEIGHT - 1) as f64;
            let b = 0.0;
            format!(
                "{} {} {}",
                r * 255.0,
                g * 255.0,
                b * 255.0
            )
        })
        .join("\n");
    fs::write(
        "output.ppm",
        format!(
            "P3
{IMAGE_WIDTH} {IMAGE_HEIGHT}
{MAX_VALUE}
{pixels}
"
        ),
    )?;
    Ok(())
}

struct Ray {
    origin: DVec3,
    direction: DVec3,
}

impl Ray {
    fn at(&self, t: f64) -> DVec3 {
        self.origin + t * self.direction
    }
}