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use std::{fs::File, io::Write, path::PathBuf};
use nalgebra::Point2;
use crate::algebra::{Scalar, N};
use crate::renderer::Camera;
use crate::particle_system::Particle;
pub struct PPM<const WIDTH: usize, const HEIGHT: usize> {
pub prefix: PathBuf,
buffer: [[bool; WIDTH]; HEIGHT],
// pixels_per_unit: usize,
}
impl<const WIDTH: usize, const HEIGHT: usize> PPM<WIDTH, HEIGHT> {
pub fn new(prefix: PathBuf) -> Self {
Self {
prefix,
buffer: [[false; WIDTH]; HEIGHT],
}
}
pub fn clear_buffer(&mut self) {
self.buffer = [[false; WIDTH]; HEIGHT]
}
pub fn draw_circle(&mut self, center: Point2<Scalar>, radius: Scalar) {
let screen_center = Point2::new((WIDTH / 2) as Scalar, (HEIGHT / 2) as Scalar);
for pixel_row in 0..HEIGHT {
for pixel_col in 0..WIDTH {
let point = Point2::new(pixel_col as Scalar, pixel_row as Scalar);
if (point - center - screen_center.coords).norm() <= radius {
self.buffer[HEIGHT - pixel_row - 1][pixel_col] = true
}
}
}
}
pub fn render_particles(&mut self, particles: &Vec<Particle>, camera: &Camera) {
for p in particles {
let point = camera.world_to_screen_space(p.position);
self.draw_circle(point, p.mass.powf(1.0 / N as Scalar));
}
}
pub fn save_frame(&self, time: Scalar) {
let file_name = format!("frame-{:08.3}", time);
let path = self.prefix.join(file_name);
let mut file = File::create(path).unwrap();
let mut s = format!("P3\n{} {}\n255\n", WIDTH, HEIGHT);
let white = "255 255 255 ";
let black = "0 0 0 ";
for row in self.buffer {
for pixel in row {
let color = if pixel { black } else { white };
s += color
}
s += "\n";
}
file.write(s.as_bytes()).unwrap();
}
}
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