public GameScreen(Game game, SpriteSheet spriteSheet)
: base(game, spriteSheet)
{
pipeUp = SpriteSheet.Sprites[FlappyBirdSprites.pipe_up];
pipeDown = SpriteSheet.Sprites[FlappyBirdSprites.pipe_down];
score = new SpriteNumber(SpriteSheet.Sprites, FlappyBirdSprites.Formats.font);
pipes = new List <SKPoint>();
pipeWidth = Math.Max(pipeUp.Size.Width, pipeDown.Size.Width);
tutorial = new TutorialOverlay(game, spriteSheet);
gameOver = new GameOverOverlay(game, spriteSheet);
whiteFlash = new Animator();
whiteFlashPaint = new SKPaint();
whiteFlashPaint.Color = SKColors.Transparent;
}