I have a scene where I have a lot of instances of the same particle system. As the game will go for mobile, I fear the particles are calculated even when they are not shown. So to cut it short, I would like to know if the particle system is being calculated and rendered even if off-screen.
Yes they are calculated when offscreen as stated in this library's README (this was quite a problem for them). What is cool is that this library can be used to lower the performance lost by using a second camera. If you don't have much particles then it's not worth but it might be a great improvement if you run a game heavy on particle :
In our game, we're drawing several dozen screens worth of overlapping particles, so the speedup is pronounced.