Spawning A Game Object:
Firstly, with a Unity project open, right-click in the Hierarchy and create a 3D object/Capsule.
Save it as a prefab by dragging the GameObject from the Hierarchy panel into the Project panel and dropping it there. I put mine in a folder called “Prefabs”, which is a best practice. You can then delete the Capsule GameObject from the Hierarchy panel, removing it from the scene but leaving it in the project files.
Now that we’ve created a prefab of a simple capsule GameObject, let’s create the script that will instantiate it when the game is running. Right-click in the project panel and choose “Create/C# Script”, then name it. Since I’m creating a space shooter, I’ll call mine “PlayerGun”.
Open the script in your code editor, and delete the Start method.
First, we should create a variable to store the GameObject that we want to instantiate. Inside the class, at the top, create a GameObject variable to hold the Capsule prefab.
Now in the Update method, I want to define when the Laser Bolt will be instantiated. I’ll use “Input.GetButtonDown(“Fire1”)” since it is convenient to use Unity’s Input Manager, where “Fire1” is already assigned to the Mouse 0 button (left click). I could alternatively use “Input.GetKeyDown(KeyCode.Mouse0)”, but that is hard-coded and harder for the player to change.
For cleanliness, I’ll make a seperate function to actually spawn the Laser Bolt prefab.
Now I’m almost at the stage of instantiating. Unity’s Object.Instantiate method has a few different versions I could use, but I want the one that takes
- An Object (my Laser Bolt prefab),
- A Vector3 spawn position, and
- A Quaternion spawn rotation.
To avoid physics collision issues, I’ll create a spawn position that is near, but not on, the player’s current position:
Call the Instantiate method and pass in the _capsule variable, the spawnPoint variable, and set it’s rotation to (0,0,0,0), or “Quaternion.identity”.
Now if I save and add this script as a component to the Player GameObject I created in the Simple Player Movement article, I get this:
Because both the Player and the capsule have physics colliders on them, the Player can bump into the capsules after they’ve been spawned. If I had spawned them at exactly the player’s position there would have been a high chance of them being bumped as soon as they’d been spawned, giving weird movement.
Destroying A Game Object:
Destroying a GameObject is even easier.
“obj” is the Object to be destroyed.
“t” is an optional parameter defining the delay between running this command and the Object actually being deleted in the scene. Usually this is skipped, and left at the default 0.0f (instant destruction).