Falling Lines

/*

Falling Lines

​

Particles fall and are slown down by air drag that is being driven from a noise field.

​

jasonlabbe3d.com

twitter.com/russetPotato

*/

​

var spawnCount = 4;

var noiseScale = 0.01;

var noiseSpeed = 1;

var allParticles = [];

var globalHue = 0;

​

function setup() {

  createCanvas(600, 600);

  rectMode(CENTER);

  colorMode(HSB, 255);

  noStroke();

  background(0);

}

​

function draw() {

  background(0, 200);

  for (let i = 0; i < spawnCount; i++) {

    allParticles.push(new Particle(random(width), -100));

  }

  for (let i = allParticles.length - 1; i > -1; i--) {

    let p = allParticles[i];

    p.acc.add(new p5.Vector(0, p.fallRate));

    let n = noise(

      (frameCount * (noiseSpeed * 2) + p.pos.x) * noiseScale, 

      (frameCount * noiseSpeed + p.pos.y) * noiseScale);

    if (n > 0.5) {

      p.vel.mult(p.resistance);

    }

    p.vel.add(p.acc);

    p.pos.add(p.vel);

    p.acc.mult(0);

    p.angle += p.vel.mag();

    fill(p.hue, 200, 255, max(0, 255 - p.vel.mag() * 30));

    push();

    translate(p.pos.x, p.pos.y);

    rotate(radians(p.angle));

    rect(0, 0, p.width, max(0, p.height - p.vel.mag() * 10));

    pop();

    if (p.pos.y > height) {

      allParticles.splice(i, 1);

    }

  }

}