starry

float seed;
float strokeWidth;
void setup() {

  size(800,500);
  background(0);
  seed = random(10000);
  strokeWidth = 15f/800*width;
}

void draw() {
  if (strokeWidth > 1) {
    for (int i = 0; i < 100; i++)placeStroke(random(width), random(height), 15f/800*width, 15f/800*width);
    strokeWidth *= .85;
  }
}
void keyPressed() {
  if (key == 's') {
    saveFrame("this-####.jpg");
  } else {
    seed = random(10000);
    strokeWidth = 15f/800*width;
  }
}

void dobackground() {
  for (float x = 0; x < width; x++) {
  }
}

color backgroundColor(float x, float y) {
  color sky = color(#1339CE);
  color whitesky = color(#7993F0);
  float whiteskyfactor = noise(x*.005, y*.01, seed);
  whiteskyfactor -= .6;
  whiteskyfactor = smoothstep(-.1, .1, whiteskyfactor);
  sky = lerpColor(sky, whitesky, whiteskyfactor);
  color star = color(#EDED8B);
  float starfactor = noise(x*.005, y*.005, seed);
  starfactor = pow(starfactor, 1.7);
  starfactor = starfactor-.5;
  starfactor = smoothstep(-.03, .05, starfactor);
  sky = lerpColor(sky, star, starfactor);
  return sky;
}



void placeStroke(float x, float y, float w, float h) {
  float rw = random(1)*w;
  float t = random(PI*2);
  for (float i = 0; i < rw; i++) {

    t += PI*2/rw;
    pushMatrix();
    float rx, ry;
    rx = random(-w, w);
    ry = random(-h, h);
    translate(x, y);
    translate(rx, ry);
    rotate(t);
    strokeWeight(strokeWidth);
    translate(0, -h/2);
    color c =pickColor(rx+x, ry+y);
    color b = color(random(255));
    c = lerpColor(c,b,random(.2));
    stroke(c);
    line(0, 0, 0, h);
    popMatrix();
  }
}
float smoothstep(float edge0, float edge1, float t) {
  t =constrain((t-edge0)/(edge1-edge0), 0, 1);
  return t;
}

color pickColor(float x, float y) {
  color c;
  float ny = noise(x*.015, seed);
  ny *= height;
  float d = y-ny-height/4;
  float mountainvssky = smoothstep(-20, 20, d);
  mountainvssky = smoothstep(0, 1, mountainvssky);
  color sky = color(#1339CE);
  color whitesky = color(#7993F0);
  float whiteskyfactor = noise(x*.005, y*.01, seed);
  whiteskyfactor -= .6;
  whiteskyfactor = smoothstep(-.1, .1, whiteskyfactor);
  sky = lerpColor(sky, whitesky, whiteskyfactor);
  color star = color(#EDED8B);
  float starfactor = noise(x*.005, y*.005, seed);
  starfactor = pow(starfactor, 1.7);
  starfactor = starfactor-.5;
  starfactor = smoothstep(-.03, .05, starfactor);
  sky = lerpColor(sky, star, starfactor);
  color mountain = color(#4E5262);
  mountain = lerpColor(mountain, color(0), smoothstep(height/2, height, y));
  c = sky;
  c = lerpColor(sky, mountain, mountainvssky);
  c = lerpColor(c, color(random(255), random(255), random(255)), .02);
  return c;
}