I've made a quick 2d animated planet proof of concept. Here is the live version:
http://estructor.altervista.org/animated_2d_planet_concept/
The current version does not seamlessly repeat either the cloud or the planet texture, so after a while the illusion is shattered <img src="{SMILIES_PATH}/icon_e_wink.gif" alt=";-)" title="Wink"> It should take relatively small effort to have those repeat.
The trick is very simple: mask out the cloud and planet textures with a circle using the blend effects. Please check the capx file how I achieved it. This effect is imperfect: it would be nice if we had access to a filter that would bulge the planet as a sphere. Perhaps someone here knows another trick to improve my simple version. It's pretty much one big fake.
I created all the effect maps in Photoline.
The planet resides on its own layer which I rotate and zoom out - but you could also use the pin behaviour to control the planet's position, for example.
You also need the Lite Tween behaviour installed for this example to work (although I could have applied the bullet behaviour as well).
behavior-litetween_t70700
Capx:
http://estructor.altervista.org/animated_2d_planet_concept/planet.capx
PS To create and render your own custom planet maps, check out the following links:
Planet creator that outputs all the maps you need:
http://www.blitzbasic.com/Community/pos ... opic=97336
Good solar system planet maps:
http://planetpixelemporium.com/planets.html
Interesting webgl experiment:
http://planetmaker.wthr.us/
http://wwwtyro.github.io/procedural.js/planet1/