some hardware module designers add “invisible” LEDs on their products, for example the makenoise 0-coast, which has no physical LEDs, visible on the panel, but their light is filtered by the panel, and create an luminescence effect.
my question is: does anyone know how to replicate this effect via software ?
many, thanks to all. I apologize for a possible repost, but trying to search I didn’t find a similar topic.
like this one ?
am doesn’t knew the module, and now i cant try it, but from what i see, probably it’s similar what i mean.
I’m not a dev, so I can’t help you, I just wanted to know if this was the kind of effect you were after. Also, the Instruo modules are NOT open source, so maybe contact the dev and ask how he did it ?
I hadn’t thought of contacting any developer who implements this effect,
thank you very much for the advice. 
A picture of the effect you want would be super helpful. There are several light elements on the 0-coast and several of them look like vcv rack LEDs to my eyes, but I’ve only seen videos of one.
A few things that might help you
VCV Rack does have a rectangular light you can use. I use it on my GlassPane module. That might help create the square light that 0-coast has.
VCV Rendering is broken up into several layers. I don’t know all of them but there is at least 3:
When drawing the lights, each light simply draws its shape in the right color to the screen. It also draws its own bloom effect, which is effectively a gradient that fades out to full transparency. I’d look at the source code for LightWidget to see more of how this works.
Hopefully the above is helpful. What follows is really nerdy dive into the technicality of lightning.
You said you wanted an “luminescence” effect. Luminescence usually refers to things that create their own light (without heat). Like glow in the dark paint. “Translucence” is the technical term for what’s happening on the 0-cost. Translucence mean letting light pass through diffusely. Imaging holding a flashlight inside a colorful shirt. This is actually what most LEDs are doing. A bare LED is a very bright point light. The case of most LEDs is a translucent plastic to “shape” the light into a larger, more disuse light. From what I can tell, the O-Coast is just doing the same thing again, with different shaped piece of plastic to get different shaped lights. So I think form VCV’s point of view, the 0-coast basically just has oddly shaped LEDs.
The typical ways to do this are a) with multiple SVG file that you switch out, or b) by doing all your own drawing. Switching SVG is pretty easy, but you need to use a frame buffer or it will be slow and use too much CPU.
My old EV3 VCO does something similar, if not identical. The waveform “pushbuttons” switch from a grey to a larger blue when activated. The ugly code is here: SquinkyVCV-main/WaveformSwitch.h at master · kockie69/SquinkyVCV-main · GitHub