jobData | Contains the particle properties. |
Implement this method to access and modify particle properties.
You can use the following script to attract particles to a supplied position.
using System; using Unity.Collections; using UnityEngine; using UnityEngine.ParticleSystemJobs;
public class ParticleJob : MonoBehaviour { public float effectRange = 2.0f; public float effectStrength = 1.0f; public float oscillationSpeed = 12.0f; public bool useJobSystem = false;
private float oscillationPhase;
private ParticleSystem ps; private UpdateParticlesJob job = new UpdateParticlesJob(); private ParticleSystem.Particle[] mainThreadParticles;
private static float Remap(float x, float x1, float x2, float y1, float y2) { var m = (y2 - y1) / (x2 - x1); var c = y1 - m * x1;
return m * x + c; }
private static Vector3 CalculateVelocity(ref UpdateParticlesJob job, Vector3 delta) { float attraction = job.effectStrength / job.effectRangeSqr; return delta.normalized * attraction; }
private static Color32 CalculateColor(ref UpdateParticlesJob job, Vector3 delta, Color32 srcColor, UInt32 seed) { var targetColor = new Color32((byte)(seed >> 24), (byte)(seed >> 16), (byte)(seed >> 8), srcColor.a); float lerpAmount = delta.magnitude * job.inverseEffectRange; lerpAmount = lerpAmount * 0.25f + 0.75f; return Color32.Lerp(targetColor, srcColor, lerpAmount); }
void Start() { ps = GetComponent<ParticleSystem>(); oscillationPhase = UnityEngine.Random.Range(0.0f, Mathf.PI * 2.0f); }
void Update() { Vector2 mouse = Input.mousePosition; job.effectPosition = Camera.main.ScreenToWorldPoint(new Vector3(mouse.x, mouse.y, -Camera.main.transform.position.z)); job.effectRangeSqr = effectRange * effectRange; job.effectStrength = effectStrength * Remap(Mathf.Sin(oscillationPhase + Time.time * oscillationSpeed), -1, 1, -1, 0.5f); job.inverseEffectRange = (1.0f / effectRange);
if (!useJobSystem) { if (mainThreadParticles == null) mainThreadParticles = new ParticleSystem.Particle[ps.main.maxParticles];
var count = ps.GetParticles(mainThreadParticles); for (int i = 0; i < count; i++) { Vector3 position = mainThreadParticles[i].position; Vector3 delta = position - job.effectPosition; if (delta.sqrMagnitude < job.effectRangeSqr) { mainThreadParticles[i].velocity += CalculateVelocity(ref job, delta); mainThreadParticles[i].startColor = CalculateColor(ref job, delta, mainThreadParticles[i].startColor, mainThreadParticles[i].randomSeed); } } ps.SetParticles(mainThreadParticles, count); } }
void OnParticleUpdateJobScheduled() { if (useJobSystem) job.Schedule(ps); }
struct UpdateParticlesJob : IJobParticleSystem { [ReadOnly] public Vector3 effectPosition;
[ReadOnly] public float effectRangeSqr;
[ReadOnly] public float effectStrength;
[ReadOnly] public float inverseEffectRange;
public void Execute(ParticleSystemJobData particles) { var positionsX = particles.positions.x; var positionsY = particles.positions.y; var positionsZ = particles.positions.z;
var velocitiesX = particles.velocities.x; var velocitiesY = particles.velocities.y; var velocitiesZ = particles.velocities.z;
var colors = particles.startColors;
var randomSeeds = particles.randomSeeds;
for (int i = 0; i < particles.count; i++) { Vector3 position = new Vector3(positionsX[i], positionsY[i], positionsZ[i]); Vector3 delta = (position - effectPosition); if (delta.sqrMagnitude < effectRangeSqr) { Vector3 velocity = CalculateVelocity(ref this, delta);
velocitiesX[i] += velocity.x; velocitiesY[i] += velocity.y; velocitiesZ[i] += velocity.z;
colors[i] = CalculateColor(ref this, delta, colors[i], randomSeeds[i]); } } } } }
You can use the following script with the above example to supply the mouse position as the point to attract particles towards.
using UnityEditor; using UnityEngine;
public class ParticleSpawner : MonoBehaviour { public ParticleSystem prefab; public int systemCount = 128; public int particleEmissionRatePerSystem = 400; public float particleSystemShapeRadius = 1.0f; public float totalRadius = 5.0f; public float effectRange = 3.0f; public float effectStrength = 1.0f; public float oscillationSpeed = 10.0f; public bool hasTrails = true; public bool useJobSystem = false;
void Start() { var material = new Material(Shader.Find("Legacy Shaders/Particles/Additive")); material.SetTexture("_MainTex", AssetDatabase.GetBuiltinExtraResource<Texture2D>("Default-Particle.psd"));
for (int i = 0; i < systemCount; i++) { var go = GameObject.Instantiate(prefab); var ps = go.GetComponent<ParticleSystem>();
go.GetComponent<ParticleSystemRenderer>().sharedMaterial = material;
float x = (float)i / systemCount; float theta = x * Mathf.PI * 2;
var transform = go.GetComponent<Transform>(); transform.position = new Vector3(Mathf.Sin(theta), Mathf.Cos(theta), 0.0f) * totalRadius;
var main = ps.main; main.startColor = Color.HSVToRGB(x, Random.Range(0.5f, 1.0f), Random.Range(0.5f, 1.0f));
var emission = ps.emission; emission.rateOverTime = particleEmissionRatePerSystem;
var shape = ps.shape; shape.radius = particleSystemShapeRadius;
var trails = ps.trails; trails.enabled = hasTrails;
var updateJob = go.GetComponent<ParticleJob>(); updateJob.effectRange = effectRange; updateJob.effectStrength = effectStrength; updateJob.oscillationSpeed = oscillationSpeed; updateJob.useJobSystem = useJobSystem; } }
// UI void OnGUI() { float x = 25.0f; float y = 60.0f; float spacing = 40.0f;
EditorGUI.BeginChangeCheck();
GUIStyle backgroundStyle = new GUIStyle(GUI.skin.box); backgroundStyle.normal.background = Texture2D.whiteTexture; var oldColor = GUI.backgroundColor; GUI.backgroundColor = new Color(0.5f, 0.5f, 0.5f, 0.5f); GUI.Box(new Rect(x - 10, y - 35, 260, 230), "Options", backgroundStyle); GUI.backgroundColor = oldColor;
GUI.Label(new Rect(x, y, 140, 30), "Effect Range"); effectRange = GUI.HorizontalSlider(new Rect(x + 140, y + 5, 100, 30), effectRange, 0.0f, 10.0f); y += spacing;
GUI.Label(new Rect(x, y, 140, 30), "Effect Strength"); effectStrength = GUI.HorizontalSlider(new Rect(x + 140, y + 5, 100, 30), effectStrength, 0.0f, 10.0f); y += spacing;
GUI.Label(new Rect(x, y, 140, 30), "Oscillation Speed"); oscillationSpeed = GUI.HorizontalSlider(new Rect(x + 140, y + 5, 100, 30), oscillationSpeed, 0.0f, 20.0f); y += spacing;
hasTrails = GUI.Toggle(new Rect(x, y + 5, 140, 30), hasTrails, "Trails"); y += spacing;
useJobSystem = GUI.Toggle(new Rect(x, y + 5, 140, 30), useJobSystem, "Use C# Job System"); y += spacing;
if (EditorGUI.EndChangeCheck()) { ParticleJob[] updateJobs = GameObject.FindObjectsOfType<ParticleJob>(); for (int i = 0; i < updateJobs.Length; i++) { var updateJob = updateJobs[i]; updateJob.effectRange = effectRange; updateJob.effectStrength = effectStrength; updateJob.oscillationSpeed = oscillationSpeed; updateJob.useJobSystem = useJobSystem;
var ps = updateJob.GetComponent<ParticleSystem>();
var trails = ps.trails; trails.enabled = hasTrails; } } } }
Did you find this page useful? Please give it a rating:
Thanks for rating this page!
What kind of problem would you like to report?
Thanks for letting us know! This page has been marked for review based on your feedback.
If you have time, you can provide more information to help us fix the problem faster.
Provide more information
You've told us this page needs code samples. If you'd like to help us further, you could provide a code sample, or tell us about what kind of code sample you'd like to see:
You've told us there are code samples on this page which don't work. If you know how to fix it, or have something better we could use instead, please let us know:
You've told us there is information missing from this page. Please tell us more about what's missing:
You've told us there is incorrect information on this page. If you know what we should change to make it correct, please tell us:
You've told us this page has unclear or confusing information. Please tell us more about what you found unclear or confusing, or let us know how we could make it clearer:
You've told us there is a spelling or grammar error on this page. Please tell us what's wrong:
You've told us this page has a problem. Please tell us more about what's wrong:
Thank you for helping to make the Unity documentation better!
Your feedback has been submitted as a ticket for our documentation team to review.
We are not able to reply to every ticket submitted.