Sorry for the separate topic, og thread was too old to post in. This is mostly a question I wanted to ask of the creator 
R0J0hound, though anyone can chip in. The conditional opacity effect is available from this topic.
The effect would be really useful to me if not for an immediate snag I ran into - the effect will make any transparent (0% opacity) parts of a sprite highlight in black:
This also happens if the sprite's opacity is set to 0%, in which case it shows up as a black block. So basically, any pixels with 0% opacity show up opaque black. Is there some way to give it an exception so that anything invisible doesn't change opacity?
Edit: Might be the issue is more complicated than I thought. The effect doesn't just highlight invisible parts of the sprite in black, but a square area that is as long and tall as the edges of the object's bounding box:
To some extent I can mitigate this by using a black-to-alpha effect to hide the dark areas, but, the visual effect I was actually trying to achieve is to have the sprites at 0% opacity so that they're invisible unless they pass over an object in the background (similar to Source atop blend). Since conditional opacity makes them appear black at 0% op, black-to-alpha makes them completely invisible.
I guess the solution I'm trying to get to now is: is it possible to make conditional opacity still highlight an object at 0% opacity, but in the original colors of the sprite instead of black?