pakt21

See /software/p5js/pakt-februari/pakt21/ for a JavaScript version and /software/supercollider/februari-pakt/pakt21/ for accompanying sound code.

use nannou::prelude::*;

const N: usize = 150;

fn main() {
  nannou::app(model)
    .update(update)
    .simple_window(view)
    .size(640, 480)
    .run();
}
struct Model {
  index: f32,
  pos: Vec<Vec2>,
  last: Vec<Vec2>,
  cols: Vec<Rgb>,
}
fn model(_app: &App) -> Model {
  let index = 0.0;
  let mut pos = vec![];
  let mut last = vec![];
  let mut cols = vec![];
  for i in 0..N {
    let t = i as f32 / N as f32 * PI * 2.0;
    pos.push(vec2(0.0, 0.0));
    last.push(vec2(0.0, 0.0));
    cols.push(rgb(t.sin() * 0.5 + 0.5, (t + PI).sin() * 0.5 + 0.5, 1.0));
  }
  Model {
    index,
    pos,
    last,
    cols,
  }
}
fn update(app: &App, model: &mut Model, _update: Update) {
  let win = app.window_rect();
  let index = app.time * 60.0;
  for i in 0..N {
    let j = i as f32;
    let jj = j.sin() * (j * 2.0).sin();
    model.last[i] = model.pos[i];
    let x = ((j * (index * 0.0126 + jj).sin() * (index * 0.0031).sin() + index) * 0.074).sin();
    let y = ((j * (index * 0.0152 + jj).sin() * (index * 0.0021).sin() + index) * 0.064).cos();
    model.pos[i] = vec2(x, y) * win.wh() * 0.45 + (win.wh() * 0.5);
  }
  model.index = index;
}
fn view(app: &App, model: &Model, frame: Frame) {
  let draw = app.draw();
  let win = app.window_rect();

  if frame.nth() == 0 {
    frame.clear(BLACK);
  } else {
    draw.rect().wh(win.wh()).color(rgba(0.0, 0.0, 0.0, 0.05));
    for i in 0..N {
      let r = (model.pos[i].x - model.last[i].x + model.pos[i].y - model.last[i].y).abs();
      draw.scale_axes(vec3(1.0, -1.0, 1.0))
        .translate(vec3(win.w(), win.h(), 0.0) * -0.5)
        .ellipse()
        .xy(model.pos[i])
        .w_h(r, r)
        .color(model.cols[i]);
    }
  }

  draw.to_frame(app, &frame).unwrap();
}