ADOFAIRenderer/Util/ParticleUtil.cs

using System;
using System.Runtime.CompilerServices;
using UnityEngine;

namespace ADOFAIRenderer.Util
{
    public static class ParticleUtil
    {
        private static readonly ConditionalWeakTable<ParticleSystem, ParticleSystemRenderer> Cache = new();

        public static ParticleSystemRenderer? GetRenderer(this ParticleSystem ps)
        {
            if (!ps) return null;
            if (Cache.TryGetValue(ps, out var renderer) && renderer) return renderer;

            var particleSystems = ps.GetComponents<ParticleSystem>();
            var renderers = ps.GetComponents<ParticleSystemRenderer>();
            var index = Array.IndexOf(particleSystems, ps);

            renderer = index >= 0 && index < renderers.Length ? renderers[index] : ps.GetComponent<ParticleSystemRenderer>();
            if (renderer) Cache.Add(ps, renderer);

            return renderer;
        }
    }
}