On the "Final Destination" stage. in "Super Smash Bros. Brawl" and "Super Smash Bros. Melee", the players fight on a platform that is seemingly moving through space.
I see particle effects, but I don't understand how they made the clouds, or the rest of it. I'm currently working on a breakout-clone in Unity3D, and would like to create a similar background for my game.
How can this effect be produced? How can a texture be made to fly towards the camera endlessly / seamlessly like that?