I'm using official Particle System extension from Daniel (https://github.com/Gamua/Starling-Extension-Particle-System) and have a question :
Is it possible to display particles over a png image with alpha and limit the particle only to the non alpha parts? E.g. I have a image of a banana and would like to display sparkling particles but only over the banana and not transparency corners of the image ?
I have tried all combinations of Context3DBlendFactors to be used for blendFactorSource and blendFactorDestination but none of them have provided this desired effect..
Also noticed that setting a display blend modes ( BlendMode.ADD, BlendMode.BELOW,BlendMode.ERASE,BlendMode.SCREEN,BlendMode.MULTIPLY.. etc) to a particle system or it's container have no effect whatsoever ?
This effect needs to be dynamic as the images will change, so I cannot use some sort of predefined mask shape to mask out the transparency areas, and computing mask out of png alpha area for every scene bitmap seems cpu expensive , this needs to work on mobiles as well..
Is there perhaps another way to achieve this?