Unable to get new unity particle system code working post update - unity3d

I used to have the following particle system that worked.
// In the inspector I drag in the leaf particle system.
public ParticleSystem LeafStormParticleSystem;
private IEnumerator activate(float ActivateFor) {
//Change number of particles to 150
LeafStormParticleSystem.maxParticles = 150;
// LeafStormParticleSystem.
var newEmission = LeafStormParticleSystem.emission;
var rate = newEmission.rate;
rate.constantMin = 20;
rate.constantMax = 21;
newEmission.rate = rate;
Now as you can probably tell, this simple increases the number of particles. Now, this used to work and probably doesn't because of the new particle system I keep reading about.
However on this new particle system I have a question and issues getting it to work.
Issue
Correct me if i'm wrong but the particle system is defined as follows
void Start()
{
ParticleSystem ps = GetComponent<ParticleSystem>();
var main = ps.main;
main.startDelay = 5.0f;
main.startLifetime = 2.0f;
}
Now if I have 3 particle systems, how do I specify which one i'm referring to? Since I cant define it as public and drag the particle system to it in the editor anymore?
Issue B
Now i tried following what unity said in their forums and did the following
ParticleSystem ps = GetComponent<ParticleSystem>();
var main = ps.main;
main.maxParticles = 150;
// LeafStormParticleSystem.maxParticles = 150;
do not create your own module instances, get them from a ParticleSystem instance UnityEngine.ParticleSystem+MainModule.set_maxParticle
Any help with Issues A and B will be appreciated.
Thank you

Issue A
Only one ParticleSystem component can be attached to any one GameObject at a time. Sub-ParticleSystems must therefore be attached to separate GameObjects too (generally children of the GameObject holding the first ParticleSystem), which can be dropped directly onto public fields.
public ParticleSystem LeafStormParticleSystem;
void Start ()
{
if (LeafStormParticleSystem != null)
{
var main = LeafStormParticleSystem.main;
main.maxParticles = 150;
}
}
Issue B
Your code looks fine, however a critical part of the error message was missing; NullReferenceException which is telling you that a reference in your code is equal to NULL. In your case, that reference would be the ps variable used to store the ParticleSystem reference, which is either a consequence of not attaching this script to the GameObject holding your ParticleSystem or simply that you have no ParticleSystem attached at all. In either case, make sure both script and ParticleSystem are attached to the same GameObject and check your references like so;
void Start ()
{
ParticleSystem ps = GetComponent<ParticleSystem>();
if (ps != null)
{
var main = ps.main;
main.maxParticles = 150;
}
}

Related

Instantiate GameObjects and change Material when it hits on the ground

There is a code for instantiate cube into the list and change a Material of each clone when it hits on the ground
The following code works but not in Real-Time. Update function works like a Start function for a Foreach method
How to get a value of item.transform.position.y in the Update function Real-Time?
public GameObject cubePrefab;
public Material RedMat;
public float GroudLevel = 0.5f;
void Update()
{
if (Input.GetMouseButtonDown(0))
{
List<GameObject> cloneList = new List<GameObject>();
//instantiate clones into the list
for (int i = 0; i < 10; i++)
{
var clone = Instantiate (cubePrefab,new Vector3(Random.Range(-3f, 3f),
Random.Range(4f, 10.5f),Random.Range(-3f, 3f)), Quaternion.identity);
cloneList.Add(clone);
}
//if clone is grounded change a Material for each clone
foreach (var item in cloneList)
{
//Debug.Log(item.transform.position.y);
//check if clone is on the ground
if(item.transform.position.y < GroudLevel)
{
item.GetComponent<Renderer>().material = RedMat;
}
}
}
}
There is a screenshot for a GroudLevel = 7
The reason this function isn't working is because the pivot (transform.position) of your item is always in the center of the object. This isn't something you can change in Unity (nor would you necessarily want to).
On top of this, you're checking if the item is under the ground, and not on it when you use < insteaad of <=, because the position needs to be less than groundLevel to return true.
There are several solutions here.
The simplest would involve moving all of this logic to an OnCollisionEnter or OnTriggerEnter method. For more information on this, check the Unity documentation.
Another solution would be to find a way tthe size of the object, divide it by two, and check if
item.transform.position - halfSize <= groundLevel;
This seems really cumbersome and overly complex, however. You'd be better off using Unity's built-in collision system, unless you have a reason not to.

