How to create a Raining Effect(Particles) on Android?

Question

I am developing a 2d android strategy game, it runs on SurfaceView, so I can't(or can I?) use LibGdx's particle system. And I would like to make a raining effect, I am aiming for something like this( http://ridingwiththeriver.files.wordpress.com/2010/09/rain-fall-animation.gif ), I don't need the splash effect in the end (although that would be superb, but probably would take up a lot of system resources). How could I achieve that raining effect? Any ideas?

Answer 1

The easiest would be to put the rain drops in a PNG with alpha and display that at the end. You would only need a few frames to make it smooth, but it would eat up a bit of resources if this were a full screen image.

If you cannot afford this, you could put each distinct raindrop in a smaller PNG file with alpha, then display this (these) single PNG(s) multiple times. This would reduce the memory used a lot, although your rendering code will get a bit more complex, and depending on how many drops you have, it might affect performance.

A trade-off between the two would be to have a PNG file that contains more drops, but not for the full screen, and display that a few times.

You could have another frame (or frames) where the raindrop splashed, which you could display before ending the animation of each drop, or you could have the final frame in the large PNG contain the splashes.

Answer 2

There's one similar code from JakeWharton called DroidFlake. It seem like snowfall effect but worthy to check DroidFlake

Answer 3

There are many ways of doing this. You could create a sprite sheet like:

In that spritesheet, you could simply have a drop of water advance in each frame until it reaches the bottom and you create the splash effect. You then need to be able to animate it (very easy). You can then create multiple instances of the image, or draw the one image multiple times to create the rain storm.