Particles with custom shader

Hi guys! I have a problem with a formula in a custom shader. I would to copy this particles shader in this website:

I made a JSfiddle with my code:
As you can see in my example I am not able to do these movement:

  • In Y axis I am not able to restart particles from the floor
  • in X axis I’m not able to make some sort of random movement
  • I’m not able to make random alpha

Someone could help me?


An option from scratch. Use it as a starting point:


Ok Nice! thank you!