const maxTrails = 5;

const starSizeCaps = [3, 10];

const starAlphaCaps = [100, 255];

const trailSizeCaps = [20, 60];

const angleCaps = [100, 130];

const trailWidthCaps = [1, 2];

const offset = 25;

const segs = 50;

const cnv = {w: 800, h: 400};

var colourSet;

​

function setup() {

  createCanvas(cnv.w, cnv.h);

  background(50, 30, 90);

  colourSet = [color(255, 255, 255), color(150, 150, 255), color(255, 255, 120)];

}

​

function draw() {

  if(frameCount <= maxStars) renderStars();

  else if(frameCount <= maxStars + maxTrails) renderTrails();

  else if(frameCount == maxStars + maxTrails + 1) noLoop();

}

​

function renderStars() {

  let randSize = random(starSizeCaps[0], starSizeCaps[1]);

  let randColour = random(colourSet);

  let randPos = [random(0 + offset, cnv.w - offset), random(0 + offset, cnv.h - offset)];

  let randAlpha = random(starAlphaCaps[0], starAlphaCaps[1]);

  randColour.setAlpha(randAlpha);

  if(random() > 0.3 && randSize >= 8) {

    noFill();

    stroke(randColour);

    strokeWeight(2);

  }

  else {

    noStroke();

    fill(randColour);

  }

  ellipse(randPos[0], randPos[1], randSize); 

}

​

function renderTrails() {

  let randLen = random(trailSizeCaps[0], trailSizeCaps[1]);

  let randAngle = random(angleCaps[0], angleCaps[1]);

  let randWid = random(trailWidthCaps[0], trailWidthCaps[1]);

  let randColour = random(colourSet);

  stroke(randColour);

  angleMode(DEGREES);

  let start = createVector(random(-cnv.w / 3, cnv.w / 3)  + cnv.w / 2, random(-cnv.h / 4, cnv.h / 4)  + 5 * cnv.h / 12);

  translate(start);

  let end = createVector(cos(randAngle), sin(randAngle)).mult(randLen);

​

  gradientLine2(createVector(0, 0), end, randWid, randWid + 2, segs);

}

​

function gradientLine2(

  start_v,

  end_v,

  start_weight,

  end_weight,

  segments

) {

  let prev_loc_v = start_v.copy();

  for (let i = 1; i <= segments; i++) {

    let cur_loc_v = p5.Vector.lerp(start_v, end_v, i / segments);

    push();

    strokeCap(SQUARE);

    strokeWeight(lerp(start_weight, end_weight, i / segments));

    line(prev_loc_v.x, prev_loc_v.y, cur_loc_v.x, cur_loc_v.y);

    pop();

    prev_loc_v = cur_loc_v.copy();

  }

}