use image::{ImageBuffer, Rgba, RgbaImage};
use std::f64::consts::PI;
use std::fs;

fn chladni(x: f64, y: f64, n: f64, m: f64, eps: f64) -> f64 {
    (n * PI * x).cos() * (m * PI * y).cos() + eps * (m * PI * x).cos() * (n * PI * y).cos()
}

fn generate_png(n: u32, m: u32, width: u32, height: u32, eps: f64) {
    let mut img: RgbaImage = ImageBuffer::new(width, height);

    for (x, y, pixel) in img.enumerate_pixels_mut() {
        // Centrage
        let xf = (x as f64 / width as f64) * 2.0 - 1.0;
        let yf = (y as f64 / height as f64) * 2.0 - 1.0;

        let val = chladni(xf, yf, n as f64, m as f64, eps);

        let bright = if val.abs() < 0.08 { 255 } else { 0 }; // Sans variation d'alpha

        // let intensity = val.abs();
        // let bright = (((0.08 - intensity).max(0.0) / 0.08) * 255.0) as u8;
        *pixel = Rgba([0, 0, 0, bright]);
        // *pixel = Rgb([brigh, brigh, brigh]);
    }

    let filename = format!("out/chladni_{}_{}_{}.png", n, m, eps);
    img.save(&filename).unwrap();
    println!("{}", filename);
}

fn main() {
    let width = 1000;
    let height = 1000;
    let max_n = 300;
    let max_m = 300;

    fs::create_dir_all("out").expect("Erreur");

    for n in 1..max_n {
        for m in 1..max_m {
            generate_png(n, m, width, height, -1.0);
            generate_png(n, m, width, height, 1.0);
        }
    }
}