Unity ParticleSystem collidesWith

I am trying to change collidesWith paramater of an particle system inside of a script but i am getting this error:
Error CS1612 Cannot modify the return
value of 'ParticleSystem.collision'
because it is not a variable
My Code:
GameObject ammo; //Game object with ParticleSystem on it
public LayerMask desiredLayers;
private void Start()
{
ammo.GetComponent<ParticleSystem>().collision.collidesWith = desiredLayers;
}
Now my question is what is the correct way to change the layers of a particle system collide with.
Okay i figure it out, apparently ParticleSystem is a property.
And Unity have something special for ParticleSystem which uses Pointers so following code solved my problem:
var collidesWith = ammo.GetComponent<ParticleSystem>().collision.collidesWith;
collidesWith = desiredLayers;

Unity3D: Setting AudioSource volume dynamically using AnimationCurve

Newcomer to Unity here. For this project, I am reading in an outside AnimationCurve, and attempting to use it to adjust the volume of my GameObject every frame in the Update function. I have found documentation on how to access the volume of my AudioSource GameObject component (this is working), but I can't figure out how to use my evaluated curve to update the volume.
Screencap with imported AnimationCurve and evaluated values
My cs script is included below. Sorry if it's a bit opaque. This is for a neuroscience experiment, so I need to carefully control the animation curves. It reads in times and values (stored in currentCurveData) used to add keyframes to the new AnimationCurve (curveThisTrl) in the SetAnimationFrames() function.
The key part is in Update(). The initial tone.volume is correct, so I know it's reading that property from the GameObject. I can also see the correct curve values coming through in the Debug Log every frame, so I know the curve evaluation is working. It's just not changing the volume property of the GameObject as I want it to.
Hopefully this is enough information to spot a problem, but if not I can try to provide a test AnimationCurve for reproducibility. Thanks in advance for any help.
public class AnimationControl : MonoBehaviour {
private DataController dataControllerRef;
private CurveDataSingleTrial currentCurveData;
private float initTime;
public AnimationCurve curveThisTrl;
AudioSource tone;
void Awake()
{
initTime = Time.time;
}
// Use this for initialization
void Start ()
{
// Get references to key objects in scene
dataControllerRef = FindObjectOfType<DataController>(); // Has values from JSON
tone = GetComponent<AudioSource>();
Debug.Log(tone.volume);
// query the DataController for the current curve data
currentCurveData = dataControllerRef.GetCurrentCurveData();
SetAnimationFrames();
}
void SetAnimationFrames()
{
int numKeyFrames = currentCurveData.keyframeTimes.Length;
for (int c = 0; c < numKeyFrames; c++)
{
curveThisTrl.AddKey(currentCurveData.keyframeTimes[c], currentCurveData.keyframeVals[c]);
}
}
// Update is called once per frame
void Update ()
{
float currTime = Time.time - initTime;
tone.volume = curveThisTrl.Evaluate(currTime);
Debug.Log(tone.volume);
}
}

how to randomly initialize particles system in different places of scene in unity3d

