Particle systems are animated every time the scene is rendered.
Particle systems are animated every time the scene is rendered, using the time value last passed to the animate function, even if animate was not called between the render calls.
This is problematic when implementing stereo view or realtime reflections.
Easy fix would be to store a bool true in the scene when animate has been called, and set it false when the particle system manager animate has been called (it's supposedly called after position updates of instances *), so that it won't be called a second time without animate being called.
- For some reason, though, the particle systems lag one frame behind on the positioning information. If I put a mesh box instance in a particle system, and I spawn the particle system as well as a regular box shape instance, the box of the particle system will appear one frame later than the simple box shape. Similarly, if I move both of them the particle system's box will be moved one frame after the box shape.