let gui;
let params = {
  branches: 3, branchesMin: 1, branchesMax: 10,
  multiplier: 0.8, multiplierMin: 0.05, multiplierMax: 0.95, multiplierStep: 0.05,
  
  sway: true,
  swayPerLevel: true,
  swayPerBranch: true,
  
  maxSplits: 4, maxSplitsMin: 1, maxSplitsMax: 10,
  minLength: 10, minLengthMin: 1, minLengthMax: 100,
  
  maxSplit: 3.1415/4, maxSplitMin: 0, maxSplitMax: 3.1415, maxSplitStep: 0.01
}

function setup() {
  createCanvas(400, 400);
  
  gui = createGuiPanel('params');
  gui.addObject(params);
  gui.setPosition(420, 0);
}

function draw() {
  background(255);
  
  function step(length, count, index) {
    let left = params.maxSplit;
    let right = params.maxSplit;
    
    if (params.sway) {
      let a = frameCount / 100.0;
      let b = params.swayPerLevel ? count : 0;
      let c = params.swayPerBranch ? index : 0;

      left = noise(a, 0, b + c) * params.maxSplit;
      right = noise(a, 1, b + c) * params.maxSplit;
    }

    let each = (left + right) / (params.branches - 1);
    
    push();
    
    stroke(0);
    fill(0);
    line(0, 0, 0, length);
    
    translate(0, length);
    
    if (count <= params.maxSplits && length > params.minLength) {
      // Branches if we have more splits and enough length left
      rotate(-left);
      step(length * params.multiplier, count + 1, 0);
      
      for (let i = 0; i < params.branches - 1; i++) {
        rotate(each);
        step(length * params.multiplier, count + 1, i + 1);
      }
    } else {
      // Otherwise, leaves
      fill(0, 255, 0);
      circle(0, 0, 20);
    }
    
    pop();
  }
  
  translate(200, 400);
  rotate(PI);
  step(100, 1);
}