[issue] batch particle sprite sheet

[AllenYu]

i create a looping particle system with sprite sheet and instantiate 50.
In the time of generation, it can not be batched.
After that, it batched well.

[karl_jones]

I’m not sure I understand. When is it batched and when is it not?
Do you have an example project?

[AllenYu]

There are some problems with my statement. And I made a demo.

In my opinion,the batches should always be 2.
But in the demo, It starts at 15, and finally stabilizes at 2.

3172528–241696–test.unitypackage (247 KB)

[karl_jones]

I have not had a chance to look yet but I suspect this is the issue:

Unity - Manual: Draw call batching

Semi-transparent Shaders usually require GameObjects to be rendered in back-to-front order for transparency to work. Unity first orders GameObjects in this order, and then tries to batch them, but because the order must be strictly satisfied, this often means less batching can be achieved than with opaque GameObjects.

[AllenYu]

There only two materials int this demo. AA(alpha additive) 3000(render Queue) AB(alpha blend) 3001(render Queue)
All the particles are looping. In the first looping, some particles can not be batched with the new born.

[AllenYu]

In the first looping, the different value of start delay will make the batch more difficult.

[AllenYu]

I find the problem! SpriteRenderer used Late Binding in unity2017, the atlas will not be correct when the particle system was born. Maybe it’s not the right time to use sprite sheet in particle system. I tried to use the grid sheet, the batch is always 2.