koobas.hobune.stream
Spawning a Ball going forward every 5 seconds error, help!
Alright so I made this script:
using UnityEngine;
using System.Collections;
public class CannonShots : MonoBehaviour {
public Transform ballPos;
public Rigidbody Ball;
public float timeMin = 1;
public float timeMax = 3;
public float forceAmount = 1500;
void SpawnBall()
{
Rigidbody ballRigid;
ballRigid = Instantiate(Ball, ballPos.position, ballPos.rotation) as Rigidbody;
ballRigid.AddForce(ballPos.forward * forceAmount);
}
void Start() {
float timeToSpawn = Random.Range(timeMin, timeMax);
InvokeRepeating("SpawnBall", timeToSpawn, timeToSpawn);
}
}
An error pops out saying NullReferenceException: Object reference not set to an instance of an object CannonShots.SpawnBall () (at Assets/MyAssets/Scripts/CannonShots.cs:16) . I know what this error means but I can't seem to figure out how to fix it. So can somebody please help me and explain what the error was and correct it? Thanks!
The following fixes your error(s) and adds some debugging
void SpawnBall()
{
Rigidbody ballRigid;
if ((Ball != null) && (ballPos != null))
{
ballRigid = Instantiate(Ball, ballPos.position, ballPos.rotation) as Rigidbody;
if (ballRigid != null)
{
ballRigid.AddForce(ballPos.forward * forceAmount);
}
else
{
debug.LogWarning("The instantiated item does not contain a Rigidbody");
}
}
else
{
if ((Ball == null)
{
debug.LogWarning("Ball has not been assigned. Please assign the Ball");
}
if (ballPos == null)
{
debug.LogWarning("ballPos has not been assigned. Please assign the ballPos");
}
}
}
Also if you want to spawn every 5 seconds you need to do it like this
InvokeRepeating("SpawnBall", timeToSpawn, 5);
Thanks, this did it! I'm really new to Unity scripting and C# overall, do you $$anonymous$$d telling me the faults in my script?
@TheReal$$anonymous$$uha
As previously mentioned to repeat the spawn every 5 seconds you needed a value of 5 as the last parameter not timeToSpawn
You were trying to instantiate an object without validating that you had a valid prefab and transform
You were trying to use ballRigid after instantiating an object without validating it
Have you assigned an object to the "ballPos and Ball" variables in the inspector ? I think the variables have a value of NULL. That is why it is called a NullReferenceException error.
Yes I have, but it still gives me the error. I can play the scene but after the object spawns it pauses the game and prints the error. I can play it if I turn off the error pause but I worry it will become an issue later on. 
