Particle Systems

LibGDX has some amazing support for particle systems.  Particle systems provide a way to produce some great effects, like snow or flames.

I just added some basic support for particle systems to LibLOL.  These particles are not Actors.  They don't have meaning in the Physics world.  But they do provide some nice visual effects.

Using particle effects is pretty easy.  There's a new facility, Effect, which provides a factory method for making particle effects.  (Hopefully I'll add other effects some day, so I made the code a little bit generic.)  All you need to do is provide the name of a particle effect file, give it x and y coordinates, and then indicate a few other parameters (Z index, whether it should repeat).

The hard part is making the particle effect file.  There's a tutorial here.  In effect, there are three parts:

First, you need to set up Android Studio to run the particle effect editor.  This is a lot like the step you took to make a "Desktop" target for your game.  You'll use the "Run/Edit Configurations" menu option, and set the path to "com.badlogic.gdx.tools.particleeditor.ParticleEditor".  If you've done it correctly, you'll be able to choose ParticleEditor from the run options.  Running it should start a program that looks like this:

Second, you can play with all of the parameters in the program until you get the effect you want.  To do this correctly, your best bet is to set Pixels per meter to 20 (because LibLOL has a pixel-to-meter ratio of 20).  Once you've done that, you'll need to divide a lot of the values in the editor by 20 to get things back to a reasonable state.  Once you've got everything looking good with 20 pixels per meter, save the effect as a text file in your android/assets folder.

The third step is to load your effect, see what doesn't work nicely, and adjust accordingly.  I know it's unsatisfying to say "trial and error", but sometimes that's what it takes.