The beginning of a Unity career - Making a spaceship mini-game

First Encounter with a Small Demo Made in Unity

Setting Up the Spaceship and Scene
Scene Layout: Place the lights in appropriate positions, pull the camera above the lights, create a new quad in the scene as a background, apply a material texture to it, drag the spaceship player into the scene, adjust its position, and add a fire effect at the tail of the spaceship.
Writing a Flight Script for the Spaceship
Player.cs:

 public float speed = 5.0f;

 float moveH = Input.GetAxis("Horizontal");
 float moveV = Input.GetAxis("Vertical");
 Vector3 move = new Vector3(moveH, 0, moveV);
 transform.Translate(speed * move * Time.deltaTime);

Drag the player.cs script onto the spaceship in Unity, making it a child object of the spaceship, so that the spaceship can be controlled with the up, down, left, and right keys on the keyboard.

Creating Bullet Flight and Prefab
Create a new game empty in the hierarchy named bolt, create a new quad as a child object of bolt, apply a material to it, adjust the bullet model's position below the spaceship, and create a flight script bolt_move.cs for the bullet:

 public float speed = 5.0f;
 // Fly in the positive direction along the z-axis
 // Update is called once per frame
 void Update () {
     transform.Translate(Vector3.forward * speed * Time.deltaTime);
}

Similarly, drag the script onto the bullet, add a rigidbody component and a capsule collider to the bullet:

Create a prefab for the bullet and place it in _prefab:
Just drag the bolt from the hierarchy to _prefab in the assets.

Bullet Firing
Create a bullet firing script and place it in the player:

// Time interval
 public float fireRate = 0.5f;
 // Fire a bullet every 0.5f
 public float nextFire = 0.0f;

 public GameObject shot;
 public Transform shotSpawn;

// Click the mouse to fire a bullet
 if (Input.GetButton("Fire1") && Time.time > nextFire)
 {
     // A series of bullets with issues appeared, need to control the firing of bullets with time
     nextFire = Time.time + fireRate;

     // Instantiate (instantiate object 'position' angle)
     Instantiate(shot, shotSpawn.position, shotSpawn.rotation);
}

Click on the player and complete the settings in the inspector:

Run it, and the bullets will fire from below the airplane.

Bullet Destruction and Collision Detection
Create a new cube named boundary, adjust its size and position to surround the spaceship.
Create a bullet destruction script destbyboundary.cs:

 void OnTriggerExit(Collider other)
 {
     Destroy(other.gameObject);
 }

Drag it into the boundary:
The relevant settings are as follows.

Run it, and the bullets will be destroyed when they fly out of the boundary.

Adding Meteor Movement and Destruction
Create a new game object named Asterial, drag a meteor model as a child object, adjust its position in the scene, and create a movement script as_move.cs for it:

 public float speed = 5.0f;

 void Update () {
     transform.Translate(Vector3.back * speed * Time.deltaTime);
 }

Add a rigidbody component and a capsule collider to it.

Also, create a prefab for it, which will appear automatically later.

Adding Tag
Add the following code to the as_move.cs script:
// Asteroid rigidbody and collider trigger, boundary has a collider trigger, it will naturally respond when the trigger enters.

 void OnTriggerEnter(Collider other)
 {
     //print(other.name);// The corresponding name is boundary, destruction is boundary, so it needs to be modified
     // Instantiate particle object
     if (other.tag == "Boundary")
         return;

     gameController.GameOver();

     Destroy(other.gameObject);
 }

Make property response modifications here.

Explosion of Meteor and Spaceship
Add the following code to as_move.cs:

 public GameObject explosion;
 public GameObject playerExplosion;

// Instantiate the explosion particle effect of the asteroid, generate particle effects at the position of the asteroid
 Instantiate(explosion, transform.position, transform.rotation);
// Instantiate the explosion effect of the player, which is the spaceship, generate particle effects at the position of the spaceship
 if (other.tag == "Player")
 {
     Instantiate(playerExplosion, other.transform.position, other.transform.rotation);
 }

 Destroy(other.gameObject);

// After the asteroid is hit, the player's score increases, and this process needs to be notified to the Text control for display
 gameController.AddScore(scoreValue);

 Destroy(gameObject);
}

Set as shown in the figure.
After running, the shooting meteor and explosion effects after collision will appear.

Batch Generation of Meteors:
Here we need to use a coroutine method:

IEnumerator WaitAndPrint()
{
 yield return new WaitForSeconds(5);
 print("WaitAndPrint" + Time.time);
}

Create a new game object named gamecontroller, and create a script gamecontroller.cs:

// Instantiate the asteroid object, position
 public GameObject hazard; // Represents the asteroid object
 public Vector3 spawnValues; // Represents the change values of the x-axis and z-axis for generation
 private Vector3 spawnPosition = Vector3.zero; // Represents the generation position
 private Quaternion spawnRotation;

 public int hazardCount = 6;

// Delay generation time
 public float spawnWait;

// Do not want the game to generate asteroids immediately at the beginning, but wait for a while, add a variable to control the waiting time
public float startWait = 1.0f;

// Code to generate asteroids
IEnumerator SpawnWaves()
{
 yield return new WaitForSeconds(startWait);
 while (true)
 {
     for (int i = 0; i < hazardCount; i++)
     {
         spawnPosition.x = Random.Range(-spawnValues.x, spawnValues.x);
         spawnPosition.z = spawnValues.z;
         spawnRotation = Quaternion.identity;
         Instantiate(hazard, spawnPosition, spawnRotation);
         yield return new WaitForSeconds(spawnWait);
     }
     yield return new WaitForSeconds(2.0f);
 }
}

void Start () {
    StartCoroutine(SpawnWaves());
}

Set the required parameters according to the scene.
Run it, and the meteors can be generated randomly.

Creating a Data Transfer Between Different Scripts, Creating a Game Lifecycle: Record Scores, Game Over, and Restart

Add the following code to as_move.cs:

private GameController gameController;
 public int scoreValue; // Increased score

 gameController.GameOver();

 void Start()
 {
     // Bind the gamecontroller defined here with the previous gamecontroller, generally speaking
     // So we first find the object with findwithtag, and then use getcomponent to find the gamecontroller script
     GameObject go = GameObject.FindWithTag("GameController"); // Note, must modify in property response

     if (go != null)
         gameController = go.GetComponent<GameController>();
     else
         Debug.Log("Cannot find the object with tag GameController");
     if (gameController == null)
         Debug.Log("Cannot find the script GameController.cs");
 }

Add the following code to gamecontroller.cs:

public Text ScoreText;
 private int score;

 public Text gameOverText;
 private bool gameOver;

 public Text restartText;
 private bool restart;

 if (gameOver)
 {
     restartText.text = "Press [R] to Restart";
     restart = true;
     break;
 }
}

// Use this for initialization
void Start () {
    score = 0;
    ScoreText.text = "Score:   " + score;
    gameOverText.text = "";
    gameOver = false;

    restartText.text = "";
    restart = false;
    StartCoroutine(SpawnWaves());
}

// Modify score
public void AddScore(int newScoreValue)
{
    score += newScoreValue;
    ScoreText.text = "Score:   " + score;
}

// Modify end properties
public void GameOver()
{
    gameOver = true;
    gameOverText.text = "Game Over";
}

void Update()
{
    if (restart)
    {
        if (Input.GetKeyDown(KeyCode.R))
            Application.LoadLevel(Application.loadedLevel);
    }
}

Set up the scene as follows:
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Thus, a small space spaceship game is basically completed.

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Run the game:

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