Tutorial 14 : Polishing the Game

In this, the last tutorial in the series, I will show you how to add a bit of polish to the game by adding a few key features to our game :

1. Giving the player money when he kills an enemy.
2. Removing a life when one of the enemies reaches the end of the path.

Both of these things will be implemented in the wave class, however before we make any changes to that we must first make some of the player’s properties settable!

So go to the Player class and find the Money and Lives properties and a set statement to both of them :

public int Money
{
   get { return money; }
   set { money = value; }
}
public int Lives
{
   get { return lives; }
   set { lives = value; }
}

This will allow us to make changes to these properties outside of the player class. We are now ready to add our two key features! Go to the Wave class and somewhere with the fields add a Player field :

private Player player; // A reference to the player.

Now we need to pass a reference to the player via the constructor, so change the Wave constructor to accept a player reference :

public Wave(int waveNumber, int numOfEnemies,
   Player player, Level level, Texture2D enemyTexture)
{
    this.waveNumber = waveNumber;
    this.numOfEnemies = numOfEnemies;

    this.player = player; // Reference the player.
    this.level = level;

   this.enemyTexture = enemyTexture;
}

Now that we have a stored reference to the player, find the Update method and in particular the if statement that check’s if an enemy is dead but still has health (ergo the enemy is at the end), and in this if statement add the code to remove a life from the player :

if (enemy.IsDead)
{
   if (enemy.CurrentHealth > 0) // Enemy is at the end
   {
       enemyAtEnd = true;
       player.Lives -= 1;
   }

Then just under that we are going to add an else statement which will be triggered if the enemy has been killed and has no health (ergo the player has killed the enemy) :

else
{
   player.Money += enemy.BountyGiven;
}

Simple huh? I can’t beleive I left it until the end to add these features in that actually make our game playable! With those changes made, that if statement should look like this :

if (enemy.IsDead)
{
   if (enemy.CurrentHealth > 0) // Enemy is at the end
   {
       enemyAtEnd = true;
       player.Lives -= 1;
   }

   else
   {
       player.Money += enemy.BountyGiven;
   }

   enemies.Remove(enemy);
   i--;
}

All that is left now is to pass the player reference to the Wave class. So go to the WaveManager class and modify the constructor so that it takes in a reference to the Player class and then passes it to the Wave class :

public WaveManager(Player player, Level level, int numberOfWaves, Texture2D enemyTexture)
{
   this.numberOfWaves = numberOfWaves;
   this.enemyTexture = enemyTexture;

   this.level = level;

   for (int i = 0; i < numberOfWaves; i++)
   {
       int initialNumerOfEnemies = 6;
       int numberModifier = (i / 6) + 1;

       // Pass the reference to the player, to the wave class.
       Wave wave = new Wave(i, initialNumerOfEnemies *
           numberModifier, player, level, enemyTexture);

       waves.Enqueue(wave);
   }

   StartNextWave();
}

Now go back to Game1 and find the LoadContent method, and in it find where we initialize the WaveManager.We need to move this initialization code to underneath where we initialize the Player and then pass in the Player to the WaveManager, like so :

Texture2D bulletTexture = Content.Load<Texture2D>("bullet");

Texture2D[] towerTextures = new Texture2D[]
{
   Content.Load<Texture2D>("arrow tower"),
   Content.Load<Texture2D>("spike tower"),
   Content.Load<Texture2D>("slow tower"),
};

player = new Player(level, towerTextures, bulletTexture);

Texture2D enemyTexture = Content.Load<Texture2D>("enemy");
waveManager = new WaveManager(player, level, 24, enemyTexture);

And we’re done!! That is the end of this series (unless people are in need of another tutorial??). So now you have a pretty solid base to work off of if you want to create your own tower defence! But don’t be tempted to think this is finished game, there is still a lot more that could be done!!

• The art is only placeholder, be creative and make your own!


• Currently there is only 1 type of enemy, how dull is that? Be creative and add new types, it is basically the same process as adding a new tower!


• Wouldn’t it be nice if enemies didn’t have to just follow a path? Let A-Star guide you...


• Add a timer that appears in between levels to let the player know how long he has before the next wave.


• Add in bonus rounds for extra gold.


• The current UI is so dull, wouldn’t it be nice if you could see some more information about each tower?

Well that’s it for me, thank you so much for the kind words, reporting bugs, and for just reading this blog!

Happy Coding!