(Flash) 3D particles with depth of field and additive blending

This is an exercise to practise creating a 3D effect without using libraries.
The particles are blurred as they get close to the camera, and their trajectories are drawn with additive blending.
The code is not very clean yet, and there may be a way to get it to run much faster. I mean to try to rewrite the code later.

sample movie and scripts