I recently tried asking this question but I realized it was not a sufficient question. In my game the player is a fire fighter learner and i want to broke out fire randomly in my game (like not predictable by player), but i did not know how to implement this.
So far i have done this but nothing goes good.(I have a empty object called t in unity which have 3 to 5 particles systems, and all are set to dont awake at start)
code is here :
using UnityEngine;
using System.Collections;
public class Example : MonoBehaviour {
public ParticleSystem[] particles;
public int numOn = 3;
public int j;
void Start() {
for (int i = 0; i < particles.Length - 1; i++) {
j = Random.Range(i + 1, particles.Length - 1);
ParticleSystem t = particles[j];
particles[j] = particles[i];
particles[i] = t;
}
for (j = 0; j < numOn; j++ )
{
particles[j].Play();
}
}
}
help will be appreciated :-)
You could try using prefabs. Create a game object in the editor that has any particle systems and scripts your fire objects need. Once it's good, drag the object from the hierarchy into your project. This will create a prefab (you can now remove it from the scene). Now, on your spawning script, add a field of type GameObject and drag the prefab you made before into it. Now, when you need to create one, just call Instantiate(prefabVar) to create a copy of your prefab.
Edit:
For your specific case, since you only want one fire to be instantiated in a random location, you could have your spawning script look something like this:
public Transform[] SpawnPoints;
public GameObject FirePrefab;
void Start() {
Transform selectedSpawnPoint = SpawnPoints[(int)Random.Range(0, SpawnPoints.Count - 1)];
Instantiate(FirePrefab, selectedSpawnPoint.position, selectedSpawnPoint.rotation);
}
This solution would allow for you to potentially spawn more than one fire object if you needed. An alternative would be if you will only ever have exactly one fire object in the scene at all. Instead of instantiating from a prefab, the object is already in the scene and you just move it to one of your spawn points at the start of the scene. An example script on the fire object itself:
public Transform[] SpawnPoints;
void Start() {
Transform selectedSpawnPoint = SpawnPoints[(int)Random.Range(0, SpawnPoints.Count - 1)];
transform.position = selectedSpawnPoint.position;
transform.rotation = selectedSpawnPoint.rotation;
}

Unity: getting NullReferenceException using javascript

I'm a newby in Unity and I'm following the first Unity tutorial. When i try to run my first script i get this error:
NullReferenceException: Object reference not set to an instance of an object
Here is my script:
#pragma strict
private var rb:Rigidbody;
private var player:GameObject;
function start() {
player = GameObject.Find("Player");
rb = player.GetComponent(Rigidbody);
}
function FixedUpdate() {
var moveHorizontal:float = Input.GetAxis("Horizontal");
var moveVertical:float = Input.GetAxis("Vertical");
var movement:Vector3 = new Vector3(moveHorizontal , 0.0f , moveVertical);
rb.AddForce(movement);
}
I have no idea what am I doing wrong.
UPDATE:
Here is my scene:
UPDATE:
I've put print in both functions, and it seems like start is not being called at all, and that is why my variable is not being initialized. Any idea?
I would remove the declaration
private var rb:Rigidbody;
because it seems that your script is trying to access the declared Rigidbody (that stills not initialized, so it's null), and not the object's real one.
Side note: seems that, from Unity 5.3.3, you have to do:
player.GetComponent.<Rigidbody>();
(from here)
It seems your gameobject doesn't have Rigidbody component attached to it and variable rb is null after rb = GetComponent(Rigidbody);
You should take advantage of "Unity way" to reference variables. I mean, your player and rb attributes must be public and you just drag into it your gameobject from hierarchy to your attribute on inspector.
If you still want to do it private, for some good reason, just change player = GameObject.Find("Player"); for player = GameObject.FindWithTag("Player"); and your null reference probably will be solved.
So finally after a few hours, I got it. The problem was that start function should be upper case Start. Since it was lowercase, it wasn't called and rb was not initialized.
And here is the final script:
#pragma strict
private var rb:Rigidbody;
function Start() {
rb = GetComponent(Rigidbody);
}
function FixedUpdate() {
var moveHorizontal:float = Input.GetAxis("Horizontal");
var moveVertical:float = Input.GetAxis("Vertical");
var movement:Vector3 = new Vector3(moveHorizontal , 0.0f , moveVertical);
rb.AddForce(movement);
}