Hi there!
I come from a fairly solid C# background, but I’m still working out how Unity scripts play with the Unity ecosystem at large.
I’m building myself a simple weapon system. The player control script I have has an IWeaponBehavior that tells the script if the weapon can shoot, and allows the script to shoot the weapon.
Inside of an implementation of IWeaponBehavior, I want to Instantiate a bullet prefab, position it, and send it on its way when its Shoot method is called. Roughly, I have the following:
public class PistolBehavior : MonoBehaviour, IWeaponBehavior
{
float timeSinceLastShot;
float fireDelay = 1;
public GameObject bulletPrefab;
public int ShotSpeed { get; private set; } = 5;
public bool CanShoot()
{
return timeSinceLastShot + fireDelay < Time.time;
}
public void Shoot(Vector2 firePoint, Transform aim, float fireOffset)
{
if (!CanShoot())
return;
var aimAngle = aim.eulerAngles.z * Mathf.Deg2Rad;
var fireDirection = new Vector2(Mathf.Cos(aimAngle), Mathf.Sin(aimAngle));
var bullet = Instantiate(bulletPrefab, firePoint + (fireDirection * fireOffset), Quaternion.identity);
bullet.GetComponent<Rigidbody2D>().velocity = fireDirection * ShotSpeed;
timeSinceLastShot = Time.time;
}
}
And in the Unity Inspector when I select the PistolBehavior script, I have this, where I’ve inserted my bullet prefab:
However when I run the game and attempt to shoot, I get the error message
“ArgumentException: The Object you want to instantiate is null.”, referencing the point where I instantiate my bullet.
I’ve looked around and have seen other suggestions, such as loading prefabs from a Resources folder, but attempting to do so that way also gave me the same error.
What’s the “right” way to do this? Coming from a non-game-programming background, my setup seems reasonable to me. Am I barking up the wrong tree? Is there a “Unity” way to do this?
