Hi guys, I am trying to imitate an aurora glow for 2d games.
I don't know if this is the right name, but it is used everywhere in Blizzard's Hearthstone card game
even on its homepage http://us.battle.net/hearthstone/en/, you can find 3 kind of aurora effect on its main banner
the banner is a movie file http://media.blizzard.com/hearthstone/videos/home-header-bg-video.webm, so its impossible to diagnose it
Here are some static screenshot
I've tried to do this with particle system, however, not satisfied with the result, and it is expensive too
any direction on how to generate this effect in real time?