My first Android release (under my own name) for a while is Color Storm, a Live Wallpaper for 2.* Android devices. It creates striking patterns and colors on the user’s Home screen.
It took about ten days to put together (as ever in Java under the Android SDK in Eclipse). It builds on pattern programs I have been working on for about 25 years when I used to tinker with plotting vector graphics on the Amstrad CPC. More recently I developed a Windows Media Player visualization around 2000.
That effect was heavily dependent on so-called back-buffer effects (modifying and redrawing the previous frame). This allows an animated vector line pattern to be converted into something that fills the screen with color.
However on this occasion I wanted to achieve a fuller effect using geometric effects. In Color Storm a fairly standard spiral pattern is combined with a particle processor to create a thick ribbon that changes thickness throughout its length. Shaded OpenGLES triangles are used and alpha values carefully tapered to give a smooth effect resembling a beam of light.
I put a lot of work into the interpolation engine. This smoothly transitions through a range of pattern values in order to achieve a wide range of visual effects without jarring changes in speed. I deliberately made the progress slow in order to create a restful rather than frantic pace that may be distracting for users concentrating on their home screen widgets.
I hope you enjoy the app! Search under Color Storm in the Market application, or use the barcode here (with Barcode Scanner or Google Goggles).