How use atlas for particlesystems in unity5.5

Unity Engine
1 
void Start()
    {

        ps = GetComponent<ParticleSystem>();
        psr = GetComponent<ParticleSystemRenderer>();

        // emit in a sphere with no speed
        var main = ps.main;
        main.startSpeedMultiplier = 0.0f;
        main.simulationSpace = ParticleSystemSimulationSpace.World;    // so our particle positions don't require any extra transformation, to compare with the mouse position
        var emission = ps.emission;
        emission.rateOverTimeMultiplier = 200.0f;
        var shape = ps.shape;
        shape.shapeType = ParticleSystemShapeType.Sphere;
        shape.radius = 4.0f;
        psr.sortMode = ParticleSystemSortMode.YoungestInFront;

        // send custom data to the shader
        psr.EnableVertexStreams(ParticleSystemVertexStreams.Custom1);
        for (int i = 0; i < ps.main.maxParticles; i++)
        {
            customData.Add(new Vector4(0.5f, 0.5f, 0, 0));//offset the uv at the atlas
        }
        ps.SetCustomParticleData(customData, ParticleSystemCustomData.Custom1);
    }

I want to chang the uv in start ,but can not work .I do not want to chang the uv in UPDATE,it is not good performance

2876149--210924--atlas_fx.jpg
2876149--210924--atlas_fx.jpg1434×730 240 KB

2

Custom data is likely cleared each update, or at least cleared for each new particle on spawn. Setting the array thus will do nothing as when each particle gets spawned the custom data is removed.

You’re better off (ab)using the texture sheet animation module which you can just set once at start.

3

I think the textureSheet is not work,because the atlas contains different size rectangle.Why not open uv data in start for developper??this is good performance and easy to archeive.