let uImg;

let tImg;

let bImgTop;

let bImgNightTop;

let bImgBottom;

let font;

let trains = [];

let time = 3;

let speed = 0;

const maxSpeed = 0.2;

let trainSpeed = 0;

let game_over = false;

let score = 0;

let high_score = 0;

let topBgOffset = 0;

let bottomBgOffset = 0;

const thresholdScore = 500;

let nightTime = false;

let beep;

let gameOverAudio;

let pauseAudio;

let playAudio;

let choo_choo;

let isPaused = false;

let isMuted = false;

let starting = false;

let timeOutId;

const debugFlag = false;    // Use during development only.

​

function preload() {

  font = loadFont('Cubano-1.ttf');

  uImg = loadImage('unicorn.png');

  tImg = loadImage('train.png');

  beep = loadSound('audioAlert.mp3');

  gameOverAudio = loadSound('game_over.mp3');

  pauseAudio = loadSound('pause.mp3');

  playAudio = loadSound('play.mp3');

  choo_choo = loadSound('train_whistle.mp3');

​

  bImgTop = loadImage('coding_train_bg_top.jpg');

  bImgBottom = loadImage('coding_train_bg_bottom.jpg');

  bImgNightTop = loadImage('night_sky.jpg');

}

​

function setup() {

  createCanvas(800, 450);

  unicorn = new Unicorn();

  nextTrainCountdown();

  if (isMuted) {

    masterVolume(0);

  }

}

​

function keyPressed() {

  if (keyCode == 27) {

    // ESCAPE Key: Pause

​

    if (!isPaused && !game_over && !starting) {

      noLoop();

      pauseAudio.play();

      clearAllTimeOuts(timeOutId + 1);

      isPaused = true;

    }

    else {

      continueGame();

    }

  }

​

  if (game_over)

    mousePressed();

​

  if (key == ' ' && isPaused) {

    continueGame();

    return;

  }

  if (key == 'm') {

    // 'M' Key: Mute SFX

    if (isMuted) {

      masterVolume(1);

    }

    else {

      masterVolume(0);

    }

    isMuted = !isMuted;

  }

​

  if (key == ' ' || keyCode == 38) {

    // 'SPACE' / 'UP ARROW KEY': Jump

    unicorn.jump(beep);

  }

}

​

function mousePressed() {  

  if (game_over) {

    trains = [];

    time = 3;

    gameStartCountdown();

    game_over = false;

    if (!starting)

      setTimeout(() => {

        nextTrainCountdown();

        score = 0;

        loop();

        clearAllTimeOuts();

      }, 2000);

  }

​

  else if (isPaused) {

    continueGame();

  }

​

  else {

    unicorn.jump(beep);

  }

}

​

function setNextTrainTimer() {

  time = floor(random(map(speed, 0, maxSpeed, 0.25, 0.5), map(speed, 0, maxSpeed, 2.5, 4)));

  console.log(trains)

}

​

function nextTrainCountdown() {

  if (!game_over && !isPaused) {

    timeOutId = setTimeout(() => {

      trains.push(new Train());

      setNextTrainTimer();

      nextTrainCountdown();

    }, time * 1000);

  }

}

​

function clearAllTimeOuts(timeout_id) {

  if (timeout_id == null)

    timeout_id = timeOutId;

  while (timeout_id--) {

    clearTimeout(timeout_id);

  }

}

​

function continueGame() {

  gameStartCountdown();

  if (!starting)

    setTimeout( () => {

      isPaused = false;

      playAudio.play();

      nextTrainCountdown();

      loop();

    }, 2000);

}

​

function gameStartCountdown() {

  if (!starting && (game_over || isPaused)) {

    w = width / 2.38;

​

    noFill();

    stroke(255);

    textSize(35);

    text("1    2    3", w, height / 1.3);

    noStroke();

    // Required to allow atleast the first occurance of code relying on `starting` to work

    setTimeout(() => {

      starting = true;

    }, 10);

​

    setTimeout(() => {

      stroke(255);

      fill(255);

      textSize(35);

      text("1", w, height / 1.3);

    }, 500);

​

    setTimeout(() => {

      stroke(0, 255, 211);

      fill(0, 255, 211);

      textSize(35);

      text("1    2", w, height / 1.3);

    }, 1000);

​

    setTimeout(() => {

      stroke(245, 220, 35);

      fill(245, 220, 35);

      textSize(35);

      text("1    2    3", w, height / 1.3);

    }, 1500);

    setTimeout(() => starting = false, 2000);

  }

}

​

function draw() {

  score = score + (0.5 * speed) + 0.1;

  speed += (score.toFixed(1) % 10 == 0) ? 0.001 : 0;

  speed = constrain(speed, 0, maxSpeed);

  topBgOffset = (topBgOffset + map(speed, 0, maxSpeed, 0.2, 1.0)) % width;

  bottomBgOffset = (bottomBgOffset + map(speed, 0, maxSpeed, 5, 10)) % width;

  image(bImgNightTop, -topBgOffset, 0);

  image(bImgNightTop, -topBgOffset + width, 0);

