i tried giving particles the Color (0,0,0,1), but they got invisible. making them dark also didn't work, they just got less visible. how can i get them black?
blending must be changed (it's adding color by default). Also you need to have a particle texture with alpha channel (unless you want square particles).
the current alphastate is
final AlphaState as1 = Core.getInstance().getDisplay().getRenderer().createAlphaState();
as1.setBlendEnabled(true);
as1.setSrcFunction(AlphaState.SB_SRC_ALPHA);
as1.setDstFunction(AlphaState.DB_ONE);
as1.setTestEnabled(true);
as1.setTestFunction(AlphaState.TF_GREATER);
as1.setEnabled(true);
why doesn't that one work? i mean if the color is 0,0,0 and alpha is 1, i should get a black result.
Try DB_ONE_MINUS_SRC_ALPHA
it worked. 
thx