MiniGame2: Pizza Carnage

This game consists of eliminating waves of aliens by throwing pieces of pizza at them.

You will learn to:

Create a spawner

Use randomness

Create and use Prefabs

Detect collisions

Model a pizza and an alien with their colliders

Scene Layout

Open the Assets folder named MiniGames

Inside this folder, create a new Scene named: Pizza Carnage

Create a ground of 10mx10m, apply a green color

Create a capsule to represent the player

Create 3 objects to represent the aliens

Player control

Create a controller script for the player:

Player can move left and right using the arrow keys

Add a test to prevent the player from going off the ground

Pizza

Without a doubt, the most interesting part of this project is coming up: modeling a slice of pizza in 3D

Add a script to make the pizza move at a speed of 10m/s in the direction of the aliens

Prefab

The player will throw pizza slices to the aliens, so we need to reuse the same slice of pizza multiple times. For this, we transform our 3D pizza slice into a prefab.

Drag an drop your pizza slice into the MiniGames folder

Delete the pizza from the scene

Enter Play mode

Drag and drop the pizza slice into the hierarchy window, this will instantiate the pizza prefab in real time

Exit Play mode

Firing pizza

Go back in the player controller script

Add a new variable: public GameObject pizzaSlice

Link this variable to your prefab
In the update() function, detect when the spacebar is pressed
if ( Input.GetKeyDown(KeyCode.Space) )
If we look at the documentation:

We notice a version that is interesting:

First parameter: the prefab we want to instantiate

Its position

Its rotation

Instantiate a prefab when spacebar is pressed

At the player position

Using the rotation transform of the prefab

Self-destruction

In order to improve game performance, we need to destroy projectiles when they go out of bounds.

When a pizza slice if far away (> 10m)
Destroy the current object using:
Destroy(gameObject);

Alien Spawner

Transform you three aliens into prefab

Delete aliens from the scene

Our spawn manager script will be associated to a hidden GameObject:

Right click in the Hierarchy windows and select: Create Empty

Rename this object to spawnmanager

Create a script and attach it to the spawn manager
Edit the script and add an array of prefabs as a public member:
public GameObject[] alienPrefabs;
Select the spawnmanager object

In the Inspector window, set the size of the array to 3

Drag and drop the 3 alien prefabs to fill the array
Create a function Spawn() in the Spawnmanager script
Randomly choose the alien prefabs
int randomValue = Random.Range(0, 3);  // generate a random integer number between 0 and 2
Make the alien appears in front of the player by randomly choosing its location

Call the Spawn() function from the Start() function
Help in case nothing works
void RandomSpawn()
{
        int r = Random.Range(0, 3);

        Vector3 V = alienPrefabs[r].transform.position;
        V.z = Random.Range(-6, 6);
        Instantiate(alienPrefabs[r], V, alienPrefabs[r].transform.rotation);
}
Enter Play mode:
Remove the Spawn() function from the Start() function
We now spawn the aliens on a timer
void Start()
{
        float startDelay = 2;
        float spawnInterval = 3;
        InvokeRepeating("RandomSpawn",  startDelay, spawnInterval);
}

Collision

Double click on the pizza prefab

Add a box collider component

Click on Edit collider

Select scale Tool and reduce the collider to fit the shape of the pizza

Go back to the scene

Create a new script for aliens and associate this script to each alien prefabs
This script must destroy the alien and also the pizza
Destroy(gameObject);
Destroy(other.gameObject);
Configure the collision system so that the game works properly

Configure colliders if needed

Select the right function for collision management

Here is the final version of the game: