ParticleSystem.GetParticles

Parameters

Returns

int The number of particles written to the input particle array (the number of particles currently alive).

Description

Gets the particles of this particle system.

This method is allocation free as long the input "particles" array is preallocated once (see example below). Note that only a small part of the particles array might be used as this depends on how many particles are currently alive in the particle system when calling GetParticles().

See Also: Particle, SetParticles.

using UnityEngine;

[RequireComponent(typeof(ParticleSystem))]
public class ParticleFlow : MonoBehaviour
{
    ParticleSystem m_System;
    ParticleSystem.Particle[] m_Particles;
    public float m_Drift = 0.01f;

    private void LateUpdate()
    {
        InitializeIfNeeded();

        // GetParticles is allocation free because we reuse the m_Particles buffer between updates
        int numParticlesAlive = m_System.GetParticles(m_Particles);

        // Change only the particles that are alive
        for (int i = 0; i < numParticlesAlive; i++)
        {
            m_Particles[i].velocity += Vector3.up * m_Drift;
        }

        // Apply the particle changes to the particle system
        m_System.SetParticles(m_Particles, numParticlesAlive);
    }

    void InitializeIfNeeded()
    {
        if (m_System == null)
            m_System = GetComponent<ParticleSystem>();

        if (m_Particles == null || m_Particles.Length < m_System.main.maxParticles)
            m_Particles = new ParticleSystem.Particle[m_System.main.maxParticles];
    }
}