Modes

var mode = 0;

function setup() {

  createCanvas(windowWidth, windowHeight);

  background(100);

}

function draw() {

  if(mouseIsPressed) {

    if(key == 'A') {      

      fill(255, 30);

      ellipse(mouseX, mouseY, 20, 20);

    }

    if(key == 'B') {

      line(width/2, height/2, mouseX, mouseY);

    }

    if(key == 'C') {

      var sz = random(10, 50);

      ellipse(mouseX, mouseY, sz, sz);

    }

  }

}

function keyPressed() {

  if(key == " ") {

    stroke(random(255), random(255), random(255));

  }

}