Hello, I am attempting to create an effect where certain line materials or sprite materials can glow. The problem is that most of the examples I have found are relying on intense colors to create a glow effect (similar to real life), where instead I want any color to be able to glow. For instance, in CSS, you can use a shadow to basically add a border glow to any object, even if that “glow” is black. Using an example like this, you could never make a color like black bloom as far as I have tried. And if you lowered the threshold enough so that even black could glow, then any color would also be able to glow making things non-selective.
Does anyone know of any method such that I can achieve a selective glow effect similar to how it’d be done with CSS? I know that’s an odd ask, but it’s the best example I can think of where you can make any color glow.
If you are crazy enough, you could try:
- fake bloom effect (it may have any color, lighter or darker than the rest of the scene). An example of fakeness: https://codepen.io/boytchev/full/ExdmvxE
- be negative – use the bloom on the inverted scene (so the dark object is bright and the bloom is bright), then again invert it (thus the bloom becomes dark).
That’s beautiful, but with thousands of objects I’m certain that’d turn my computer into an aluminum puddle 
I see, you are not crazy enough. A third approach is to start with a bloom shader and modify it. Maybe playing with blending modes could make dark bloom?
BTW, inverting the colors of a scene does not care about the number of objects drawn. The fake bloom, unfortunately, cares. A lot.
That might work, but it definitely feels like trying to wrangle the bloom shader to do something it isn’t originally meant to do. I guess I’m looking for a shader which applies to an object, doesn’t modify the object itself but instead mixes the surrounding pixels with a combination of its base color and the color of the background behind it. Perhaps this has a different name than bloom?