During each turn, each player will select a card and use it to attack its adversary. In this section, we're going to implement how to drag and drop a sprite and how to scale its size.

First of all, you need to enable touch management, so in GameScene.m, add these lines at the end of the init method, before return self;:

// Enabling user interaction
self.userInteractionEnabled = TRUE;

We need to declare two variables to manage which card has been selected and its initial position. Add the following lines after CCLabelBMFont *_label;:

    // Declare card selected
    Card *_selectedCard;

    // Declare initial card position
    CGPoint _initialCardPosition;

We will use _selectedCard to know which card is being dragged, and _initialCardPosition will store its initial position so we can recover it if the player doesn't want to play this card.

Now implement the touchBegan method:

-(void)touchBegan:(UITouch *)touch withEvent:(UIEvent *)event {
    // Check what card has been touched...