Advanced Unity Sushi

Loosing Lives

Let’s finish up the code in the “Collisions” script.

You are going to create an array.

What’s an array?

An array is a collection of elements (of the same type) that can be accessed with an index.

In C# programming an index starts at 0. So, the first item in an array will be the 0th element. An array with three elements in it will have elements 0, 1, and 2.

You will create an array of GameObjects. There are three hearts for each player, so you can use an array because they are all the same type (type GameObject).

Declaring an array is easy, all you need to do is add square brackets to the end of a data type (example: int[] numbers;).

  • Look at the top of the “Collisions” script, where all the variables are declared. You should see the hearts array declared. You can tell it is an array because of the []: 
    private GameObject[] hearts;

Now you need to initialise the array.

What does initialise mean?

Initialising is when you create an array. The number of elements in a C# array need to be known when you create the array.

To do this you need to use the new keyword again. You need to know the size of an array when it is created, and you know it should be three because their are three hearts!

  • So, add this line to Start() under // Array declaration, which will initialize your array with 3 elements: hearts = new GameObject[3];.

Note: Whatever number you put where the three is will change the size of an array. so hearts = new GameObject[10]; will create an array with ten elements.

Now you need to assign values to each element of an array. To access a specific element you use this syntax: array[x] where x is the element you want to access. Remember! Arrays are 0 indexed so the first element will be array[0]!

  • Add these lines of code under hearts = new GameObject[3];:
hearts[0] = GameObject.Find(animal + "Heart3");
hearts[1] = GameObject.Find(animal + "Heart2");
hearts[2] = GameObject.Find(animal + "Heart1");

Now if you want to make the player lose a heart, all you need to do is delete the number in the array that you want. To know which heart to delete I’ve given you a lives counter variable. Every time the player falls off the screen the lives counter will subtract 1. All you need to do is Destroy the array element that is a heart.

  • Add this line of code into the OnCollisionEnter2D(Collision col) function:
Destroy(hearts[lives]);

Now you can run the game and the lives will disappear!

  • Try it out now.
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