var enemy, friendly;

var scoreCount = 0;

var gameOver = false;

var difficultyLevel = 4;

​

function setup() {

  createCanvas(500, 500);

  enemy = loadImage('invader-enemy.png');

  friendly = loadImage('invader-friendly.png');

}

​

function draw() {

  background(0);

  imageMode(CENTER);

​

  if (gameOver) {

    textAlign(CENTER);

    textSize(76);

    text("Game Over!!!", 0, height / 2, width, 80);

    return;

  }

​

  var alienToRemove = null;

​

  for (var i = 0; i < aliens.length; i++) {

    // Draw an alien

    drawAlien(aliens[i]);

​

    // Move aliens downward

    aliens[i].y += aliens[i].speed;

​

    // Remove aliens at the bottom of the screen

    if (aliens[i].y > height) {

      alienToRemove = i;

​

      if (aliens[i].type == 'enemy') {

        scoreCount = scoreCount - 2;

      }

    }

​

    // Click on alien

    var distance = dist(mouseX, mouseY, aliens[i].x, aliens[i].y);

    if (mouseIsPressed && distance < (aliens[i].size/2)) {

      alienToRemove = i;

      if (aliens[i].type == 'enemy') {

        scoreCount++;

      } else {

        scoreCount--;

      }

      // Here is the modulo :)

      if (scoreCount % 5 == 0) {

        difficultyLevel++;

        console.log(difficultyLevel);

      }

    }

  }

​

  // Remove an alien

  if (alienToRemove != null) {

    aliens.splice(alienToRemove, 1);

  }

​

  // Create new aliens at the top of the screen

  if (random(100) < difficultyLevel) {

    createAlien();

  }

​

  // Display our score

  fill(255);

  textSize(36);

  text(scoreCount, 10, 40);

​

  // Check Score

  if (scoreCount < 0) {

    gameOver = true;

  }

}

​

function drawAlien(alien) {

  if (alien.type == 'enemy') {

    image(enemy, alien.x, alien.y, alien.size, alien.size);

  } else {

    image(friendly, alien.x, alien.y, alien.size, alien.size);

  }

}

​

function createAlien() {

  var newAlien = {

    x: random(0, width),

    y: -20,

    size: 40,

    speed: random(1, 2),

    type: random(100) < 35 ? 'enemy' : 'friendly',

  };

​

  aliens.push(newAlien);

}