// Daniel Shiffman

// http://natureofcode.com

​

// Stochastic Tree

// Renders a simple tree-like structure via recursion

// Angles and number of branches are random

​

function setup() {

  createCanvas(640, 240);

  frameRate(1);

}

​

function draw() {

  background(255);

​

  stroke(0);

  push();

  // Start the tree from the bottom of the screen

  translate(width / 2, height);

  strokeWeight(2);

  // Start the recursive branching!

  branch(80);

  pop();

}

​

function branch(length) {

  // Draw the actual branch

  line(0, 0, 0, -length);

  // Move along to end

  translate(0, -length);

​

  // Each branch will be 2/3rds the size of the previous one

  length *= 0.67;

​

  // All recursive functions must have an exit condition!!!!

  // Here, ours is when the length of the branch is 2 pixels or less

  if (length > 2) {

    // A random number of branches

    let n = Math.floor(random(1, 4));

    for (let i = 0; i < n; i++) {

      // Picking a random angle

      let angle = random(-PI / 2, PI / 2);

      push(); // Save the current state of transformation (i.e. where are we now)

      rotate(angle); // Rotate by theta

      branch(length); // Ok, now call myself to branch again

      pop(); // Whenever we get back here, we "pop" in order to restore the previous matrix state

    }

  }

}

​