​

  if (score % (thresholdScore * 2) >= 0 && score % (thresholdScore * 2) <= thresholdScore) {

    nightTime = false;

    // console.log("DAY-TIME");

  }

  else if (score % (thresholdScore * 2) > thresholdScore && score % (thresholdScore * 2) <= thresholdScore * 2) {

    nightTime = true;

    // console.log("NIGHT-TIME");

  }

​

  if (parseInt(score) % thresholdScore >= 0 && (parseInt(score) % thresholdScore).toFixed(1) <= 5.1) {

    let tintVal;

    if (!nightTime) {

      tintVal = constrain(map((score % thresholdScore).toFixed(1), 0, 5.1, 0, 255), 0, 255);

    }

    else {

      tintVal = constrain(map((score % thresholdScore).toFixed(1), 0, 5.1, 255, 0), 0, 255);

    }

    tint(255, tintVal);

  }

  if (!nightTime || (parseInt(score) % thresholdScore).toFixed(1) <= 5.1) {

    image(bImgTop, -topBgOffset, 0);

    image(bImgTop, -topBgOffset + width, 0);

  }

  noTint();

  image(bImgBottom, -bottomBgOffset, 307);

  image(bImgBottom, -bottomBgOffset + width, 307);

  if (parseInt(score) % 100 == 0)

    choo_choo.play();

​

  for (let t of trains) {

    trainSpeed = map(speed, 0, maxSpeed, 12, 20);

    t.move(trainSpeed);

    t.show();

    if (unicorn.hits(t)) {

      gameOverAudio.play();

      isPaused = false;

      console.log('game over');

      game_over = true;

      background(0, 100);

      textFont("default");

      fill(245, 220, 35);

      stroke(255, 158, 77);

      textSize(25);

      text("¯\\_(ツ)_/¯", width / 2.18, height / 2.5);

      textFont(font);

      noFill();

      stroke(255);

      textSize(32);

      text("GAME OVER!", width / 2.48, height / 2);

      fill(255);

      noStroke();

      textSize(18);

      text("Tap the screen or Press any key to restart...", width / 3.9, height / 1.6);

      if (score > high_score) {

        high_score = parseInt(score);

​

        fill(0, 255, 211);

        textSize(25);

        text("New Highscore!!", width / 2.53, 60);

      }

      speed = 0;

      noLoop();

    }

    if (t.offscreen()) {

      trains.splice(0, 1);  // Remove first occurance; (Most likely offscreen)

    }

  }

  textFont(font);

  noStroke();

  fill(198, 105, 235);

  stroke(178, 56, 227);

  if (game_over || nightTime) {

    fill(245, 220, 35);

    stroke(255, 158, 77);

  }

  if (!game_over) {

    textSize(18);

    text(`ESC: ${(!isPaused) ? "Pause" : "Continue"}`, 20, 25);

    text(`M:    ${(!isMuted) ? "Mute SFX" : "Unmute SFX"}`, 20, 50);

  }

  textSize(18);

  text("Score", width - 100, 25);

  text(parseInt(score), width - 100, 50);

  text("Hi Score", width - 200, 25);

  text(high_score, width - 200, 50);

  if (debugFlag) {

    noStroke();

    textSize(15);

    text("DEBUG", width / 2.08, 20);

​

    textSize(15);

    text("Speed = " + speed, 20, 85);

    textSize(15);

    text("Train Speed = " + trainSpeed, 20, 100);

​

    textSize(15);

    text("Top BG Offset = " + topBgOffset.toFixed(10).toString().padStart(14, '0'), 20, 115);

​

    textSize(15);

    text("Bottom BG Offset = " + bottomBgOffset.toFixed(10).toString().padStart(14, '0'), 20, 130);

    // Manual Change Reqd.

    textSize(15);

    text(`Top BG Velocity = ${map(speed, 0, maxSpeed, 0.2, 1.0)} per Frame`, 20, 145);

​

    // Manual Change Reqd.

    textSize(15);

    text(`Bottom BG Velocity = ${map(speed, 0, maxSpeed, 5, 10)} per Frame`, 20, 160);

​

    // Manual Change Reqd.

    textSize(15);

    text(`Min Time Gap = ${map(speed, 0, maxSpeed, 0.25, 0.5)} secs`, 20, 175);

​

    // Manual Change Reqd.

    textSize(15);

    text(`Max Time Gap = ${map(speed, 0, maxSpeed, 2.5, 4)} secs`, 20, 190);

  }

  if (isPaused) {

    background(0, 100);

    fill(0, 255, 211);

    stroke(0, 255, 211);

    textSize(25);

    strokeWeight(5);

    text("|  |", width / 2.04, height / 2.7);

    strokeWeight(1);

    noFill();

    stroke(255);

    textSize(32);

    text("PAUSED!", width / 2.3, height / 2);

​

    fill(255);

    noStroke();

    textSize(18);

    text("Tap the screen or Press 'ESC'/'SPACE' to continue...", width / 4.5, height / 1.6);

  }

​

  unicorn.show();

  unicorn.move();

}

​