Vertigo II

var n,s0,s,s_coef,a, twists;

​

function setup() {

  createCanvas(600, 600);

  a = 255;

  s0 = width*.50  ;

  s = s0;

  n = 250;

  s_coef = 1.0;

  twists = 3.65;

  var mainColor = color(233,86,35);

  background(mainColor);

  smooth(8);

}

​

function draw() {

  if (frameCount >= n) {

    noLoop();

    //save("vertigoII.png");

  }

​

  translate(width/2, height / 2);

​

  noFill();

  strokeWeight(2);

  stroke(255, 255, 255, a);

  ellipse(0, 0, s, s );

  s+=s_coef;

  a-=.8;

​

  //draw  

  if(frameCount==1) {

    //inner circle

    noStroke();

    fill(33, 52, 52, 255);

    ellipse(0, 0, s0*.63, s0*.63);

  }

  //the spiral

  fill(77, 166, 158);

  stroke(77, 166, 158);

  strokeWeight(.5);

  beginShape(TRIANGLE_STRIP);

  for (var i=frameCount; i<=frameCount+1 && i < n; i++) {

    let angle = HALF_PI +  i/n  * twists * TWO_PI;

    let r1 = 10 +  angle*2.5 ;

    let r2 = 15 +  angle*2.55;

    r1 *= 1.02 + 0.03 * (1. - 2 * noise(angle*10));

    r2 *= 1.03 + 0.03 * (1. - 2 * noise(angle*5 + 34389));

    vertex(r1 * cos(angle), r1 * sin(angle));

    vertex(r2 * cos(angle), r2 * sin(angle));

  }

  endShape();   

​

  //small circle

  fill(255,pow(a,2));noStroke();

  ellipse(height/9, -height/9, (s0-s)*.2 , (s0-s)*.2);

}