Intermediate Unity Sushi

Creating Lasers

  • Inside the Scripts folder, create a new folder called Lasers. Now create two C# scripts: CreateLasers and DestroyLaser.

Firing lasers

  • Start with creating a laser. Attach the CreateLasers script to the Lasers GameObject. Add this code:
public GameObject laser;
public GameObject player;

void Update(){
    if (Input.GetMouseButtonDown(0))
    {
    Vector3 createPosition = player.transform.position;
    createPosition.y += 1f;
    // Create a laser clone
    GameObject laserClone = Instantiate(laser, createPosition, transform.rotation);
    }
}

What does the code do?

Notice that this looks similar to the obstacle that you just created. You’ve added an if statement so that this block of code only runs when the player left clicks.

player.transform.location is the center of the player GameObject, your spaceship. You don’t wan’t to create the laser inside of the spaceship, and adding 1 to the y value will prevent that.

You might not have seen this operator here before: pos.y += 1f;. Coders are pretty lazy and using these “shorthand” operators allow us to shorten code. a += b is the same as ` a = a + b`, but notice how much shorter the first one is! Here is a list of the shorthand operators in C#: dojo.soy/CSharpShortOps.

With this code, left-clicking the mouse is the trigger for firing a laser.

  • If you want, try to allow the player to fire a laser when they press a different button like the spacebar. You can find other input options here: dojo.soy/CSharpInputs.

  • Now, just attach the “Laser” Prefab and “Player” GameObject to the script.

Getting the lasers to move

  • Go back to the “CreateLasers” script and above Start() add
public float laserSpeed;
  • Add the following code to the end of Update() (so, underneath the line GameObject laserClone = Instantiate(laser, createPosition, transform.rotation);):
// Make the clone move
Rigidbody laserRB = laserClone.GetComponent<Rigidbody>();
laserRB.velocity = transform.up * laserSpeed;

What does the code do?

Just like with the asteroids, you need to access the laser’s Rigidbody to set its velocity.

The code laserClone.GetComponent<Rigidbody>() gets the Rigidbody so that you can then set the velocity on the next line.

  • Back in Unity, click on the “Laser” object in the Hierarchy and set “laserSpeed” to 20 in the script section of the Inspector.

  • Try out your lasers now!

Adding sound

In movies, lasers make sounds, right? Let’s add a sound to this laser.

  • Click on the laser in the “Prefabs” folder and add an AudioSource component (Component > Audio > Audio Source).

  • From the “Audio” folder in “Assets”, drag “LaserSound” into the Audio Clip property in the “Laser” prefab Inspector.

Drag the sound into the Audio Clip box

If you run the game you can test the lasers out!

< Next