How to draw circles with animated edges in iPhone / Open GL ES

Question

Could someone provide me with a start on the best way to go about this? What I want is circles within circles (for theoretical purpose let's say 3 circles). Each cirlces edge should be animated to mimic the aurora borealis (northern lights). They should flow and have subtle color changes. Any help would be greatly appreciated.

Some general questions:

• Use Open GL Project Template or View Based With drawing Graphics?
• How would you create the flowing animation?
• How would you blend the colors?

Thanks, -s

Answer 1

I read about using Particle Systems with OpenGL to get these kinds of effects. In a chapter in iPhone Advanced Projects the author gave an example that creates smoke and fire effects using particle systems (source code provided).

If you search for iphone particle systems you can find lots more.