When multiple different particle emitters are in close proximity to each other the game engine will always render the particles generated from the emitter closer to the camera over the ones generated by the other emitter regardless of the actual 3D position of the particles.
EDIT: I should also add that this bug predates the release of particle flipbooks
The generated particles should be rendered on top of each other based on their actual position relative to the camera regardless of which emitter they originated from.
Particles of different particle emitters are rendered on top of each other purely based on the position of the emitter as seen here:
An example for this can be found here:
Issue Area: Engine Issue Type: Display Impact: High Frequency: Constantly
Nothing to do with the transparency level, the issue occurs even with fully opaque images.
Z-Fighting is something else and unrelated to this as the engine has a clear priority which particles it should render on top.
The problem is that it prioritizes the position of the emitter over the position of the actual particles when deciding which particles should be rendered on top which is why you can see them flicker in the video as I change the position of my camera and as it changes which emitter is closer to it.
I might be totally wrong but this behavior has been around for quite a while and looks like it functions as it would’ve normally.
Is there a post where it is intended that the behavior work as the actual behavior you described? I don’t remember seeing a post describing the behavior you said though that probably just means I don’t look around too much