let snowflakes = []; // array to hold snowflake objects

​

function setup() {

  createCanvas(710, 400);

  noStroke();

  //mousePressed();

}

​

​

function draw() {

  background(0);

  //frameRate(30);

  stroke(255);

  // Let's pick an angle 0 to 90 degrees based on the mouse position

  let a = (mouseX / width) * 90;

  // Convert it to radians

  theta = radians(a);

  // Start the tree from the bottom of the screen

  translate(width/2,height);

  // Draw a line 120 pixels

  line(0,0,0,-120);

  // Move to the end of that line

  translate(0,-120);

  // Start the recursive branching!

  branch(120);

  push();

  let t = frameCount / 60; // update time

​

  // create a random number of snowflakes each frame

  for (let i = 0; i < random(5); i++) {

    snowflakes.push(new snowflake()); // append snowflake object

  }

​

  // loop through snowflakes with a for..of loop

  for (let flake of snowflakes) {

    flake.update(t); // update snowflake position

    flake.display(); // draw snowflake

  }

  pop();

​

}

​

function branch(h) {

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

  h *= 0.66;

​

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

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

  if (h > 2) {

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

    rotate(theta);   // Rotate by theta

    line(0, 0, 0, -h);  // Draw the branch

    translate(0, -h); // Move to the end of the branch

    branch(h);       // Ok, now call myself to draw two new branches!!

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

​

    // Repeat the same thing, only branch off to the "left" this time!

    push();

    rotate(-theta);

    line(0, 0, 0, -h);

    translate(0, -h);

    branch(h);

    pop();

  }

}

​

// snowflake class

function snowflake() {

  // initialize coordinates

  this.posX = 0;

  this.posY = random(-1000, 100);

  this.initialangle = random(0, 2 * PI);

  this.size = random(1, 3);

​

  // radius of snowflake spiral

  // chosen so the snowflakes are uniformly spread out in area

  this.radius = sqrt(random(pow(width, 2)));

​

  this.update = function(time) {

    // x position follows a circle

    let w = 0.1; // angular speed

    let angle = w * time + this.initialangle;

    this.posX = width/2 + this.radius * sin(angle);

​

    // different size snowflakes fall at slightly different y speeds

    this.posY += pow(this.size, 0.5);

​

    // delete snowflake if past end of screen

    if (this.posY > height) {

      let index = snowflakes.indexOf(this);

      snowflakes.splice(index, 1);

    }

  };

​

  this.display = function() {

    ellipse(this.posX, this.posY, this.size);

  };

}